JP7545288B2 - Abnormality determination device and method for determining abnormality of pump drive device, and abnormality determination device during motor startup - Google Patents

Description

This disclosure relates to technology for determining abnormalities in pump drive devices and motors.

Multi-phase, for example three-phase, brushless motors are widely used in various industrial fields. For example, in fuel cell systems, they are used as the drive source for fuel cell cooling pumps, hydrogen pumps, etc. In such systems using brushless motors, if an abnormality occurs such as the motor not starting or the desired rotation speed not being obtained, it can cause problems in the operation of the entire system, so various methods are adopted to detect abnormalities in the motor or the controller that drives it. For example, in Patent Document 1 below, the actual rotation speed of the motor is detected, and if the relationship between the target rotation speed instructed to the motor and the detected actual rotation speed does not fall within a predetermined range, it is determined that an abnormality has occurred in the pump drive device equipped with the motor and controller.

JP 2014-76781 A

However, due to this relationship between the target rotation speed and the actual rotation speed, a problem exists in that devices that detect abnormalities in a pump drive device cannot accurately detect pump abnormalities unless they accurately detect the actual rotation speed of the motor. In particular, so-called sensorless motor control devices that detect the rotation speed using the induced voltage of the motor's drive coil may be unable to detect the rotation speed or may misdetect the rotation speed under certain conditions, such as in the low rotation speed range, making it difficult to accurately determine an abnormality.

This disclosure can be realized in the following forms or application examples:

(1) As one aspect of the present disclosure, there is provided an abnormality determination device for a pump drive device driven by a motor. The abnormality determination device for the pump drive device includes a detection unit that determines an actual rotation speed of a motor that drives a pump in a sensorless manner, a control unit that controls operation of the motor by specifying a target rotation speed of the motor and performs synchronous control to rotate the motor by forming a rotating magnetic field when the motor is started , and a determination unit that performs abnormality determination processing to determine that an abnormality has occurred when an accumulated period during which a deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold. Thus, when the actual rotation speed can be detected, the determination unit performs the abