JP2022070477A - Fault detection device for detecting fault of power conversion apparatus and motor driving device - Google Patents

Abstract

To provide a fault detection device which promptly and accurately detects a fault location and a fault content of a power conversion apparatus, and a motor driving device comprising the same.SOLUTION: A fault detection device 1 for detecting a fault of a power conversion apparatus 2 for performing a power conversion from DC to AC or a power conversion from AC to DC by turning-on and turning-off operations of a plurality of switching elements constituting a bridge circuit, comprises: a command generation unit 11 for generating a plurality of command patterns consisting of combinations of ON commands and OFF commands for the respective switching elements; a current acquisition unit 12 for acquiring a detection value of a current flowing in the bridge circuit; and a fault determination unit 13 for determining the fault of the power conversion apparatus 2 on the basis of the combination of the ON command and the OFF command for each switching element and the detection value of the current which is acquired by the current acquisition unit 12 when the command pattern is commanded for each switching element in a state where a DC voltage is applied to a DC side of the power conversion apparatus 2 and a load circuit 3 is connected to an AC side of the power conversion apparatus 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a failure detection device and a motor drive device for detecting a failure of a power conversion device.

Inverters with PWM control and converters with PWM control and 120-degree energization are converted from direct current to alternating current or from alternating current to direct current by turning on and off switching elements provided on each of the upper and lower arms of the bridge circuit. It is a power conversion device that performs power conversion. For example, in a motor drive device that controls the drive of a motor installed in a machine tool or a robot, AC power input from an AC power supply is converted into DC power by a PWM control method or a 120-degree energization type converter and DC. It is output to the link, and the DC voltage in the DC link is converted into AC power by a PWM control type inverter, and this AC power is output as the drive power of the motor. The DC link refers to the circuit part that electrically connects the DC output side of the converter and the DC input side of the inverter, and is the "DC link section", "DC link", "DC link section", or "DC intermediate". It is also called "circuit".

The failures that can occur in the power conversion device correspond to, for example, an open failure related to the switching element, a short failure related to the switching element, a failure related to the current detection unit provided in the power conversion device, and a switching element. There is a failure related to the provided overcurrent detector.

Of these, an open failure is a failure in which the switching element does not close and remains open even though the switching control unit issues an on command (close command) to the switching element. Further, a short-circuit failure is a failure in which the switching element does not open and remains closed even though the switching control unit issues an off command (open command) to the switching element. These open failures and short-circuit failures are caused by the fact that the switching element itself does not function normally, and the case where the drive circuit that applies the gate voltage for turning the switching element on and off does not function normally. This may be due to the fact that the switching control unit that controls the drive circuit does not function normally. Hereinafter, open failures that occur in the switching element due to any one of the switching element itself, the drive circuit, and the switching control unit are collectively referred to as "open failure related to the switching element". Similarly, short-circuit failures that occur in the switching element due to any one of the switching element itself, the drive circuit, and the switching control unit are collectively referred to as "short-circuit failure related to the switching element".

Various methods are known as methods for detecting a failure that occurs in a power conversion device.

For example, an inverter device that converts a DC voltage into an AC voltage and outputs it to an AC machine, and has an upper arm switch element and a lower arm switch element connected in series, and an inverter circuit connected to the AC machine. A current detecting means for detecting a current flowing through the inverter circuit and a diagnostic device for diagnosing an abnormality in the inverter circuit and an abnormality in the AC machine or the connection are provided, and the diagnostic device includes the upper arm switch element and the upper arm switch element. The ON / OFF of the lower arm switch element is controlled to output a single pulse voltage to the AC machine, and a short-circuit failure of the AC machine or the connection is diagnosed from the current value obtained by the current detecting means. The inverter device has a capacitor in which a voltage for driving the upper arm switch element is charged by turning on the lower arm switch element, and the upper arm switch is charged by the voltage charged in the capacitor. The diagnostic device further includes a bootstrap circuit for driving the element and a capacitor voltage detecting means for detecting the voltage charged in the capacitor of the bootstrap circuit, and the diagnostic device turns on the upper arm switch element and the lower arm switch element. An inverter device is known that controls / OFF and uses the voltage value obtained by the capacitor voltage detecting means to diagnose an abnormality in the inverter circuit and an abnormality in the AC machine or the connection (the AC device or the connection). For example, see Patent Document 1).

For example, the semiconductor module (40) is configured together with the high-side switching element (700H, 701H) and the low-side switching element (700L, 701L) as the switching element (70) constituting the upper and lower arms of a plurality of phases, and the switching element is described. A voltage detection unit (82) for detecting the voltage between the main electrodes of the switching element constituting each arm or the phase voltage of each phase upper and lower arm, and the voltage detection unit. A determination unit (84) that determines whether or not a short-circuit failure has occurred in the switching element based on the voltage value detected by the determination unit, and a determination unit that determines that a failure has occurred, the failure has occurred. A control device including a drive unit (85) that turns off the switching element and turns on the switching element on the same side as the phase different from the failed switching element is known (for example, Patent Document). See 2.).

For example, an inverter circuit (20) for supplying power to a motor, a drive circuit (30) for driving the inverter circuit, a control element (40) for controlling the drive circuit, and a current flowing through the inverter circuit are used. The inverter circuit includes a current detection unit (70) that detects and outputs the detection result to the control element, the inverter circuit is connected to a predetermined load (90) in the inspection mode, and the control element is in the inspection mode. In the above, among the current value appropriateness determination and the current protection failure detection of the inverter circuit operated by the inspection signal by outputting the inspection signal corresponding to the predetermined load to the drive circuit and operating the inverter circuit. There is known an inverter board that performs at least one of the above using the detection result of the current detection unit, determines the presence or absence of a failure in the inverter circuit, and outputs the failure detection determination result to the outside (for example, Patent Document). See 3.).

For example, a power semiconductor having an emitter electrode and an emitter sense terminal that outputs a sense current corresponding to the current flowing through the emitter electrode, and performing a switching operation for converting DC power supplied from a DC power supply into AC power. An element, an overcurrent detection circuit that detects an overcurrent flowing through the power semiconductor element based on the sense current, and an overcurrent simulation circuit that outputs a simulated signal simulating the overcurrent to the overcurrent detection circuit. A power conversion device comprising the above is known (see, for example, Patent Document 4).

Japanese Unexamined Patent Publication No. 2020-08645 Japanese Unexamined Patent Publication No. 2019-075959 Japanese Unexamined Patent Publication No. 2018-061328 International Publication No. 2016/021329

In the power conversion device provided in the motor drive device, a failure may occur in various places such as a switching element, a current detection unit, and an overcurrent detection unit. In particular, since a plurality of switching elements are provided in the power conversion device, the failure points are various, and the types of failures are divided into open failures and short failures. Therefore, it takes time and effort to identify the failure location and the failure content of the power conversion device. For example, at the time of shipping test of a motor drive device, the motor is actually driven by the motor drive device to detect the motor rotation speed and the motor current, and if there is an abnormality in each of these values, it is uniformly determined to be a defective product. .. Therefore, it is not possible to specify the failure location and the failure content of the power conversion device provided in the motor drive device. Therefore, it is desired to develop a technique capable of quickly and accurately detecting the failure location and the failure content of the power conversion device provided in the motor drive device.

According to one aspect of the present disclosure, a failure detection device that detects a failure of a power conversion device that converts DC to AC power or AC to DC power by turning on and off a plurality of switching elements constituting a bridge circuit. Is a command generation unit that generates a plurality of command patterns consisting of a combination of on-command and off-command for each switching element, and each of the plurality of command patterns has a command generation unit having different combinations of on-command and off-command. A combination of an on command and an off command for each switching element in the command pattern, a current acquisition unit that acquires the detected value of the current flowing through the bridge circuit, and a DC voltage applied to the DC side of the power conversion device and the AC side of the power conversion device. A failure of the power conversion device is caused based on the current detection value acquired by the current acquisition unit when each switching element is operated by commanding a command pattern to each switching element while the load circuit is connected to. It is provided with a failure determination unit for determination.

Further, according to one aspect of the present disclosure, the motor drive device performs power conversion from direct current to alternating current or power conversion from alternating current to direct current by on / off operation of a plurality of switching elements constituting the bridge circuit. A power conversion device that generates power used for driving the power converter and the above-mentioned failure detection device that detects a failure of the power conversion device are provided.

According to one aspect of the present disclosure, it is possible to quickly and accurately detect the failure location and the failure content of the power conversion device provided in the motor drive device.

It is a figure which shows the failure detection apparatus which detects the failure of the three-phase power conversion apparatus by one Embodiment of this disclosure, and the motor drive apparatus provided with the failure detection apparatus. It is a figure which shows the 1st failure determination command pattern used for detecting the open failure and the short-circuit failure which are related to the switching element in the three-phase power conversion apparatus by one Embodiment of this disclosure. It is a flowchart which shows the detection process of the open failure or the short-circuit failure which concerns on the switching element in the failure detection apparatus which detects the failure of the three-phase power conversion apparatus by one Embodiment of this disclosure, and the motor drive apparatus provided with the failure detection apparatus. It is a figure which illustrates the closed circuit formed when the 1st failure determination command pattern is commanded to the switching element in the three-phase power conversion apparatus by one Embodiment of this disclosure. Relationship between a switching element in which an open failure has occurred in a failure detection device for detecting a failure in a three-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device and a first failure determination command pattern. It is a figure which shows. Relationship between a switching element in which a short-circuit failure has occurred in a failure detection device for detecting a failure in a three-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device, and a first failure determination command pattern. It is a figure which shows. It is a figure which shows the failure detection apparatus which detects the failure of the single-phase power conversion apparatus by one Embodiment of this disclosure, and the motor drive apparatus provided with the failure detection apparatus. It is a figure which shows the 1st failure determination command pattern used for detecting the open failure and the short-circuit failure which are related to the switching element in the single-phase power conversion apparatus by one Embodiment of this disclosure. It is a flowchart which shows the detection process of the open failure or the short-circuit failure which concerns on the switching element in the failure detection apparatus which detects the failure of the single-phase power conversion apparatus by one Embodiment of this disclosure, and the motor drive apparatus provided with the failure detection apparatus. Relationship between a switching element in which an open failure has occurred in a failure detection device for detecting a failure in a single-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device and a first failure determination command pattern. It is a figure which shows. Relationship between a switching element in which a short-circuit failure has occurred in a failure detection device for detecting a failure in a single-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device, and a first failure determination command pattern. It is a figure which shows. It is a figure which shows the relationship between the current flowing through the switching element in the bridge circuit of a power conversion apparatus, and the on-time of the switching element. Disclosed is a failure detection process for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure, an open failure and a short-circuit failure related to a switching element in a motor drive device including the failure detection device, and a failure detection process of a current detection unit. It is a flowchart. The figure which shows the 2nd failure determination command pattern used for detecting the failure of the overcurrent detection part provided corresponding to each of the switching elements in the three-phase power conversion apparatus by one Embodiment of this disclosure. Is. The failure detection process of the overcurrent detection unit provided corresponding to each of the failure detection device for detecting the failure of the three-phase power conversion device and the switching element in the motor drive device including the failure detection device according to the embodiment of the present disclosure. It is a flowchart which shows. It is a figure which illustrates the closed circuit formed when the 2nd failure determination command pattern is commanded to the switching element in the three-phase power conversion apparatus by one Embodiment of this disclosure. It is a figure which shows the relationship between the overcurrent detection part and the 2nd failure determination command pattern in the failure detection device which detects the failure of the three-phase power conversion device by one Embodiment of this disclosure, and the motor drive device provided with the failure detection device. .. In the failure detection device for detecting the failure of the three-phase power conversion device according to one embodiment of the present disclosure, an open failure and a short-circuit failure related to a switching element in a motor drive device including the failure detection device, a failure of a current detection unit, and a switching element. It is a flowchart (the 1) which shows the failure detection process of the overcurrent detection part provided correspondingly. In the failure detection device for detecting the failure of the three-phase power conversion device according to one embodiment of the present disclosure, an open failure and a short-circuit failure related to a switching element in a motor drive device including the failure detection device, a failure of a current detection unit, and a switching element. It is a flowchart (the 2) which shows the failure detection process of the overcurrent detection part provided correspondingly. In the failure detection device for detecting the failure of the three-phase power conversion device according to one embodiment of the present disclosure, an open failure and a short-circuit failure related to a switching element in a motor drive device including the failure detection device, a failure of a current detection unit, and a switching element. It is a flowchart (3) which shows the failure detection process of the overcurrent detection part provided correspondingly.

Hereinafter, a failure detection device and a motor drive device for detecting a failure of the power conversion device will be described with reference to the drawings. These drawings have been scaled accordingly for ease of understanding. The embodiment shown in the drawings is an example for carrying out, and is not limited to the illustrated embodiment.

First, a failure detection device for detecting a failure of a power conversion device including a three-phase bridge circuit and a motor drive device including the failure detection device will be described.

FIG. 1 is a diagram showing a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device.

The motor drive device 100 according to the embodiment of the present disclosure is a motor (power conversion from direct current to alternating current or power conversion from alternating current to direct current by on / off operation of six switching elements constituting a three-phase bridge circuit. A power conversion device 2 that generates power used for driving (not shown) and a failure detection device 1 that detects a failure of the power conversion device 2 are provided.

The three-phase power conversion device 2 includes a three-phase bridge circuit, a switching control unit 21, a drive circuit 22, a current detection unit 23, and a voltage detection unit 24. A positive electrode terminal 25 and a negative electrode terminal 26 are provided on the DC side of the power conversion device 2.

Examples of the power conversion device 2 include, for example, a PWM control type inverter, a PWM control type converter (rectifier), and a 120-degree energization type converter (rectifier). When the power conversion device 2 is an inverter, an AC load circuit such as an AC motor is connected to the AC side of the power conversion device 2, and a converter is connected to the DC side via a capacitor or a DC power supply is connected. Will be done. When the power conversion device 2 is a converter, an AC power supply is connected to the AC side of the power conversion device 2, and an inverter is connected to the DC side via a capacitor, or a DC load circuit such as a DC motor is connected. Or a DC power supply is connected. Although the details will be described later, when the failure detection device 1 detects the failure of the power conversion device 2, the load circuit 3 for failure detection is connected to the AC side of the power conversion device 2 and the power conversion device 2 is connected. A DC power supply for fault detection is connected to the DC side of the unit, and a DC voltage is applied.

The three-phase bridge circuit in the power converter 2 has three legs corresponding to each of the three phases. Each leg has an upper arm and a lower arm. Each upper arm and each lower arm are provided with a power element including a switching element and a diode connected in antiparallel to the switching element. Here, the switching elements provided on each upper arm are referred to as S ₁ , S ₂ and S ₃ , and the switching elements provided on each lower arm are referred to as S ₄ , S ₅ and S ₆ . Examples of switching elements include IGBTs, FETs, thyristors, GTOs, transistors and the like. The IGBT has a gate, an emitter and a collector as its terminals. The FET has a gate, a drain and a source as its terminals. Thyristors and GTOs have gates, anodes and cathodes as their terminals. The transistor has a base, an emitter and a collector as its terminals. When a transistor is used as the switching element, "base" is read as "gate" and the embodiment according to the present disclosure is applied.

The switching control unit 21 generates an on command and an off command for each switching element based on a drive command received from a higher-level control unit (not shown) or a command pattern received from a command generation unit 11 described later. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command.

The configuration of the switching control unit 21 and the drive circuit 22 described here is merely an example. For example, the switching control unit 21 may be defined by including some of a position command generation unit, a position control unit, a speed control unit, a current control unit, a torque command creation unit, and the like. Further, for example, the switching control unit 21 and the drive circuit 22 may be integrated and configured. Further, for example, a power element composed of a switching element and a diode may be configured by an IPM (intelligent power module), and in this case, the IPM has functions such as a drive circuit 22 function and an overcurrent detection function. Further, as the drive circuit 22, a driver IC having an overcurrent detection function called a DESAT detection circuit may be used. The DESAT detection circuit is provided for each switching element. For example, in an IGBT driven by a DESAT detection circuit, when an overcurrent flows through an turned on switching element, the voltage between the collector and the emitter rises more than when it is normally turned on by the DESAT detection circuit. By detecting, the overcurrent can be detected.

Probes (two probes T ₁ and T ₂ in the example shown in FIG. 1) are provided on at least two phases of the three-phase power lines on the AC side of the bridge circuit of the power conversion device 2, and the current detection unit 23 is used. , The current on the AC side of the bridge circuit of the power conversion device 2 is detected via the probes T ₁ and T ₂ . Further, at least one of the positive and negative power lines on the DC side of the bridge circuit of the power conversion device 2 is provided with a probe (probe T ₃ on the positive power line in the example shown in FIG. 1), and the current detection unit 23 is provided with a probe. , The DC side current (particularly overcurrent) of the bridge circuit of the power conversion device 2 is detected via the probe T ₃ . When the power element consisting of a switching element and a diode is configured by IPM instead of the current detection process on the DC side of the bridge circuit of the power conversion device 2 by the current detection unit 23, the overcurrent detection function of IPM may be used. Alternatively, if the drive circuit 22 is composed of a driver IC having a DESAT detection circuit, the overcurrent detection function of the DESAT detection circuit may be used.

Further, the voltage detection unit 24 detects the voltage on the DC side of the bridge circuit of the power conversion device 2. The current detection value detected by the current detection unit 23 and the voltage detection value detected by the voltage detection unit 24 are the power conversion control in the power conversion device 2 and the motor drive control in the motor drive device 100 having the power conversion device 2. It is also used in the failure detection process of the failure detection device 1.

The failure detection device 1 according to the embodiment of the present disclosure includes a command generation unit 11, a current acquisition unit 12, and a failure determination unit 13. Further, the failure detection device 1 includes a voltage acquisition unit 14 and a current estimation unit 15 according to the details of the failure to be detected by the failure detection device 1. The failure detection device 1 may be built in the motor drive device 100, or may be detachably connected to the power conversion device 2. Further, the failure detection device 1 can be connected to the existing power conversion device 2.

The command generation unit 11 generates six command patterns including a combination of an on command and an off command for each switching element in a three-phase bridge circuit. Each of the six command patterns has different combinations of on and off commands. Although the details will be described later, the command generation unit 11 generates a first failure determination command pattern in order to detect an open failure and a short failure related to the switching element, and corresponds to each of the switching elements. A second failure determination command pattern is generated in order to detect a failure of the provided overcurrent detection unit (not shown). That is, the command pattern generated by the command generation unit 11 is used for detecting a failure, and is a normal power conversion control of the power conversion device 2 or a motor commanded by a higher-level control unit (not shown). It is different from the command pattern used for the normal motor drive control of the drive device 100. The command pattern generated by the command generation unit 11 is sent to the failure determination unit 13 and the switching control unit 21. The switching control unit 21 generates an on command and an off command for each switching element based on the command pattern generated by the command generation unit 11.

When the failure detection device 1 detects a failure of the power conversion device 2, a load circuit 3 for failure detection is connected to the AC side of the power conversion device 2, and a positive voltage is connected to the DC side of the power conversion device 2. A DC power supply (not shown) for failure detection is connected via the terminal 25 and the negative electrode terminal 26, and a DC voltage is applied. The DC power source for failure detection may be a battery or a converter (rectifier) connected to an AC power source.

The load circuit 3 is an inductive load or a resistant load, such as an AC motor, a reactor, and a resistor. The connection of the load circuit 3 to the AC side of the power conversion device 2 and the disconnection of the connection may be performed via a switch unit (not shown) that opens and closes the electric circuit. At the time of shipment or maintenance of the power conversion device 2 or the motor drive device 100, the switch unit is closed to connect the load circuit 3 to the AC side of the power conversion device 2, and the power conversion device 2 or the motor drive device 100 is normally operated. Occasionally, the switch unit may be opened to disconnect the AC side of the power conversion device 2 from the load circuit 3.

The current acquisition unit 12 acquires the current detection value by the current detection unit 23.

In the failure determination unit 13, the content of the combination of the on command and the off command for each switching element in the command pattern, the DC voltage is applied to the DC side of the power conversion device 2, and the load circuit 3 is on the AC side of the power conversion device 2. A failure of the power conversion device 2 is determined based on the current detection value acquired by the current acquisition unit 12 when a command pattern is commanded to each switching element in the connected state to operate each switching element. do. That is, in the example shown in FIG. 1, in order to detect a failure of the three-phase power conversion device 2, each switching element is operated by commanding each of six different command patterns. The current acquisition unit 12 acquires six types of current detection values corresponding to each of the six command patterns. If an open failure or short-circuit failure has occurred in the switching element, or if the overcurrent detection unit provided corresponding to the switching element has failed, there is some change in the current detection value acquired by the current acquisition unit 12. appear. Therefore, in one embodiment of the present disclosure, the failure determination unit 13 is based on the correspondence between the combination of the on command and the off command for each switching element in the command pattern and the detected value of the current acquired by the current acquisition unit 12. The location where the failure of the phase power conversion device 2 occurs and the content of the failure are determined.

The determination result by the failure determination unit 13 is output to the outside as the detection result of the failure detection device 1. The detection result of the failure detection device 1 is displayed, for example, on a display unit (not shown). Examples of the display unit include a single display device, a display device attached to the upper control unit, a display device attached to the power conversion device 2, a display device attached to the motor drive device 100, and a personal computer and a mobile terminal. There is a display device and so on. Alternatively, instead of the display unit, the detection result report detected by the failure detection device 1 may be output by an audio device that emits a sound such as a voice, a speaker, a buzzer, or a chime. As a result, the operator can quickly and accurately grasp the temperature of the power conversion device 2. Therefore, it becomes easy for the operator to take measures such as urgently stopping the power conversion device 2 or the motor drive device 100, or replacing or repairing the parts related to the failed portion in the power conversion device 2.

The voltage acquisition unit 14 acquires the detected value of the voltage on the DC side of the power conversion device detected by the voltage detection unit 24. The detected value of the acquired voltage is sent to the current estimation unit 15.

The current estimation unit 15 determines the estimated value of the current flowing through each switching element based on the voltage detection value acquired by the voltage acquisition unit 14, the time when the switching element is commanded to be ON, and the impedance of the load circuit 3. calculate. The calculated estimated value of the current is sent to the failure determination unit 13.

FIG. 2 is a diagram showing a first failure determination command pattern used for detecting an open failure and a short failure related to a switching element in a three-phase power conversion device according to an embodiment of the present disclosure.

As a first failure determination command pattern for detecting an open failure and a short failure of the three-phase power conversion device 2 shown in FIG. 1, six different command patterns are generated by the command generation unit 11. Each of the six first failure determination command patterns is identified by using the identification number N (where N is a natural number of 1 to 6). Each of the six first failure determination command patterns PN switches between the switching element of any one upper arm constituting the bridge circuit and the lower arm in any one leg different from the leg to which the upper arm belongs. It consists of a combination of an on-command for an element and an off-command for a switching element other than the on-commanded switching element. More details are as follows.

The first failure determination command pattern P1 is an on-command for the switching element S ₁ of the upper arm and the switching element S ₅ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₂ , S ₃ , S ₄ and S ₆ other than the elements S ₁ and S ₅ .

The first failure determination command pattern P2 is an on-command for the switching element S ₁ of the upper arm and the switching element S ₆ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₂ , S ₃ , S ₄ and S ₅ other than the elements S ₁ and S ₆ .

The first failure determination command pattern P3 is an on-command for the switching element S ₂ of the upper arm and the switching element S ₆ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₁ , S ₃ , S ₄ and S ₅ other than the elements S ₂ and S ₆ .

The first failure determination command pattern P4 is an on-command to the switching element S ₂ of the upper arm and the switching element S ₄ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₁ , S ₃ , S ₅ and S ₆ other than the elements S ₂ and S ₄ .

The first failure determination command pattern P5 is an on-command to the switching element S ₃ of the upper arm and the switching element S ₄ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₁ , S ₂ , S ₅ and S ₆ other than the elements S ₃ and S ₄ .

The first failure determination command pattern P6 is an on-command for the switching element S ₃ of the upper arm and the switching element S ₅ of the lower arm in a leg different from the leg to which the upper arm belongs, and the on-commanded switching. It consists of a combination of an off command for switching elements S ₁ , S ₂ , S ₄ and S ₆ other than the elements S ₃ and S ₅ .

FIG. 3 is a flowchart showing a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure and an open failure or short failure detection process related to a switching element in a motor drive device including the failure detection device. be.

In the detection process of open failure or short failure related to the switching element in the failure detection device 1 and the motor drive device 100 including the failure detection device 1, a DC voltage is applied to the DC side of the three-phase power conversion device 2 and the power conversion device 2 has a DC voltage. It is executed with the load circuit 3 connected to the AC side.

First, in step S101, the command generation unit 11 sets the identification number N of the first failure determination command pattern to 1 as an initial setting. The setting of the identification number N of the first failure determination command pattern in step S101 may be performed, for example, by an input operation using an input device to the failure detection device 1 of the operator, or the failure detection device. It may be automatically performed at the start of the failure detection process according to 1, or may be automatically performed when the power of the failure detection device 1 is turned on.

In step S102, the command generation unit 11 commands the switching control unit 21 for the first failure determination command pattern PN. The switching control unit 21 generates an on command and an off command for each switching element based on the first failure determination command pattern PN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. Since a DC voltage is applied to the DC side of the three-phase power conversion device 2 and a load circuit 3 is connected to the AC side of the power conversion device 2, two of the six switching elements are switched on. If the element is normally on-operating, the DC-side positive terminal 25 of the power conversion device 2, the load circuit 3, and the DC-side negative-negative terminal of the power conversion device 2 are passed through the two on-operation switching commands. A closed circuit is formed at 26. The first failure determination command pattern PN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S103, the current acquisition unit 12 acquires the current detection value by the current detection unit 23 corresponding to the first failure determination command pattern PN. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13. The failure determination unit 13 stores the detected value of the current sent from the current acquisition unit 12 in association with the first failure determination command pattern PN used when acquiring the detected value of the current. do.

In step S104, the command generation unit 11 determines whether or not the identification number N of the first failure determination command pattern PN is 6. If it is determined that the identification number N of the first failure determination command pattern PN is 6, the process proceeds to step S106, and it is not determined that the identification number N of the first failure determination command pattern PN is 6. In that case, the process proceeds to step S105.

In step S105, the command generation unit 11 increments the identification number N of the first failure determination command pattern PN by one. After that, the process returns to step S102.

In step S106, the failure determination unit 13 determines the correspondence between the combination of the on command and the off command for each switching element in the six first failure determination command patterns PN and the detected value of the current acquired by the current acquisition unit 12. Based on this, the location where the open failure or short failure of the three-phase power conversion device 2 occurs is determined. After that, a series of failure detection processes are terminated.

The first failure determination command pattern PN described above is used to detect an open failure and a short failure related to the switching element in the three-phase power conversion device 2. Subsequently, a case where an open failure related to the switching element in the three-phase power conversion device 2 is detected by using the first failure determination command pattern will be described.

The failure determination unit 13 is based on the correspondence between the combination of the on command and the off command for each switching element in the six first failure determination command patterns PN and the detected values of the six currents acquired by the current acquisition unit 12. The location where the open failure of the three-phase power conversion device 2 occurs is determined. More specifically, the failure determination unit 13 detects the six currents acquired by the current acquisition unit 12 when each switching element is operated based on each of the six first failure determination command patterns PN. Of these, when the detected value of the current acquired by the current acquisition unit 12 under at least two first failure determination command patterns PN is less than the first threshold value, the at least two first failure determination commands are used. It is determined that an open failure related to the switching element ordered to be turned on in two of the pattern PNs has occurred.

FIG. 4 is a diagram illustrating a closed circuit formed when a first failure determination command pattern is commanded to a switching element in a three-phase power conversion device according to an embodiment of the present disclosure. In a state where a DC voltage is applied to the DC side of the three-phase power conversion device 2 and the load circuit 3 is connected to the AC side of the power conversion device 2, as an example, in FIG. 4A, for each switching element. Illustrates a closed circuit that can be formed when the first failure determination command pattern P1 is commanded. In FIG. 4B, the first failure determination command pattern P2 is commanded to each switching element. Illustrates a closed circuit that can be formed when In FIG. 4, the failure detection device 1 is not shown.

As shown in FIG. 4A, in the first failure determination command pattern P1, for the switching element S1 of the upper arm and the switching element _S5 of the lower arm in a _leg different from the leg to which the upper arm belongs. Is commanded to be turned on, and is commanded to be turned off for switching elements S ₂ , S ₃ , S ₄ , and S ₆ other than the switching elements S ₁ and S ₅ ordered to be turned on. Therefore, if all six switching elements are functioning normally, a closed circuit including a positive electrode terminal 25, a switching element S ₁ , a load circuit 3, a switching element S ₅ , and a negative electrode terminal 26 is formed.

As shown in FIG. 4B, in the first failure determination command pattern P2, for the switching element S1 of the upper arm and the switching element _S6 of the lower arm in a _leg different from the leg to which the upper arm belongs. Is commanded to be turned on, and is commanded to be turned off for switching elements S ₂ , S ₃ , S ₄ , and S ₅ other than the switching elements S ₁ and S ₆ ordered to be turned on. Therefore, if all six switching elements are functioning normally, a closed circuit including a positive electrode terminal 25, a switching element S ₁ , a load circuit 3, a switching element S ₆ , and a negative electrode terminal 26 is formed.

As described above, in both the first failure determination command pattern P1 and the _first failure determination command pattern P2, the switching element S1 is instructed to be ON. Therefore, if the switching element S ₁ is functioning normally, a current flows through the closed circuit via the switching element S ₁ in both FIGS. 4 (A) and 4 (B), and the current acquisition unit 12 causes the current acquisition unit 12. The detected value of the acquired current is a normal value larger than zero. However, if the switching element S ₁ has an open failure, it is assumed that the switching element S ₁ is on-commanded under the first failure determination command pattern P1 and the first failure determination command pattern P2. However, since the switching element S ₁ is not closed but remains open, no current flows in the closed circuit, and the detected value of the current acquired by the current acquisition unit 12 is close to zero. The same can be said for the other first failure determination command pattern and the switching element. Therefore, in one embodiment of the present disclosure, this phenomenon is used to detect the occurrence of an open failure.

The failure determination unit 13 has two first failure determination command patterns P1 among the six current detection values acquired by the current acquisition unit 12 corresponding to each of the six first failure determination command patterns PN. And when the detected value of the current acquired by the current acquisition unit 12 under P2 becomes a value close to zero, the switching element ordered to be turned on in the two first failure determination command patterns P1 and P2. It is determined that an open failure related to S ₁ has occurred. A first threshold value close to zero and larger than zero (for example, several tens of milliamperes) is set in advance and stored in the failure determination unit 13. Whether or not the detected value of the current acquired by the current acquisition unit 12 is close to zero may be determined based on the comparison result between the detected value of the current acquired by the current acquisition unit 12 and the first threshold value. .. That is, the failure determination unit 13 determines that the current detection value acquired by the current acquisition unit 12 is close to zero when the current detection value acquired by the current acquisition unit 12 is less than the first threshold value. do.

Of the six current detection values acquired by the current acquisition unit 12 corresponding to each of the six first failure determination command patterns PN, current acquisition is performed under three or more first failure determination command patterns. Even when the detected value of the current acquired by the unit 12 is less than the first threshold value, the switching element that has been on-commanded in "two" of the three or more first failure determination command patterns is similarly used. It can be determined that a related open failure has occurred.

FIG. 5 shows a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure, a switching element in which an open failure has occurred in a motor drive device including the failure detection device, and a first failure determination command. It is a figure which shows the relationship with a pattern. In FIG. 5, with respect to the first failure determination command patterns P1 to P6, the case where the detected value of the current acquired by the current acquisition unit 12 is less than the first threshold value (that is, a value close to zero) is indicated by “x”. , The case where the value is equal to or higher than the first threshold value (that is, a normal value sufficiently larger than zero) is indicated by “◯”. Further, in FIG. ₅ , the case where it is determined that an open failure has occurred for _each of the switching elements S1 to S6 is indicated by “x”. The failure determination unit ₁₃ detects an open failure of the switching elements S1 to S6 in the _three -phase power conversion device 2 based on the correspondence shown in FIG.

For example, when all the detected values of the current acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6 are equal to or higher than the first threshold value, the failure determination unit 13 is used for all switching elements S. ₁ to S ₆ are judged not to have an open failure.

For example, among the current detection values acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6, the current acquisition unit 12 under the two first failure determination command patterns P5 and P6. When the detected value of the current acquired by is less than the first threshold value, the failure determination unit ₁₃ relates to the switching element S3 that has been on-commanded in the two first failure determination command patterns P5 and P6. It is determined that an open failure has occurred.

For example, among the current detection values acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6, the current acquisition unit 12 under the three first failure determination command patterns P4 to P6. When the detected value of the current acquired by is less than the first threshold value, the failure determination unit 13 has two first failure determination commands among the three first failure determination command patterns P4 to P6. It is related to the open failure related to the switching element S ₄ which is on-commanded under the patterns P4 and P5, and the switching element S ₃ which is on-commanded under the two first failure determination command patterns P5 and P6. It is determined that an open failure has occurred.

For example, among the current detection values acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6, the current acquisition unit 12 under the four first failure determination command patterns P3 to P6. When the detected value of the current acquired by is less than the first threshold value, the failure determination unit 13 has two first failure determination commands among the four first failure determination command patterns P3 to P6. It is related to the open failure related to the switching element S ₂ ordered under the patterns P3 and P4 and the switching element S ₄ related to the switching element S 4 ordered to be turned on under the two first failure determination command patterns P4 and P5. It is determined that an open failure to be performed and an open failure related to the switching element S3 to be turned _on under the two first failure determination command patterns P5 and P6 have occurred.

For example, when all the detected values of the current acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6 are less than the first threshold value, "upper arm switching elements S ₁ and S ₂ ". And S ₃ open faults only, and in addition to the upper arm switching elements S ₁ , S ₂ and S ₃ open faults, at least one of the lower arm switching elements S ₄ , S ₅ and S ₆ . "Open failure related to lower arm switching elements S ₄ , S ₅ and S ₆ " occurred, and "Open failure related to lower arm switching elements S ₄ , S ₅ and S ₆ " occurred. In addition, one of the "open failures related to at least one of the switching elements S ₁ , S ₂ and S ₃ of the upper arm" has occurred. Therefore, when all the detected values of the current acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P6 are less than the first threshold value, the failure determination unit 13 is at least "upper arm". It is determined that "an open failure related to the switching elements S ₁ , S ₂ and S ₃ of the lower arm" or "an open failure related to the switching elements S ₄ , S ₅ and S ₆ of the lower arm" has occurred.

Subsequently, a case where a short-circuit failure related to the switching element in the three-phase power conversion device 2 is detected by using the first failure determination command pattern will be described.

As shown in FIG. 4A, in the first failure determination command pattern P1, for the switching element S1 of the upper arm and the switching element _S5 of the lower arm in a _leg different from the leg to which the upper arm belongs. Is commanded to be turned on, and is commanded to be turned off for switching elements S ₂ , S ₃ , S ₄ , and S ₆ other than the switching elements S ₁ and S ₅ ordered to be turned on. Therefore, if all six switching elements are functioning normally, a closed circuit including a positive electrode terminal 25, a switching element S ₁ , a load circuit 3, a switching element S ₅ , and a negative electrode terminal 26 is formed.

As shown in FIG. 4B, in the first failure determination command pattern P2, for the switching element S1 of the upper arm and the switching element _S6 of the lower arm in a _leg different from the leg to which the upper arm belongs. Is commanded to be turned on, and is commanded to be turned off for switching elements S ₂ , S ₃ , S ₄ , and S ₅ other than the switching elements S ₁ and S ₆ ordered to be turned on. Therefore, if all six switching elements are functioning normally (that is, if an open failure has not occurred), the positive electrode terminal 25, the switching element S ₁ , the load circuit 3, the switching element S ₆ , and the negative electrode A closed circuit consisting of terminals 26 is formed.

As described above, in both the first failure determination command pattern P1 and the _first failure determination command pattern P2, the switching element S1 is instructed to be ON. Therefore, if the switching element S ₁ is functioning normally, in both FIGS. 4 (A) and 4 (B), a normal current flows through the switching element S ₁ in the closed circuit, and the current detection unit 23 detects this normal current via probe _T3 . That is, the detected value of the current acquired by the current acquisition unit 12 from the current detection unit 23 becomes a normal value. However, if the switching element S ₄ has a short-circuit failure, the switching element S ₄ remains closed even though the off command remains. When an ON command is given to the switching element S ₁ under the first failure determination command pattern P1 and the first failure determination command pattern P2, the switching element S ₁ closes, so that the bridge circuit of the power conversion device 2 A short circuit including a switching element S ₁ and a switching element S ₄ belonging to the same leg as the positive terminal 25 and a negative terminal 26 is configured when viewed from the DC side of the above. As a result, when a DC voltage is applied to the DC side of the bridge circuit of the power conversion device 2, an overcurrent flows in the short circuit including the positive electrode terminal 25, the switching element S ₁ , the switching element S ₄ , and the negative electrode terminal 26. The same can be said for the other first failure determination command pattern and the switching element. Therefore, in one embodiment of the present disclosure, the occurrence of a short-circuit failure is detected based on the occurrence of this overcurrent.

The current detection unit 23 detects this overcurrent via the probe T ₃ . The overcurrent detection value acquired from the current detection unit 23 is acquired by the current acquisition unit 12. The failure determination unit 13 has two first failure determination command patterns P1 among the six current detection values acquired by the current acquisition unit 12 corresponding to each of the six first failure determination command patterns PN. When the detected values of the two currents acquired by the current acquisition unit 12 under P2 and P2 both indicate an overcurrent, the switching element S that is on-commanded in the two first failure determination command patterns P1 and P2. It is determined that a short-circuit failure related to the switching element S ₄ that has been instructed to be off has occurred in the leg to which ₁ belongs. A second threshold value (for example, about 1.2 times the rated value) larger than the normal value (for example, the rated value) is set in advance and stored in the failure determination unit 13. Whether or not the detected value of the current acquired by the current acquisition unit 12 indicates an overcurrent may be determined based on the comparison result between the detected value of the current acquired by the current acquisition unit 12 and the second threshold value. That is, the failure determination unit 13 determines that the current detection value acquired by the current acquisition unit 12 indicates an overcurrent when the current detection value acquired by the current acquisition unit 12 is larger than the second threshold value. do.

The overcurrent flowing in the short circuit including the positive electrode terminal 25, the switching element S ₁ , the switching element S ₄ , and the negative electrode terminal 26 is detected by the current detection unit 23 via the probe T ₃ . When a power element consisting of a switching element and a diode is configured by IPM instead of the current detection process on the DC side of the bridge circuit of the power converter 2 by the current detection unit 23 (current detection process via the probe T ₃ ). May detect the overcurrent using the overcurrent detection function of the IPM, or if the drive circuit 22 is composed of a driver IC having a DESAT detection circuit, the overcurrent detection function of the DESAT detection circuit is used. The overcurrent may be detected.

Of the six current detection values acquired by the current acquisition unit 12 corresponding to each of the six first failure determination command patterns PN, current acquisition is performed under three or more first failure determination command patterns. Even when the detected value of the current acquired by the unit 12 is larger than the second threshold value, it can be determined that a short-circuit failure related to the switching element has occurred in the same manner.

FIG. 6 shows a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure, a switching element in which a short-circuit failure has occurred in a motor drive device including the failure detection device, and a first failure determination command. It is a figure which shows the relationship with a pattern. In FIG. 6, regarding the first failure determination command patterns P1 to P6, the case where the detected value of the current acquired by the current acquisition unit 12 is larger than the second threshold value (that is, the case of indicating an overcurrent) is “x”. , And the case where the value is equal to or less than the second threshold value (that is, the normal value) is indicated by “◯”. Further, in FIG. ₆ , for _each of the switching elements S1 to S6, the case where it is determined that a short-circuit failure has occurred is indicated by “x”, and it is determined that a short-circuit failure may have occurred. The case is indicated by "△". The failure determination unit 13 detects a short _- circuit failure of the switching elements S1 to S6 in the _three -phase power conversion device 2 based on the correspondence shown in FIG.

For example, of the two second current detection values on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6. When the detection values of the two currents acquired by the current acquisition unit under the failure determination command patterns P4 and P5 of 1 are larger than the second threshold value, the failure determination unit 13 causes the two first failure determination commands. It is determined that a short failure related to the switching element S ₁ that has been commanded off has occurred in the leg to which the switching element S ₄ that has been commanded to be turned on in patterns P4 and P5 belongs.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the third third. When the detection values of the three currents acquired by the current acquisition unit under the failure determination command patterns P3 to P5 of 1 are larger than the second threshold value, the failure determination unit 13 causes the three first failure determination commands. A short-circuit failure related to the switching element S ₅ to which the switching element S 2 to which the switching element S ₂ has been ordered to be turned on in the first failure determination command patterns P3 and P5 of the patterns P3 to P5 belongs has been ordered to be off. , Off-commanded in the leg to which the switching element S4, which was on-commanded in the two first failure-determining command patterns P4 and ₅ of the three first failure-determining command patterns P3 to P5, belongs. It is determined that a short-circuit failure related to the switching element S ₁ has occurred.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P1 to P3 and P6 of 1 are larger than the second threshold value, the failure determination unit 13 determines the four first failures. Related to the switching element S ₂ that was commanded off in the leg to which the switching element S ₅ that was commanded on in the first failure determination command patterns P1 and P6 of the command patterns P1 to P3 and P6 belongs. The short failure to be performed and the leg to which the switching element S 6 to which the switching element S ₆ has been on-commanded in the two first failure determination command patterns P2 and P3 of the four first failure determination command patterns P1 to P3 and P6 belong. It is determined that a short-circuit failure related to the switching element S3 _, which has been instructed to be off, has occurred.

As described above, the combination P1 and P6 of the first failure determination command pattern used for detecting the short failure of the switching element S ₂ and the first failure determination command used for detecting the short failure of the switching element S ₃ are used. With the combination of patterns P2 and P3, all of the four first failure determination command patterns P1 to P3 and P6 are "used up" in the short failure determination process. However, in addition to the combination "P1 and P6" and "P2 and P3" of the two first failure determination command patterns used when it is determined that the short failure has occurred, the switching element S ₁ is turned on. There is also a combination of two first failure determination command patterns P1 and P2 to be commanded. Since all of the four first failure determination command patterns P1 to P3 and P6 are used up in the short failure determination process, the _first failure determination command patterns P1 and P2 are described as "switching element S1. It just happens to appear as "on command", and there is a possibility that the short failure related to the switching element S ₄ that was actually commanded off in the leg to which the switching element S ₁ belongs has not actually occurred. There is. On the other hand, there is a possibility that a short-circuit failure related to the switching element S ₄ that has been instructed to be off in the leg to which the switching element S ₁ belongs actually occurs. Therefore, the failure determination unit 13 is different from the combination “P1 and P6” and “P2 and P3” of the two first failure determination command patterns used when it is determined that the short failure has occurred. Regarding the switching element S ₄ which was on-commanded in the two first failure determination command patterns P1 and P2 having a combination and was instructed to be off in the leg to which the switching element S ₁ belongs, "a short-circuit failure has occurred. "Is not confirmed, and the judgment is limited to the estimation such as" there is a possibility that a short failure has occurred ".

Similar to the above, as a combination of the first failure judgment command pattern that makes a judgment only "there is a possibility that a short failure has occurred" without confirming that "a short failure has occurred". , "P1 and P4 to P6", "P2 to P5", "P1 to P4", "P1, P2, P5 and P6", and "P3 to P6".

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P1 and P4 to P6 of 1 are larger than the second threshold value, the failure determination unit 13 determines the four first failures. Related to the switching element S ₁ that was commanded off in the leg to which the switching element S ₄ that was commanded on in the first failure determination command patterns P4 and P5 of the command patterns P1 and P4 to P6 belongs. The short failure to be performed and the leg to which the switching element S ₅ to which the switching element S5 has been on-commanded in the two first failure determination command patterns P1 and P6 of the four first failure determination command patterns P1 and P4 to P6 belong. It is determined that a short-circuit failure related to the switching element S ₂ that has been instructed to be turned off has occurred. The failure determination unit 13 uses a combination different from the combinations “P4 and P5” and “P1 and P6” of the two first failure determination command patterns used when determining that the short failure has occurred. There is a possibility that a short failure has occurred with respect to the switching element S ₆ which has been commanded on in the two first failure determination command patterns P5 and P6 and has been commanded off in the leg to which the switching element S ₃ belongs. judge.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P2 to P5 of 1 are larger than the second threshold value, the failure determination unit 13 causes the four first failure determination commands. A short-circuit failure related to the switching element S ₃ to which the switching element S 6 to which the switching element S ₆ has been ordered to be turned on in the first failure determination command patterns P2 and P3 of the patterns P2 to P5 belongs has been ordered to be off. , The off command is given in the leg to which the switching element S ₄ commanded on in the two first failure judgment command patterns P4 and P5 of the four first failure judgment command patterns P2 to P5 belongs. It is determined that a short-circuit failure related to the switching element S ₁ has occurred. The failure determination unit 13 uses a combination different from the combinations “P2 and P3” and “P4 and P5” of the two first failure determination command patterns used when determining that the short failure has occurred. There is a possibility that a short failure has occurred with respect to the switching element S ₅ which has been commanded on in the two first failure determination command patterns P3 and P4 and has been commanded off in the leg to which the switching element S ₂ belongs. judge.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P1 to P4 of 1 are larger than the second threshold value, the failure determination unit 13 causes the four first failure determination commands. A short failure related to the switching element S ₄ to which the switching element S 1 to which the switching element S ₁ has been ordered to be turned on in the first failure determination command patterns P1 and P2 of the patterns P1 to P4 belongs has been ordered to be off. , The off command is given in the leg to which the switching element S ₂ that has been on-commanded in the two first failure-determining command patterns P3 and P4 of the four first failure-determining command patterns P1 to P4 belongs. It is determined that a short-circuit failure related to the switching element S ₅ has occurred. The failure determination unit 13 uses a combination different from the combinations “P1 and P2” and “P3 and P4” of the two first failure determination command patterns used when determining that the short failure has occurred. There is a possibility that a short failure has occurred with respect to the switching element S ₃ which has been commanded on in the two first failure determination command patterns P2 and P3 and has been commanded off in the leg to which the switching element S ₆ belongs. judge.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P1, P2, P5 and P6 of 1 are larger than the second threshold value, the failure determination unit 13 is the first of the four. The switching element that was commanded off in the leg to which the switching element S1 that was commanded on in the _first failure judgment command pattern P1 and P2 of the fault determination command patterns P1, P2, P5 and P6 belongs. A short failure related to S4 and switching on-commanded in two first failure determination command patterns P5 and P6 of the _four first failure determination command patterns P1, P2, P5 and P6. It is determined that a short-circuit failure related to the switching element S ₆ that has been instructed to be off has occurred in the leg to which the element S ₃ belongs. The failure determination unit 13 uses a combination different from the combinations “P1 and P2” and “P5 and P6” of the two first failure determination command patterns used when determining that the short failure has occurred. There is a possibility that a short failure has occurred with respect to the switching element S ₂ which has been commanded on in the two first failure determination command patterns P1 and P6 and has been commanded off in the leg to which the switching element S ₅ belongs. judge.

For example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 to P6, the fourth ones. When the detection values of the four currents acquired by the current acquisition unit under the failure determination command patterns P3 to P6 of 1 are larger than the second threshold value, the failure determination unit 13 causes the four first failure determination commands. A short-circuit failure related to the switching element S ₅ to which the switching element S 2 to which the switching element S ₂ has been ordered to be turned on in the first failure determination command patterns P3 and P4 of the patterns P3 to P6 belongs has been ordered to be off. , Off-commanded in the leg to which the switching element S3 _, which was on-commanded in the two first failure-determining command patterns P5 and P6 of the four first failure-determining command patterns P3 to P6, belongs. It is determined that a short-circuit failure related to the switching element S ₆ has occurred. The failure determination unit 13 uses a combination different from the combinations “P3 and P4” and “P5 and P6” of the two first failure determination command patterns used when determining that the short failure has occurred. There is a possibility that a short failure has occurred with respect to the switching element S ₁ that has been commanded on in the two first failure determination command patterns P4 and P5 and has been commanded off in the leg to which the switching element S ₄ belongs. judge.

For example, all the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the six first failure determination command patterns P1 to P6 are the first. When it is larger than the threshold value of 2, the combination of the two first failure determination command patterns for on-commanding one switching element is "P4 and P5, P1 and P6, P2 and P3" and "P1 and P2, P3". And P4, P5 and P6 ”. Of these, regarding the combination of the first failure determination command patterns "P4 and P5, P1 and P6, P2 and P3", the short failure related to the switching element is the two first failure determination command patterns. The switching element S1 that was commanded off in the leg to which the switching element S4 that was commanded _on in P4 and P5 belongs, and the switching element S that was commanded to be turned on in the two _first failure determination command patterns P1 and P6. Switching element S 2 that was commanded off in the leg to which ₅ belongs, and switching that was commanded off in the leg to which the switching element S ₆ that was commanded on in the _two first failure determination command patterns P2 and P3 belong. It is generated in the element _S3 . Regarding the combination of the first failure determination command patterns "P1 and P2, P3 and P4, P5 and P6", the short failure related to the switching element is the two first failure determination command patterns P1 and P2. The switching element S4 that was ordered to be off in the _leg to which the switching element S1 that was commanded to be turned on belongs to the switching element S4 that was commanded to be turned off in the _{two first} failure determination command patterns P3 and P4. The switching element S ₅ that was commanded off in the leg, and the switching element S ₆ that was commanded off in the leg to which the switching element S ₃ that was commanded on in the two first failure determination command patterns P5 and P6 belong. It is occurring in. Therefore, in the failure determination unit 13, a short failure related to the switching element is caused by all of the switching elements S ₁ , S ₂ and S ₃ in the upper arm of the bridge circuit, or the switching elements S ₄ and S ₅ in the lower arm of the bridge circuit. And it is determined that all of S ₆ have occurred.

As described above, according to the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 including the failure detection device 1, the switching element in the three-phase power conversion device 2 is used by using the first failure determination command pattern. It is possible to quickly and accurately detect the location of an open failure or short failure related to the above.

Subsequently, a failure detection device for detecting a failure of a power conversion device including a single-phase bridge circuit and a motor drive device including the failure detection device will be described.

FIG. 7 is a diagram showing a failure detection device for detecting a failure of a single-phase power conversion device according to an embodiment of the present disclosure and a motor drive device including the failure detection device.

The motor drive device 100 according to the embodiment of the present disclosure is a motor (power conversion from direct current to alternating current or power conversion from alternating current to direct current by on / off operation of four switching elements constituting a single-phase bridge circuit. A power conversion device 2 that generates electric power used for driving (not shown) and a failure detection device 1 that detects a failure of the power conversion device 2 are provided.

The single-phase power conversion device 2 includes a single-phase bridge circuit, a switching control unit 21, a drive circuit 22, a current detection unit 23, and a voltage detection unit 24. A positive electrode terminal 25 and a negative electrode terminal 26 are provided on the DC side of the power conversion device 2.

Examples of the single-phase power conversion device 2 include, for example, a PWM control type inverter, a PWM control type converter (rectifier), and a 120-degree energization type converter (rectifier). Examples of various circuits connected to the AC side and the DC side of the single-phase power conversion device 2 are the same as those given in the description of the three-phase power conversion device.

The single-phase bridge circuit in the power converter 2 has two legs corresponding to each phase of the single phase. Each leg has an upper arm and a lower arm. Each upper arm and each lower arm are provided with a power element including a switching element and a diode connected in antiparallel to the switching element. Here, the switching elements provided on each upper arm are referred to as S ₁ and S ₂ , and the switching elements provided on each lower arm are referred to as S ₃ and S ₄ . Examples of switching elements are the same as those given in the description of the three-phase power conversion device.

A probe (probe T ₁ in the example shown in FIG. 7) is provided for at least one phase of the power lines on the AC side of the single-phase bridge circuit of the power conversion device 2, and the current detection unit 23 uses the probe T ₁ as a probe. The current on the AC side of the power conversion device 2 (bridge circuit) is detected via the current. Further, at least one of the positive and negative power lines on the DC side of the bridge circuit of the power conversion device 2 is provided with a probe (probe T ₃ on the positive power line in the example shown in FIG. 1), and the current detection unit 23 is provided with a probe. , The DC side current (particularly overcurrent) of the bridge circuit of the power conversion device 2 is detected via the probe T ₃ . When the power element consisting of a switching element and a diode is configured by IPM instead of the current detection process on the DC side of the bridge circuit of the power conversion device 2 by the current detection unit 23, the overcurrent detection function of IPM may be used. Alternatively, if the drive circuit 22 is composed of a driver IC having a DESAT detection circuit, the overcurrent detection function of the DESAT detection circuit may be used.

The switching control unit 21, drive circuit 22, voltage detection unit 24, positive electrode terminal 25, and negative electrode terminal 26 in the single-phase power conversion device 2 are the same as those described for the three-phase power conversion device 2. The current detection value detected by the current detection unit 23 and the voltage detection value detected by the voltage detection unit 24 are the power conversion control in the power conversion device 2 and the motor drive control in the motor drive device 100 having the power conversion device 2. It is also used in the failure detection process of the failure detection device 1.

The failure detection device 1 according to the embodiment of the present disclosure includes a command generation unit 11, a current acquisition unit 12, and a failure determination unit 13. Further, the failure detection device 1 includes a voltage acquisition unit 14 and a current estimation unit 15 according to the failure content to be detected by the failure detection device 1. The failure detection device 1 may be built in the motor drive device 100, or may be detachably connected to the power conversion device 2. The failure detection device 1 can also be connected to the existing power conversion device 2.

Since the command generation unit 11 generates a command pattern for the switching element of the single-phase bridge circuit, four command patterns different from each other are generated. The command generation unit 11 generates a first failure determination command pattern in order to detect an open failure and a short failure related to the switching element, and an overcurrent detection unit provided corresponding to each of the switching elements. A second failure determination command pattern is generated in order to detect a failure (not shown). That is, the command pattern generated by the command generation unit 11 is used for detecting a failure, and is a normal power conversion control of the power conversion device 2 or a motor commanded by a higher-level control unit (not shown). It is different from the command pattern used for the normal motor drive control of the drive device 100. The command pattern generated by the command generation unit 11 is sent to the failure determination unit 13 and the switching control unit 21. The switching control unit 21 generates an on command and an off command for each switching element based on the command pattern generated by the command generation unit 11.

When the failure detection device 1 detects a failure of the power conversion device 2, a load circuit 3 for failure detection is connected to the AC side of the power conversion device 2, and a positive voltage is connected to the DC side of the power conversion device 2. A DC power supply (not shown) for failure detection is connected via the terminal 25 and the negative electrode terminal 26, and a DC voltage is applied. The example of the load circuit 3 is the same as that given in the description of the three-phase power conversion device.

The current acquisition unit 12 is the same as that mentioned in the description of the three-phase power conversion device 2.

In the failure determination unit 13, the content of the combination of the on command and the off command for each switching element in the command pattern, the DC voltage is applied to the DC side of the power conversion device 2, and the load circuit 3 is on the AC side of the power conversion device 2. A failure of the power conversion device 2 is determined based on the current detection value acquired by the current acquisition unit 12 when a command pattern is commanded to each switching element in the connected state to operate each switching element. do. That is, in the example shown in FIG. 7, in order to detect the failure of the single-phase power conversion device 2, each of the four different command patterns is commanded to operate each switching element. The current acquisition unit 12 acquires four types of current detection values corresponding to each of the four command patterns. If an open failure or short-circuit failure has occurred in the switching element, or if the overcurrent detection unit provided corresponding to the switching element has failed, there is some change in the current detection value acquired by the current acquisition unit 12. appear. Therefore, in one embodiment of the present disclosure, the failure determination unit 13 simply bases on the correspondence between the combination of the on command and the off command for each switching element in the command pattern and the detected value of the current acquired by the current acquisition unit 12. The location where the failure of the phase power conversion device 2 occurs and the content of the failure are determined. The determination result by the failure determination unit 13 is output to the outside as the detection result of the failure detection device 1. The detection result of the failure detection device 1 is displayed, for example, on a display unit (not shown). The example of the display unit is the same as that given in the description of the three-phase power conversion device.

FIG. 8 is a diagram showing a first failure determination command pattern used for detecting an open failure and a short failure related to a switching element in a single-phase power conversion device according to an embodiment of the present disclosure.

As a first failure determination command pattern for detecting an open failure and a short failure of the single-phase power conversion device 2 shown in FIG. 7, four different command patterns are generated by the command generation unit 11. Each of the four first failure determination command patterns is identified by using the identification number N (where N is a natural number of 1 to 4). Each of the four first failure determination command patterns PN is an on-command for any one upper arm switching element and any one lower arm switching element constituting the bridge circuit, and the on-command. It consists of a combination of an off command for switching elements other than the switching element. More details are as follows.

The first failure determination command pattern P1 includes an on-command for the switching element S ₁ of the upper arm and the switching element S ₄ of the lower arm, and a switching element S ₂ other than the on-commanded switching elements S ₁ and S ₄ . It consists of a combination of and an off command for _S3 .

The first failure determination command pattern P2 includes an on-command for the switching element S ₂ of the upper arm and the switching element S ₃ of the lower arm, and a switching element S ₁ other than the on-commanded switching elements S ₂ and S ₃ . It consists of a combination of and an off command for _S4 .

The first failure determination command pattern P3 includes an on-command for the switching element S ₁ of the upper arm and the switching element S ₃ of the lower arm, and a switching element S ₂ other than the on-commanded switching elements S ₁ and S ₃ . It consists of a combination of and an off command for _S4 .

The first failure determination command pattern P4 includes an on-command for the switching element S ₂ of the upper arm and the switching element S ₄ of the lower arm, and a switching element S ₁ other than the on-commanded switching elements S ₂ and S ₄ . It consists of a combination of and an off command for _S3 .

FIG. 9 is a flowchart showing a failure detection device for detecting a failure of a single-phase power conversion device according to an embodiment of the present disclosure and an open failure or short failure detection process related to a switching element in a motor drive device including the failure detection device. be.

In the detection process of open failure or short failure related to the switching element in the failure detection device 1 and the motor drive device 100 including the failure detection device 1, a DC voltage is applied to the DC side of the single-phase power conversion device 2 and the power conversion device 2 has a DC voltage. It is executed with the load circuit 3 connected to the AC side.

First, in step S201, the command generation unit 11 sets the identification number N of the first failure determination command pattern to 1 as an initial setting. The setting of the identification number N of the first failure determination command pattern in step S201 may be performed, for example, by an input operation using an input device to the failure detection device 1 of the operator, or the failure detection device. It may be automatically performed at the start of the failure detection process according to 1, or may be automatically performed when the power of the failure detection device 1 is turned on.

In step S202, the command generation unit 11 commands the switching control unit 21 for the first failure determination command pattern PN. The switching control unit 21 generates an on command and an off command for each switching element based on the first failure determination command pattern PN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. The first failure determination command pattern PN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S203, the current acquisition unit 12 acquires the current detection value by the current detection unit 23 corresponding to the first failure determination command pattern PN. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13. The failure determination unit 13 stores the detected value of the current sent from the current acquisition unit 12 in association with the first failure determination command pattern PN used when acquiring the detected value of the current. do.

In step S204, the command generation unit 11 determines whether or not the identification number N of the first failure determination command pattern PN is 4. If it is determined that the identification number N of the first failure determination command pattern PN is 4, the process proceeds to step S206, and it is not determined that the identification number N of the first failure determination command pattern PN is 4. In that case, the process proceeds to step S205.

In step S205, the command generation unit 11 increments the identification number N of the first failure determination command pattern PN by one. After that, the process returns to step S202.

In step S206, the failure determination unit 13 corresponds to the combination of the on command and the off command for each switching element in the four first failure determination command patterns PN and the detected value of the current acquired by the current acquisition unit 12. Based on this, the location where the open failure or short failure of the single-phase power conversion device 2 occurs is determined. After that, a series of failure detection processes are terminated.

The first failure determination command pattern described above is used to detect an open failure and a short failure related to the switching element in the single-phase power conversion device 2. Subsequently, a case where an open failure related to the switching element in the single-phase power conversion device 2 is detected by using the first failure determination command pattern will be described.

When the failure detection device 1 detects an open failure related to the switching element in the single-phase power conversion device 2, the failure determination unit 13 is turned on for each switching element in the four first failure determination command patterns PN. Based on the correspondence between the combination of the command and the off command and the detected values of the four currents acquired by the current acquisition unit 12, the location where the open failure of the single-phase power conversion device 2 occurs is determined.

FIG. 10 shows a failure detection device for detecting a failure of a single-phase power conversion device according to an embodiment of the present disclosure, a switching element in which an open failure has occurred in a motor drive device including the failure detection device, and a first failure determination command. It is a figure which shows the relationship with a pattern. In FIG. 10, with respect to the first failure determination command patterns P1 to P4, the case where the detected value of the current acquired by the current acquisition unit 12 is less than the first threshold value (that is, a value close to zero) is indicated by “x”. , The case where the value is equal to or higher than the first threshold value (that is, a normal value sufficiently larger than zero) is indicated by “◯”. Further, in FIG. ₁₀ , the case where it is determined that an open failure has occurred for _each of the switching elements S1 to S4 is indicated by “x”. The failure determination unit ₁₃ detects an open failure of the switching elements S1 to S4 in the _single -phase power conversion device 2 based on the correspondence shown in FIG.

The failure determination unit 13 has two or three of the four current detection values acquired by the current acquisition unit 12 when each switching element is operated based on each of the four first failure determination command patterns. If the detected values of the two or three currents acquired by the current acquisition unit 12 under the first failure determination command pattern are less than the first threshold value, the two or three first failure determinations are made. It is determined that an open failure related to the switching element that was on-commanded in two of the command patterns has occurred. In the case of the single-phase power conversion device 2, as in the case of the three-phase power conversion device, a first threshold value (for example, several tens of milliamperes) that is close to zero and larger than zero is set in advance in the failure determination unit 13. Remember. Whether or not the detected value of the current acquired by the current acquisition unit 12 is close to zero may be determined based on the comparison result between the detected value of the current acquired by the current acquisition unit 12 and the first threshold value. .. That is, the failure determination unit 13 determines that the current detection value acquired by the current acquisition unit 12 is close to zero when the current detection value acquired by the current acquisition unit 12 is less than the first threshold value. do.

For example, among the detected values of the current acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P4, the current acquisition unit 12 under the two first failure determination command patterns P1 and P3. When the detected value of the current acquired by is less than the first threshold value, the failure determination unit 13 relates to the switching element S1 that has been on-commanded in the two _first failure determination command patterns P1 and P3. It is determined that an open failure has occurred.

For example, among the current detection values acquired by the current acquisition unit 12 under the first failure determination command patterns P1 to P4, the current acquisition unit 12 under the three first failure determination command patterns P2 to P4. When the detected value of the current acquired by is less than the first threshold value, the failure determination unit 13 has two first failure determination commands among the three first failure determination command patterns P2 to P4. It is related to the open failure related to the switching element S3 which was on _- commanded under the patterns P2 and P3, and the switching element S2 which was on-commanded under the _two first failure determination command patterns P2 and P4. It is determined that an open failure has occurred.

When the failure determination unit 13 operates each switching element based on each of the four first failure determination command patterns, the detection values of the four currents acquired by the current acquisition unit 12 are less than the first threshold value. In some cases, the combination of the two first failure determination command patterns that command one switching element on is of "P1 and P3", "P2 and P4", "P2 and P3", and "P1 and P4". There are four types. If at least two of these four types are adopted as the first failure determination command pattern for on-commanding one switching element, all four first failure determination command patterns P1 to P6 are open. It can be used up in the failure judgment process. Here, the _first failure determination command patterns P1 and P3 turn on the switching element S1. The first failure determination command patterns P2 and P4 turn on the switching element S ₂ . The first failure determination command patterns P2 and P3 turn _on the switching element S3. The first failure determination command patterns P1 and P4 turn on the switching element S ₄ . Therefore, in the failure determination unit 13, the detection values of the four currents acquired by the current acquisition unit 12 when each switching element is operated based on each of the four first failure determination command patterns is the first threshold value. If it is less than, it is determined that an open failure related to at least two of the four switching elements has occurred.

Since the first failure determination command patterns P3 and P4 both command the switching elements of the upper arm and the lower arm in the same leg to be turned off and forcibly short-circuit them, the first failure determination is made. When the detected value of the current acquired by the current acquisition unit 12 under the command patterns P1 and P2 is equal to or higher than the first threshold value (that is, a normal value sufficiently larger than zero), the first failure determination command is used. The process of acquiring the current detection value by the current acquisition unit 12 under the patterns P3 and P4 may be omitted.

Subsequently, a case where a short-circuit failure related to the switching element in the single-phase power conversion device 2 is detected by using the first failure determination command pattern will be described.

When the failure detection device 1 detects a short-circuit failure related to the switching element in the single-phase power conversion device 2, the failure determination unit 13 turns on each switching element in the two first failure determination command patterns PN. Based on the correspondence between the combination of the command and the off command and the detected values of the two currents acquired by the current acquisition unit 12, the location where the short-circuit failure of the single-phase power conversion device 2 occurs is determined.

FIG. 11 shows a failure detection device for detecting a failure of a single-phase power conversion device according to an embodiment of the present disclosure, a switching element in which a short-circuit failure has occurred in a motor drive device including the failure detection device, and a first failure determination command. It is a figure which shows the relationship with a pattern. In FIG. 11, regarding the first failure determination command patterns P1 and P2, the case where the detected value of the current acquired by the current acquisition unit 12 is larger than the second threshold value (that is, the case of indicating an overcurrent) is “x”. , And the case where the value is equal to or less than the second threshold value (that is, the normal value) is indicated by “◯”. Further, in FIG. 11, the case where it is determined that a short _- circuit failure has occurred in _each of the switching elements S1 to S4 is indicated by “x”. The failure determination unit 13 detects a short _- circuit failure of the switching elements S1 to S4 in the _single -phase power conversion device 2 based on the correspondence shown in FIG. It should be noted that the first failure determination command patterns P3 and P4 are related to the switching element because they both command the switching elements of the upper arm and the lower arm in the same leg to be turned off and forcibly short-circuit them. It is not used to determine short faults.

If the switching element S ₄ has a short-circuit failure, the switching element S ₄ remains closed even though the off command remains. When an ON command is given to the switching elements S ₂ and S ₃ under the first failure determination command pattern P2, the switching elements S ₂ and S ₃ are closed, so that the DC side of the bridge circuit of the power conversion device 2 is used. As seen, a short circuit including a switching element S ₂ belonging to the same leg as the positive terminal 25, a switching element S ₄ , and a negative terminal 26 is configured. As a result, when a DC voltage is applied to the DC side of the bridge circuit of the power conversion device 2, an overcurrent flows in the short circuit including the positive electrode terminal 25, the switching element S ₂ , the switching element S ₄ , and the negative electrode terminal 26. Further, if the switching element S ₁ has a short-circuit failure, the switching element S ₁ remains closed even though the off command remains. When an ON command is given to the switching elements S ₂ and S ₃ under the first failure determination command pattern P2, the switching elements S ₂ and S ₃ are closed, so that the DC side of the bridge circuit of the power conversion device 2 is used. As seen, a short circuit including a switching element S ₁ and a switching element S ₃ belonging to the same leg as the positive terminal 25 and a negative terminal 26 is configured. As a result, when a DC voltage is applied to the DC side of the bridge circuit of the power conversion device 2, an overcurrent flows in the short circuit including the positive electrode terminal 25, the switching element S ₁ , the switching element S ₃ , and the negative electrode terminal 26. Further, even if both the switching elements S1 and S4 are short _- circuited, when the DC voltage is applied to the DC side of the bridge circuit of the power conversion device ₂ , the positive electrode terminal 25 and the switching element S are similarly subjected to. An overcurrent flows through a short circuit including ₁ and a switching element S ₃ and a negative electrode terminal 26, and a short circuit including a positive electrode terminal 25, a switching element S ₂ , a switching element S ₃ and a negative electrode terminal 26. The same can be said for the other first failure determination command pattern and the switching element. Therefore, in one embodiment of the present disclosure, the occurrence of a short-circuit failure is detected based on the occurrence of this overcurrent. A second threshold value (for example, about 1.2 times the rated value) larger than the normal value (for example, the rated value) is set in advance and stored in the failure determination unit 13. Whether or not the detected value of the current acquired by the current acquisition unit 12 indicates an overcurrent may be determined based on the comparison result between the detected value of the current acquired by the current acquisition unit 12 and the second threshold value. That is, the failure determination unit 13 determines that the current detection value acquired by the current acquisition unit 12 indicates an overcurrent when the current detection value acquired by the current acquisition unit 12 is larger than the second threshold value. do.

The current detection unit 23 detects this overcurrent via the probe T ₃ . The overcurrent detection value acquired from the current detection unit 23 is acquired by the current acquisition unit 12. Among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 and P2, the first failure determination When the detected value of the current acquired by the current acquisition unit under the command pattern P2 is larger than the second threshold value (when an overcurrent is indicated), the failure determination unit 13 is turned on in the first failure determination command pattern P2. It is assumed that a short-circuit failure related to one of the two switching elements S ₄ and S ₁ to which the command was ordered to be turned off has occurred in the leg to which the switching elements S ₂ and S ₃ to which the command was commanded belong. judge. That is, in this case, the failure determination unit 13 determines that either a short failure related to the switching element S ₄ or a short failure related to the switching element S ₁ has occurred.

Similarly, for example, among the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 and P2. When the detected value of the current acquired by the current acquisition unit under the first failure determination command pattern P1 is larger than the second threshold value (when an overcurrent is indicated), the failure determination unit 13 is used for the first failure determination. A short-circuit failure related to one of the two switching elements S ₃ and S ₂ to which the on command was commanded in the command pattern P1 to be turned off in the leg to which each of the switching elements S ₁ and S ₄ to which the on command was commanded belongs. Judge that it has occurred. That is, in this case, the failure determination unit 13 determines that either a short failure related to the switching element S ₃ or a short failure related to the switching element S ₂ has occurred.

Further, for example, all the detected values of the current on the DC side of the bridge circuit acquired by the current acquisition unit 12 when each switching element is operated based on each of the first failure determination command patterns P1 and P2 are the second. When it is larger than the threshold value of, the two switching elements S ₃ and S, which are instructed to be off in the legs to which the switching elements S ₁ and S ₄ to which the on command is instructed in the first failure determination command pattern P1 belong, respectively. There is a possibility that a short failure related to any of ₂ has occurred, and in the leg to which each of the switching elements S ₂ and S ₃ to which the on command was commanded in the first failure determination command pattern P2 belongs. The possibility of a short failure related to one of the two switching elements S ₄ and S ₁ that were instructed to be off, respectively, and related to the switching elements S ₁ , S ₂ , S ₃ and S ₄ . There is a possibility that a short failure has occurred. Of these, when short-circuit failures of switching elements S ₁ and S ₃ in the same leg occur at the same time, or when short-circuit failures of switching elements S ₂ and S ₄ in the same leg occur at the same time, the power conversion device 2 Since the DC side of the power converter 2 is already short-circuited, the power conversion device 2 does not operate in the first place, that is, "the power conversion device 2 does not operate" is related to the switching elements S ₁ , S ₂ , S ₃ and S ₄ . The operator can grasp that a short-circuit failure has occurred, and it is not necessary to execute the failure detection process by the failure detection device 1. Therefore, short failures related to the switching elements S ₁ , S ₂ , S ₃ and S ₄ are excluded from the short failure detection target of the failure detection device 1. In the failure determination unit 13, a short failure related to the switching element occurs in all of the switching elements S ₁ and S ₂ in the upper arm of the bridge circuit or in all of the switching elements S ₃ and S ₄ in the lower arm of the bridge circuit. Try to determine that it is.

As described above, the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 including the failure detection device 1 can detect an open failure or a short failure related to the switching element.

Subsequently, an example of detecting a failure of the current detection unit 23 in the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 including the failure detection device 1 will be described.

FIG. 12 is a diagram showing the relationship between the current flowing through the switching element in the bridge circuit of the power conversion device and the on-time of the switching element.

A load circuit 3 for failure detection is connected to the AC side of the power conversion device 2, and a DC power supply for failure detection is connected to the DC side of the power conversion device 2, and a DC voltage is applied. When the switching element is turned on over Δt from time t ₁ to time t ₂ according to any one of the failure determination command patterns of 1, the switching element and the load circuit 3 are arranged according to the passage of the on time (gate voltage application time). The current flowing through the closed circuit, including, gradually increases. The load circuit 3 is an inductive load or a resistant load, such as an AC motor, a reactor, and a resistor. When Kirchhoff's law is applied to a closed circuit including a switching element and a load circuit 3, an estimated value I _est of the current flowing through the switching element at the time t ₂ at which the switching element is turned on as represented by Equation 1 is obtained. Be done. In Equation 1, the voltage detection value detected by the voltage detection unit 24 is V _dc , the on-time of the switching element is Δt, the resistance component of the impedance of the load circuit 3 is R, and the inductance component is L.

The impedance of the load circuit 3 is acquired in advance and stored in the storage unit in the current estimation unit 15. Further, the current estimation unit 15 acquires the detected value of the voltage detected by the voltage detection unit 24 from the voltage acquisition unit 14. Further, the current estimation unit 15 acquires information on the on-time of the switching element from the first failure determination command pattern generated by the command generation unit 11. In the three-phase power conversion device 2, information regarding the on-time of the six switching elements can be acquired by using any one of the six first failure determination command patterns. Similarly, in the single-phase power conversion device 2, information regarding the on-time of the four switching elements can be acquired by using any one of the four first failure determination command patterns. The current estimation unit 15 determines the current flowing through each switching element based on the voltage detection value V _dc acquired by the voltage acquisition unit 14, the time Δt in which the switching element is instructed to be turned on, and the impedance of the load circuit 3. Calculate the estimated value I _est . The calculated estimated value of the current flowing through each switching element is sent to the failure determination unit 13.

A load circuit 3 for failure detection is connected to the AC side of the power conversion device 2, and a DC power supply for failure detection is connected to the DC side of the power conversion device 2 to apply a DC voltage. The current flowing through the switching element when the switching element is turned on according to the failure determination command pattern of 1 is the same as the current detected by the current detection unit 23 via the probes T ₁ , T ₂ or T ₃ . .. If each part in the power conversion device 2 is functioning normally, the current detection value detected by the current detection unit 23 is substantially the same as the current estimation value I _est calculated by the current estimation unit 15. On the other hand, when some abnormality occurs in the power conversion device 2, a deviation occurs between the current detection value detected by the current detection unit 23 and the current estimation value I _est calculated by the current estimation unit 15. Failures that can occur in the power conversion device 2 include, for example, an open failure related to the switching element, a short failure related to the switching element, and a failure related to the current detection unit 23 provided in the power conversion device 2. If these open failures and short failures are not detected even though the open failure and short failure determination processes related to the switching element have been performed, it is considered that the current detection unit 23 has failed.

Therefore, the failure determination unit 13 first determines the current estimation value I _est calculated by the current estimation unit 15 as the current detection value detected by the current detection unit 23 under the plurality of first failure determination command patterns. By comparison, it is determined whether or not there is a discrepancy between the detected current value and the estimated current value I _est . Whether or not there is a discrepancy between the current detected value and the current estimated value I _est is whether or not the difference between the current detected value and the current estimated value is out of the predetermined range, or whether or not the current is detected. The determination may be made based on whether or not the ratio between the value and the estimated value of the current is out of the predetermined range. For example, if the difference between the detected current value and the estimated current value is outside the specified range (for example, if it does not fall within the range of ± several amperes), it is determined that the detected current value deviates from the estimated current value. .. Further, for example, when the ratio between the detected current value and the estimated current value (the value obtained by dividing the detected current value by the estimated current value) is out of the predetermined range (for example, it does not fall within the range of 80% to 120%). Case), it is determined that the detected value of the current deviates from the estimated current. It should be noted that the numerical values given here are merely examples, and other numerical values may be used. When the failure determination unit 13 determines that there is a discrepancy between the current detection value and the current estimated value I _est , the failure determination unit 13 next determines whether or not an open failure or short failure related to the switching element has occurred. judge. Then, if the open failure and the short failure are not detected, the failure determination unit 13 determines that a failure related to the current detection unit 23 has occurred. For example, when an open failure and a short failure are not detected under the first failure determination command pattern P1 shown in FIG. 2, the probes T ₁ or T ₃ provided in the current path including the switching element S ₁ are used. It can be identified that it was out of order. For example, when neither an open failure nor a short failure is detected under the first failure determination command patterns P1, P2, P4 and P5 shown in FIG. 2, the current path including the switching element S ₁ is provided. It can be identified that the probe T ₁ or T ₃ to be mounted has failed. Further, for example, when neither an open failure nor a short failure is detected under the first failure determination command patterns P1, P3, P4 and P6 shown in FIG. 2, the current path including the switching element S ₁ is used. It can be identified that the provided probe T ₂ or T ₃ has failed.

FIG. 13 shows a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure, an open failure and a short-circuit failure related to a switching element in a motor drive device including the failure detection device, and a failure of a current detection unit. It is a flowchart which shows the detection process. Here, as an example, the failure detection processing for the three-phase power conversion device 2 will be described, but this description describes the single-phase power conversion device 2 by changing the maximum value of the identification number N from 6 to 4. It can also be applied to the failure detection processing of.

In the open failure and short-circuit failure related to the switching element in the failure detection device 1 and the motor drive device 100 including the failure detection device 1 and the detection process of the current detection unit, a DC voltage is applied to the DC side of the three-phase power conversion device 2 and power is applied. This is executed with the load circuit 3 connected to the AC side of the conversion device 2.

First, in step S301, the command generation unit 11 sets the identification number N of the first failure determination command pattern to 1 as an initial setting. The setting of the identification number N of the first failure determination command pattern in step S301 may be performed, for example, by an input operation using an input device to the failure detection device 1 of the operator, or the failure detection device. It may be automatically performed at the start of the failure detection process according to 1, or may be automatically performed when the power of the failure detection device 1 is turned on.

In step S302, the command generation unit 11 commands the switching control unit 21 for the first failure determination command pattern PN. The switching control unit 21 generates an on command and an off command for each switching element based on the first failure determination command pattern PN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. The first failure determination command pattern PN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S303, the current acquisition unit 12 acquires the current detection value by the current detection unit 23 corresponding to the first failure determination command pattern PN. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13. The failure determination unit 13 stores the detected value of the current sent from the current acquisition unit 12 in association with the first failure determination command pattern PN used when acquiring the detected value of the current. do.

In step S304, the voltage acquisition unit 14 acquires the detected value of the voltage on the DC side of the power conversion device detected by the voltage detection unit 24. The detected value of the acquired voltage is sent to the current estimation unit 15.

In step S305, the detection value of the voltage acquired by the voltage acquisition unit 14 in step S304, the time when the switching element is on-commanded according to the first failure determination command pattern PN in step S302, and the impedance of the load circuit 3. Based on, the estimated value of the current flowing through each switching element is calculated. The calculated estimated value of the current is sent to the failure determination unit 13.

In step S306, the command generation unit 11 determines whether or not the identification number N of the first failure determination command pattern PN is 6. If it is determined that the identification number N of the first failure determination command pattern PN is 6, the process proceeds to step S308, and it is not determined that the identification number N of the first failure determination command pattern PN is 6. In that case, the process proceeds to step S307. In the example shown in FIG. 13, the failure detection processing for the three-phase power conversion device 2 has been described as an example. Therefore, in step S306, “the identification number N of the first failure determination command pattern PN is 6. "Whether or not" was determined, but in the case of failure detection processing for the single-phase power conversion device 2, "whether or not the identification number N of the first failure determination command pattern PN is 4" is determined. You just have to judge.

In step S307, the command generation unit 11 increments the identification number N of the first failure determination command pattern PN by one. After that, the process returns to step S302.

In step S308, the failure determination unit 13 has a ratio (that is,) between each of the six current detection values acquired by the current acquisition unit 12 and each of the six current estimation values calculated by the corresponding current estimation unit 15. It is determined whether or not the ratio between the detected value of at least one current and the estimated current value among the detected value of the current divided by the estimated current value is out of the predetermined range. If it is determined that the ratio between the detected current value and the estimated current value is within the predetermined range, the process proceeds to step S309, and the ratio between the detected current value and the estimated current value is within the predetermined range. If is not determined, the process proceeds to step S310. In step S308, the "difference between the detected current value and the estimated current" may be used for the determination process instead of the "ratio of the detected current and the estimated current".

In step S309, the failure determination unit 13 outputs a determination result that the power conversion device 2 is normal, and ends the process.

In step S310, the failure determination unit 13 determines whether or not an open failure related to the switching element has occurred. If it is determined that an open failure has occurred, the process proceeds to step S311. If it is not determined that an open failure has occurred, the process proceeds to step S312. The details of the open failure determination process are as described with reference to FIGS. 1 to 5.

In step S311, the failure determination unit 13 outputs information regarding the switching element in which the open failure has occurred, and ends the process.

In step S312, the failure determination unit 13 determines whether or not a short-circuit failure related to the switching element has occurred. If it is determined that a short failure has occurred, the process proceeds to step S313, and if it is not determined that a short failure has occurred, the process proceeds to step S314. The details of the short-circuit failure determination process are as described with reference to FIGS. 1 to 4 and 6.

In step S313, the failure determination unit 13 outputs information regarding the switching element in which the short-circuit failure has occurred, and ends the process.

The order of the open failure determination and the short failure determination in steps S310 to S314 may be changed.

In step S314, the failure determination unit 13 outputs a determination that a failure has occurred to the current detection unit 23 provided in the power conversion device 2, and ends the process.

As described above, according to the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 provided with the failure detection device 1, the switching element in the three-phase power conversion device 2 is used by using the first failure determination command pattern. It is possible to quickly and accurately detect the location and details of an open failure, a short-circuit failure, and a failure of the current detection unit related to the above.

Subsequently, a case of detecting a failure of the overcurrent detection unit provided corresponding to each of the switching elements in the three-phase power conversion device 2 shown in FIG. 1 will be described.

As the drive circuit 22, a driver IC having an overcurrent detection function called a DESAT detection circuit may be used. The DESAT detection circuit is provided for each switching element. Further, the power element including the switching element and the diode can be configured by the IPM having the overcurrent detection function. As described above, in both the DESAT detection circuit and the IPM, an overcurrent detection unit is provided for each switching element, but this overcurrent detection unit may also fail for some reason. In one embodiment of the present disclosure, a failure of the overcurrent detection unit is detected by using a second failure determination command pattern including a combination of an on command and an off command.

FIG. 14 shows a second failure determination command used for detecting a failure of the overcurrent detection unit provided corresponding to each of the switching elements in the three-phase power conversion device according to the embodiment of the present disclosure. It is a figure which shows the pattern.

Six different commands are used as a second failure determination command pattern for detecting a failure of the overcurrent detection unit provided corresponding to each of the switching elements in the three-phase power conversion device 2 shown in FIG. The pattern is generated by the command generation unit 11. Each of the six second failure determination command patterns is identified using the identification number N (where N is a natural number from 1 to 6). Each of the six second failure determination command patterns QN is the switching element of any one of the upper or lower arms constituting the bridge circuit and the relevant leg in a leg different from the leg to which the arm belongs. It consists of a combination of an on command for a switching element of an arm on a side different from the arm and an off command for a switching element other than the on-commanded switching element. More details are as follows.

The second failure determination command pattern Q1 is an _on -command for the switching element S1 of the upper arm constituting the bridge circuit and the switching elements _S5 and S6 of the lower arm in a leg different from the _leg to which the upper arm belongs. It consists of a combination of and an off command for switching elements S ₂ , S ₃ and S ₄ other than the on-commanded switching elements S ₁ , S ₅ and S ₆ .

The second failure determination command pattern Q2 is an on-command for the switching element S ₂ of the upper arm constituting the bridge circuit and the switching elements S ₄ and S ₆ of the lower arm in a leg different from the leg to which the upper arm belongs. It is composed of a combination of an on command and an off command for switching elements S ₁ , S ₃ and S ₅ other than the switching elements S ₂ , S ₄ and S ₆ instructed to be on.

The second failure determination command pattern Q3 is an on-command for the switching element S ₃ of the upper arm constituting the bridge circuit and the switching elements S ₄ and S ₅ of the lower arm in a leg different from the leg to which the upper arm belongs. It consists of a combination of and an off command for switching elements S ₁ , S ₂ and S ₆ other than the on-commanded switching elements S ₃ , S ₄ and S ₅ .

The second failure determination command pattern Q4 is an on-command for the lower arm switching element S ₄ constituting the bridge circuit and the lower arm switching elements S ₂ and S ₃ in a leg different from the leg to which the upper arm belongs. It consists of a combination of and an off command for switching elements S ₁ , S ₅ and S ₆ other than the on-commanded switching elements S ₂ , S ₃ and S ₄ .

The second failure determination command pattern Q5 is an on-command for the lower arm switching element S ₅ constituting the bridge circuit and the lower arm switching elements S ₁ and S ₃ in a leg different from the leg to which the upper arm belongs. It consists of a combination of and an off command for switching elements S ₂ , S ₄ and S ₆ other than the on-commanded switching elements S ₁ , S ₃ and S ₅ .

The second failure determination command pattern Q6 is an on-command for the lower arm switching element S ₆ constituting the bridge circuit and the lower arm switching elements S ₁ and S ₂ in a leg different from the leg to which the upper arm belongs. It consists of a combination of and an off command for switching elements S ₃ , S ₄ and S ₅ other than the on-commanded switching elements S ₁ , S ₂ and S ₆ .

FIG. 15 shows a failure of the overcurrent detection unit provided corresponding to each of the failure detection device for detecting the failure of the three-phase power conversion device according to the embodiment of the present disclosure and the switching element in the motor drive device including the failure detection device. It is a flowchart which shows the detection process of.

In the failure detection process of the overcurrent detection unit provided corresponding to each of the failure detection device 1 and the switching element in the motor drive device 100 including the failure detection device 1, a DC voltage is applied to the DC side of the three-phase power conversion device 2. It is executed in a state where the load circuit 3 is connected to the AC side of the power conversion device 2.

First, in step S401, the command generation unit 11 sets the identification number N of the second failure determination command pattern to 1 as an initial setting. The setting of the identification number N of the second failure determination command pattern in step S401 may be performed, for example, by an input operation using an input device to the failure detection device 1 of the operator, or the failure detection device. It may be automatically performed at the start of the failure detection process according to 1, or may be automatically performed when the power of the failure detection device 1 is turned on.

In step S402, the command generation unit 11 commands the switching control unit 21 for the second failure determination command pattern QN. The switching control unit 21 generates an on command and an off command for each switching element based on the second failure determination command pattern QN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. Since a DC voltage is applied to the DC side of the three-phase power conversion device 2 and a load circuit 3 is connected to the AC side of the power conversion device 2, three of the six switching elements are switched on. A closed circuit is formed at the positive current terminal 25 on the DC side of the power conversion device 2, the load circuit 3, and the negative negative terminal 26 on the DC side of the power conversion device 2 via the element. The second failure determination command pattern QN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S403, the current acquisition unit 12 determines whether or not an overcurrent has flowed in the on-commanded switching element as information regarding the detected value of the current flowing in the on-commanded switching element according to the second failure determination command pattern QN. Get the information that indicates. For example, when the current acquisition unit 12 acquires the detected value of the current flowing through the switching element itself from the current detection unit 23, the overcurrent is overcurrent when the detected value of the current is larger than the third threshold value (overcurrent detection level). Generates information indicating that the child has flowed, and when the detected value of the current is equal to or less than the third threshold value (overcurrent detection level), information indicating that no overcurrent has flowed is generated. Further, for example, when a driver IC having an overcurrent detection function called a DESAT detection circuit is used as the drive circuit 22, the ON-commanded switching element is transmitted from the DESAT detection circuit corresponding to the ON-commanded switching element. As information on the detected value of the current flowing through the circuit, information indicating whether or not an overcurrent has flowed is acquired. Further, for example, when a power element composed of a switching element and a diode is configured by an IPM, an overcurrent is detected as a detection value of a current flowing from the IPM related to the on-commanded switching element to the on-commanded switching element. Acquires information indicating whether or not it has flowed. Information regarding the detected value of the current acquired by the current acquisition unit 12 (information indicating whether or not an overcurrent has flowed) is sent to the failure determination unit 13. The failure determination unit 13 is used when acquiring the information regarding the detected value of the current sent from the current acquisition unit 12 (information indicating whether or not an overcurrent has flowed) and the detected value of the current. It is stored in association with the failure determination command pattern QN of 2.

In step S404, the command generation unit 11 determines whether or not the identification number N of the second failure determination command pattern QN is 6. If it is determined that the identification number N of the second failure determination command pattern QN is 6, the process proceeds to step S406, and it is not determined that the identification number N of the second failure determination command pattern QN is 6. In the case, the process proceeds to step S405.

In step S405, the command generation unit 11 increments the identification number N of the second failure determination command pattern QN by one. Then, the process returns to step S402.

In step S406, the failure determination unit 13 provides information regarding the combination of the on command and the off command for each switching element in the second failure determination command pattern QN and the detected value of the current acquired by the current acquisition unit 12 (overcurrent flows). Based on the correspondence with the information indicating whether or not the current is present), the location where the failure of the overcurrent detection unit provided corresponding to each of the switching elements in the three-phase power conversion device 2 occurs (that is, which switching element). Whether the corresponding overcurrent detector is out of order) is determined. After that, a series of failure detection processes are terminated.

Here, the failure determination process of the overcurrent detection unit in step S406 will be described in more detail.

FIG. 16 is a diagram illustrating a closed circuit formed when a second failure determination command pattern is commanded to a switching element in a three-phase power conversion device according to an embodiment of the present disclosure. As an example, FIG. 16 illustrates a closed circuit that can be formed when a first failure determination command pattern Q1 is commanded to each switching element. In FIG. 16, the failure detection device 1 is not shown.

As shown in FIG. 16, in a state where a DC voltage is applied to the DC side of the three-phase power conversion device 2 and the load circuit 3 is connected to the AC side of the power conversion device 2, a second failure determination command pattern is used. In Q1, the switching element S ₁ of the upper arm and the switching elements S ₅ and S ₆ of the lower arm in a leg different from the leg to which the upper arm belongs are on-commanded, and the on-commanded switching element S ₁ , Off command is given to switching elements S ₂ , S ₃ and S ₄ other than S ₅ and S ₆ . As a result, under the second failure determination command pattern Q1, a closed circuit including a positive electrode terminal 25, a switching element S ₁ , a load circuit 3, a switching element S ₅ , and a negative electrode terminal 26 (hereinafter, “first closed circuit”). A circuit (referred to as "circuit") and a closed circuit (hereinafter referred to as "second closed circuit") including a positive electrode terminal 25, a switching element S ₁ , a load circuit 3, a switching element S ₆ , and a negative electrode terminal 26 are formed. To. If all six switching elements are functioning normally (ie, neither open failure nor short failure has occurred), they are commonly included in the first closed circuit and the second closed circuit. The switching element S ₁ should have about twice the current flowing through each of the switching element S ₅ included only in the first closed circuit and the switching element S ₆ included only in the second closed circuit. .. For example, the overcurrent detection of the overcurrent detection unit provided corresponding to the switching element _S1 between the value of the current flowing through the switching element S1 and the value of the current flowing through the _switching element _S5 or the switching element _S6 . When the level is set, the value of the current flowing through the switching element S1 by operating each switching element under the second failure determination command pattern _Q1 exceeds the overcurrent detection level, so that the switching element S If the overcurrent detection unit provided corresponding to ₁ is functioning normally, the occurrence of overcurrent can be detected. _On the _other hand, the overcurrent detection of the overcurrent detection unit provided corresponding to the switching element S1 between the value of the current flowing through the switching element S1 and the value of the current flowing through the switching element _S5 or the switching element _S6 . Even if the level is set, when the overcurrent detection unit is out of order, it is possible to determine that "the value of the current flowing through the switching element S ₁ exceeds the overcurrent detection level". Can not. The _same can be said for each of the switching elements S2 to S6 even when each switching element is operated under each of the _second failure determination command patterns Q2 to Q6. Therefore, in the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 including the failure detection device 1, the failure of the overcurrent detection unit provided for each switching element is detected by utilizing the above-mentioned properties. More details are as follows.

The overcurrent detection level of the overcurrent detection unit is set as a third threshold value. Further, the value of the current flowing through the switching element commonly included in the first closed circuit and the second closed circuit, and the switching included only in the first closed circuit or the switching element included only in the second closed circuit. The value of the DC voltage to be applied from the DC side of the bridge circuit of the power converter 2 and the bridge so that a third threshold value (that is, the overcurrent detection level) exists between the value of the current flowing through the element. Adjust each value of the impedance of the load circuit 3 to be connected to the AC side of the circuit in advance. Alternatively, when the load circuit 3 is an inductive load (for example, an AC motor or a reactor), it is also commonly included in the first closed circuit and the second closed circuit by adjusting the on-time of the switching element. A third threshold (ie, overcurrent) is between the value of the current flowing through the switching element and the value of the current flowing through the switching element contained only in the first closed circuit or the switching element contained only in the second closed circuit. It can also be adjusted so that the detection level) is set.

Further, the current detection unit 23 is configured to be able to detect the current flowing through each switching element, and the current acquisition unit 12 acquires the current detection value by the current detection unit 23. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13.

The failure determination unit 13 passes the on-commanded switching element based on the information acquired by the current acquisition unit 12 when each switching element is operated under each of the second failure determination command patterns Q1 to Q6. Determine if there is any current flowing through it. Whether or not there is an overcurrent flowing through the switching element may be determined based on the comparison result between the current detection value acquired by the current acquisition unit 12 and the third threshold value (overcurrent detection level). That is, the failure determination unit 13 determines that the current detection value acquired by the current acquisition unit 12 indicates an overcurrent when the current detection value acquired by the current acquisition unit 12 is larger than the third threshold value. do.

For example, when the drive circuit 22 is composed of a DESAT detection circuit, the current acquisition unit 12 may acquire information indicating whether or not an overcurrent has flowed to the switching element via the drive circuit 22. Further, for example, when a power element composed of a switching element and a diode is configured by an IPM, the current acquisition unit 12 uses the overcurrent detection function of the IPM to provide information indicating whether or not an overcurrent has flowed through the switching element. You may get it. In any of these cases, the failure determination unit 13 uses the "information indicating whether or not an overcurrent has flowed in the switching element" acquired by the current acquisition unit 12 for the failure determination of the overcurrent detection unit.

When the failure determination unit 13 determines that there is a switching element in which an overcurrent has flowed, the switching determined that an overcurrent has flowed among the switching elements instructed to be on under the second failure determination command pattern. The overcurrent detector corresponding to the element is determined to be normal.

FIG. 17 shows the relationship between the failure detection device for detecting the failure of the three-phase power conversion device according to the embodiment of the present disclosure, the overcurrent detection unit in the motor drive device including the failure detection device, and the second failure determination command pattern. It is a figure which shows. In FIG. 17, with respect to the second failure determination command patterns Q1 to Q6, when an overcurrent has flowed through the switching element instructed to be turned on (a third threshold value is set in the detected value of the current acquired by the current acquisition unit 12). (When there is a larger one) is indicated by "○", and when no overcurrent flows in any of the switching elements instructed to be turned on (the detected value of the current acquired by the current acquisition unit 12 is the third threshold value). (In the following cases) is indicated by "x". Further, in FIG. 17, for _each of the switching elements S1 to _S6 , the switching element determined to have a failure in the corresponding overcurrent detection unit is indicated by “x”. The failure determination unit 13 detects a failure of the overcurrent detection unit provided corresponding to the switching elements S1 to S6 in the _{three -} phase power conversion device 2 based on the correspondence relationship shown in FIG.

For example, for all of the second failure determination command patterns Q1 to Q6, when an overcurrent has flowed through the switching element instructed to be turned on (current acquisition under the second failure determination command patterns Q1 to Q6). (When all the current detection values acquired by the unit 12 are larger than the third threshold value), the failure determination unit ₁₃ has normal overcurrent detection units corresponding to _each of the switching elements S1 to S6. Is determined to be.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q1 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q1). (When none of the detected currents is larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₁ has failed.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q2 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q2). (When there is no current detection value larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₂ has failed.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q3 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q3). (When there is no current detection value larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₃ has failed.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q4 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q4). (When there is no current detection value larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₄ has failed.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q5 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q5). (When there is no current detection value larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₅ has failed.

For example, when no overcurrent has flowed in the switching element instructed to be turned on under the second failure determination command pattern Q6 (acquired by the current acquisition unit 12 under the second failure determination command pattern Q6). (When there is no current detection value larger than the third threshold value), the failure determination unit 13 determines that the overcurrent detection unit provided corresponding to the switching element S ₆ has failed.

As described above, according to the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 provided with the failure detection device 1, the switching element in the three-phase power conversion device 2 is used by using the second failure determination command pattern. It is possible to quickly and accurately detect the location where a failure occurs in the overcurrent detection unit provided in response to the above.

18 to 20 show an open failure, a short-circuit failure, and a current detection unit related to a failure detection device for detecting a failure of a three-phase power conversion device according to an embodiment of the present disclosure and a switching element in a motor drive device including the failure detection device. It is a flowchart which shows the failure detection process of the failure, and the failure of the overcurrent detection unit provided corresponding to the switching element.

The detection processing of the open failure and short-circuit failure related to the switching element in the failure detection device 1 and the motor drive device 100 including the failure detection device 1, the failure of the current detection unit 23, and the failure of the overcurrent detection unit provided corresponding to the switching element is performed. , The DC voltage is applied to the DC side of the three-phase power conversion device 2, and the load circuit 3 is connected to the AC side of the power conversion device 2.

First, in step S501, the command generation unit 11 sets the identification number N of the first failure determination command pattern to 1 as an initial setting. The setting of the identification number N of the first failure determination command pattern in step S501 may be performed, for example, by an input operation using an input device to the failure detection device 1 of the operator, or the failure detection device. It may be automatically performed at the start of the failure detection process according to 1, or may be automatically performed when the power of the failure detection device 1 is turned on.

In step S502, the command generation unit 11 commands the switching control unit 21 for the first failure determination command pattern PN. The switching control unit 21 generates an on command and an off command for each switching element based on the first failure determination command pattern PN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. The first failure determination command pattern PN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S503, the current acquisition unit 12 acquires the current detection value by the current detection unit 23 corresponding to the first failure determination command pattern PN. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13. The failure determination unit 13 stores the detected value of the current sent from the current acquisition unit 12 in association with the first failure determination command pattern PN used when acquiring the detected value of the current. do.

In step S504, the voltage acquisition unit 14 acquires the detected value of the voltage on the DC side of the power conversion device detected by the voltage detection unit 24. The detected value of the acquired voltage is sent to the current estimation unit 15.

In step S505, the detection value of the voltage acquired by the voltage acquisition unit 14 in step S504, the time when the switching element is on-commanded according to the first failure determination command pattern PN in step S502, and the impedance of the load circuit 3. Based on, the estimated value of the current flowing through each switching element is calculated. The calculated estimated value of the current is sent to the failure determination unit 13.

In step S506, the command generation unit 11 determines whether or not the identification number N of the first failure determination command pattern PN is 6. If it is determined that the identification number N of the first failure determination command pattern PN is 6, the process proceeds to step S508, and it is not determined that the identification number N of the first failure determination command pattern PN is 6. If so, the process proceeds to step S507.

In step S507, the command generation unit 11 increments the identification number N of the first failure determination command pattern PN by one. Then, the process returns to step S502.

In step S508, the failure determination unit 13 has a ratio (that is,) between each of the six current detection values acquired by the current acquisition unit 12 and each of the six current estimation values calculated by the corresponding current estimation unit 15. It is determined whether or not the ratio between the detected value of at least one current and the estimated current value among the detected value of the current divided by the estimated current value is out of the predetermined range. If it is determined that the ratio between the detected current value and the estimated current value is within the predetermined range, the process proceeds to step S509, and the ratio between the detected current value and the estimated current value is within the predetermined range. If is not determined, the process proceeds to step S514. In step S509, the "difference between the detected current value and the estimated current" may be used for the determination process instead of the "ratio of the detected current and the estimated current".

In step S509, the failure determination unit 13 determines whether or not an open failure related to the switching element has occurred. If it is determined that an open failure has occurred, the process proceeds to step S510, and if it is not determined that an open failure has occurred, the process proceeds to step S511. The details of the open failure determination process are as described with reference to FIGS. 1 to 5.

In step S510, the failure determination unit 13 outputs information regarding the switching element in which the open failure has occurred, and ends the process.

In step S511, the failure determination unit 13 determines whether or not a short-circuit failure related to the switching element has occurred. If it is determined that a short failure has occurred, the process proceeds to step S512, and if it is not determined that a short failure has occurred, the process proceeds to step S513. The details of the open failure determination process are as described with reference to FIGS. 1 to 4 and 6.

In step S512, the failure determination unit 13 outputs information about the switching element in which the short-circuit failure has occurred, and ends the process.

The order of the open failure determination and the short failure determination in steps S509 to S512 may be changed.

In step S513, the failure determination unit 13 outputs a determination that a failure has occurred to the current detection unit 23 provided in the power conversion device 2, and ends the process.

In step S514, the command generation unit 11 sets the identification number N of the second failure determination command pattern to 1.

In step S515, the command generation unit 11 commands the switching control unit 21 for the second failure determination command pattern QN. The switching control unit 21 generates an on command and an off command for each switching element based on the second failure determination command pattern QN received from the command generation unit 11. The generated on-command and off-command are sent to the drive circuit 22. The drive circuit 22 applies a gate voltage to each switching element to turn on / off the switching element in response to the on command and the off command. Since a DC voltage is applied to the DC side of the three-phase power conversion device 2 and a load circuit 3 is connected to the AC side of the power conversion device 2, three of the six switching elements are commanded to be switched on. A closed circuit is formed at the positive current terminal 25 on the DC side of the power conversion device 2, the load circuit 3, and the negative negative terminal 26 on the DC side of the power conversion device 2 via the element. The second failure determination command pattern QN generated by the command generation unit 11 is also sent to the failure determination unit 13.

In step S516, the current acquisition unit 12 indicates whether an overcurrent has occurred in the on-commanded switching element as information regarding the detected value of the current flowing through the on-commanded switching element according to the second failure determination command pattern QN. Obtain information indicating whether or not. For example, when the current acquisition unit 12 acquires the detected value of the current flowing through the switching element itself from the current detection unit 23, the overcurrent is overcurrent when the detected value of the current is larger than the third threshold value (overcurrent detection level). Generates information indicating that the child has flowed, and when the detected value of the current is equal to or less than the third threshold value (overcurrent detection level), information indicating that no overcurrent has flowed is generated. Further, for example, when a driver IC having an overcurrent detection function called a DESAT detection circuit is used as the drive circuit 22, the ON-commanded switching element is transmitted from the DESAT detection circuit corresponding to the ON-commanded switching element. As information on the detected value of the current flowing through the circuit, information indicating whether or not an overcurrent has flowed is acquired. Further, for example, when a power element composed of a switching element and a diode is configured by an IPM, the information regarding the detected value of the current flowing from the IPM related to the on-commanded switching element to the on-commanded switching element is excessive. Acquires information indicating whether or not a current has flowed. The detected value of the current acquired by the current acquisition unit 12 is sent to the failure determination unit 13. The failure determination unit 13 stores the detected value of the current sent from the current acquisition unit 12 in association with the second failure determination command pattern QN used when acquiring the detected value of the current. do.

In step S517, the command generation unit 11 determines whether or not the identification number N of the second failure determination command pattern QN is 6. If it is determined that the identification number N of the second failure determination command pattern QN is 6, the process proceeds to step S519, and it is not determined that the identification number N of the second failure determination command pattern QN is 6. If so, the process proceeds to step S518.

In step S518, the command generation unit 11 increments the identification number N of the second failure determination command pattern QN by one. Then, the process returns to step S515.

In step S519, the failure determination unit 13 provides information regarding the combination of the on command and the off command for each switching element in the second failure determination command pattern QN and the detection value of the current acquired by the current acquisition unit 12 (overcurrent flows). Based on the correspondence with the information indicating whether or not the current is present), it is determined whether or not a failure has occurred in the overcurrent detection unit provided corresponding to each of the switching elements in the three-phase power conversion device 2. If it is determined that a failure of the overcurrent detection unit has occurred, the process proceeds to step S520, and if it is not determined that a failure of the overcurrent detection unit has occurred, the process proceeds to step S521. The details of the failure determination process of the overcurrent detection unit are as described with reference to FIGS. 14 to 17.

In step S520, the failure determination unit 13 outputs information regarding the failure of the overcurrent detection unit and ends the process.

In step S521, the failure determination unit 13 outputs a determination result that the power conversion device 2 is normal, and ends the process.

As described above, according to the failure detection device 1 according to the embodiment of the present disclosure and the motor drive device 100 provided with the failure detection device 1, the switching element in the three-phase power conversion device 2 is used by using the first failure determination command pattern. It is possible to quickly and accurately detect the location and details of the failure of the open failure and short-circuit failure, the failure of the current detection unit, and the failure of the overcurrent detection unit related to the above.

The above-mentioned command generation unit 11, current acquisition unit 12, failure determination unit 13, voltage acquisition unit 14, current estimation unit 15, switching control unit 21, drive circuit 22, and higher-level control unit (not shown) are arithmetic processing devices. It may be composed of only an analog circuit, it may be composed of a combination of an analog circuit and an arithmetic processing device, or it may be composed of only an analog circuit. An arithmetic processing unit that can configure a command generation unit 11, a current acquisition unit 12, a failure determination unit 13, a voltage acquisition unit 14, a current estimation unit 15, a switching control unit 21, a drive circuit 22, and an upper control unit (not shown). Examples include ICs, LSIs, CPUs, MPUs, DSPs, and the like. For example, the command generation unit 11, the current acquisition unit 12, the failure determination unit 13, the voltage acquisition unit 14, the current estimation unit 15, the switching control unit 21, the drive circuit 22, and the upper control unit (not shown) are in software program format. When constructing, by operating the arithmetic processing device according to this software program, the command generation unit 11, the current acquisition unit 12, the failure determination unit 13, the voltage acquisition unit 14, the current estimation unit 15, the switching control unit 21, and the drive circuit. 22 and each function of the upper control unit (not shown) can be realized. Alternatively, the command generation unit 11, the current acquisition unit 12, the failure determination unit 13, the voltage acquisition unit 14, the current estimation unit 15, the switching control unit 21, the drive circuit 22, and the upper control unit (not shown) are included in each unit. It may be realized as a semiconductor integrated circuit in which a software program that realizes a function is written. Alternatively, the command generation unit 11, the current acquisition unit 12, the failure determination unit 13, the voltage acquisition unit 14, the current estimation unit 15, the switching control unit 21, the drive circuit 22, and the upper control unit (not shown) are included in each unit. It may be realized as a recording medium in which a software program that realizes a function is written. Further, the command generation unit 11, the current acquisition unit 12, the failure determination unit 13, the voltage acquisition unit 14, the current estimation unit 15, the switching control unit 21, the drive circuit 22, and the upper control unit (not shown) are, for example, machine tools. It may be provided in the numerical control device of the above, or may be provided in the robot controller that controls the robot.

The current detection unit 23 and the voltage detection unit 24 may be configured by a combination of an analog circuit and an arithmetic processing device, may be composed of only an arithmetic processing device, or may be composed of only an analog circuit. As the current detection unit 23 and the voltage detection unit 24, those generally provided in the power conversion device 2 or the motor drive device 100 may be diverted.

1 Failure detection device 2 Power conversion device 3 Load circuit 11 Command generation unit 12 Current acquisition unit 13 Failure determination unit 14 Voltage acquisition unit 15 Current estimation unit 21 Switching control unit 22 Drive circuit 23 Current detection unit 24 Voltage detection unit 25 Positive electrode terminal 26 Negative electrode terminal 100 Motor drive

Claims (15)

A failure detection device that detects a failure of a power conversion device that converts DC to AC power or AC to DC power by turning on and off a plurality of switching elements that make up a bridge circuit.
A command generation unit that generates a plurality of command patterns consisting of a combination of an on command and an off command for each of the switching elements, and each of the plurality of command patterns has a different combination of the on command and the off command. Department and
A current acquisition unit that acquires the detected value of the current flowing through the bridge circuit,
Each of the above is a combination of an on command and an off command for each of the switching elements in the command pattern, and a state in which a DC voltage is applied to the DC side of the power conversion device and a load circuit is connected to the AC side of the power conversion device. Failure determination to determine the failure of the power conversion device based on the current detection value acquired by the current acquisition unit when the command pattern is commanded to the switching element to operate each switching element. Department and
A failure detection device. The bridge circuit is a three-phase bridge circuit.
The command generation unit, as each of the six command patterns, has the switching element of any one of the upper arms constituting the bridge circuit and the lower arm in any one leg different from the leg to which the upper arm belongs. The failure according to claim 1, wherein a first failure determination command pattern including a combination of an on command for the switching element and an off command for the switching element other than the on-commanded switching element is generated. Detection device. The failure determination unit has at least two of the current detection values acquired by the current acquisition unit when each of the switching elements is operated based on each of the six failure determination command patterns. When the detected value of the current acquired by the current acquisition unit under the first failure determination command pattern is less than the first threshold value, two of the at least two first failure determination command patterns The failure detection device according to claim 2, wherein it is determined that an open failure related to the switching element that has been instructed to be turned on has occurred. The failure determination unit detects the current on the DC side of the bridge circuit acquired by the current acquisition unit when each switching element is operated based on each of the six failure determination command patterns. When the detected values of the two currents acquired by the current acquisition unit under the two first failure determination command patterns are larger than the second threshold value, the two first failure determination values are used. The failure detection device according to claim 2 or 3, wherein it is determined that a short-circuit failure related to the switching element that has been commanded off has occurred in the leg to which the switching element that has been commanded to be turned on in the command pattern belongs. The failure determination unit detects the current on the DC side of the bridge circuit acquired by the current acquisition unit when each switching element is operated based on each of the six failure determination command patterns. When the detected values of the three currents acquired by the current acquisition unit under the three first failure determination command patterns are larger than the second threshold value, the three first failure determination values are used. Any one of claims 2 to 4 for determining that a short failure related to the switching element that has been commanded off has occurred in the leg to which the switching element that has been commanded on in two of the command patterns belongs. The failure detection device described in the section. The failure determination unit has the current on the DC side of the bridge circuit acquired by the current acquisition unit when each of the switching elements is operated based on each of the six failure determination command patterns. When the detected values of the four currents acquired by the current acquisition unit under the four first failure determination command patterns among the detected values are larger than the second threshold value, the four first failure determinations are made. It is determined that a short failure related to the switching element that has been commanded off has occurred in each of the legs to which each of the two switching elements that have been commanded on in two of the command patterns belongs. Switching that was on-commanded in two first failure judgment command patterns having a combination different from the combination of the two first failure judgment command patterns used when it was determined that a short failure has occurred. The failure detection device according to any one of claims 2 to 5, which determines that a short-circuit failure related to a switching element that has been ordered to be turned off may have occurred in the leg to which the element belongs. The failure determination unit detects the current on the DC side of the bridge circuit acquired by the current acquisition unit when each of the switching elements is operated based on each of the six first failure determination command patterns. If all of the values are greater than the second threshold, the short fault associated with the switching element is for all of the switching elements in the upper arm of the bridge circuit or all of the switching elements in the lower arm of the bridge circuit. The failure detection device according to any one of claims 2 to 6, which is determined to have occurred. The bridge circuit is a single-phase bridge circuit.
As each of the four command patterns, the command generation unit gives an on command to the switching element of any one upper arm and the switching element of any one lower arm constituting the bridge circuit, and the on command. The failure detection device according to claim 1, which generates a first failure determination command pattern including a combination of an off command for the switching element other than the commanded switching element. The failure determination unit has two or more of the current detection values acquired by the current acquisition unit when each of the switching elements is operated based on each of the four failure determination command patterns. If the detected values of the two or three currents acquired by the current acquisition unit under the three first failure determination command patterns are less than the first threshold value, the two or three firsts. It is determined that an open failure related to the switching element that was on-commanded in two of the failure determination command patterns of the above has occurred, and the current is acquired under the four first failure determination command patterns. When the detected values of the four currents acquired by the unit are less than the first threshold value, it is determined that an open failure related to at least two of the four switching elements has occurred. The failure detection device according to claim 8. The failure determination unit detects the current on the DC side of the bridge circuit acquired by the current acquisition unit when each switching element is operated based on each of the two first failure determination command patterns. Among the values, when the detected value of the current acquired by the current acquisition unit under one of the first failure determination command patterns is larger than the second threshold value, the one first failure determination command pattern is used. 8. It is determined that a short failure related to one of the two switching elements to which the on command has been commanded has occurred in the leg to which each of the switching elements to which the on command has been commanded belongs. 9. The failure detection device according to 9. The failure determination unit detects the current on the DC side of the bridge circuit acquired by the current acquisition unit when each switching element is operated based on each of the two first failure determination command patterns. If all of the values are greater than the second threshold, the short fault associated with the switching element is for all of the switching elements in the upper arm of the bridge circuit or all of the switching elements in the lower arm of the bridge circuit. The failure detection device according to any one of claims 8 to 10, wherein it is determined that the current has occurred. A voltage acquisition unit that acquires a detected value of the voltage on the DC side of the power converter, and
A current that calculates an estimated value of the current flowing through each of the switching elements based on the detected value of the voltage acquired by the voltage acquisition unit, the time when the switching element is commanded to be turned on, and the impedance of the load circuit. Estimator and
Equipped with
The failure determination unit is at least one of the differences or ratios between each of the detected values of the current acquired by the current acquisition unit and each of the estimated values of the current calculated by the corresponding current estimation unit. The failure detection device according to any one of claims 1 to 11, wherein when the difference or ratio is out of the predetermined range, it is determined that a failure has occurred in the current detection unit provided in the power conversion device. .. The bridge circuit is a three-phase bridge circuit.
As each of the command patterns of 6, the command generation unit is in a leg different from the switching element of any one of the upper or lower arms constituting the bridge circuit and the leg to which the arm belongs. Generates a second failure determination command pattern consisting of a combination of an on command for the switching element of an arm on a side different from the arm and an off command for the switching element other than the on-commanded switching element. death,
The failure detection device according to any one of claims 1 to 7, wherein the failure determination unit determines a failure of an overcurrent detection unit provided corresponding to each of the switching elements in the power conversion device. When an overcurrent has flowed through the switching element ordered on under the second failure determination command pattern, the failure determination unit is on-commanded under the second failure determination command pattern. The failure detection device according to claim 13, wherein the overcurrent detection unit corresponding to the switching element for which it is determined that an overcurrent has flowed among the switching elements has been determined to be normal. A power conversion device that generates power used to drive a motor by converting DC to AC power or AC to DC power by turning on and off multiple switching elements that make up a bridge circuit.
The failure detection device according to any one of claims 1 to 14, which detects a failure of the power conversion device, and the failure detection device.
A motor drive device.

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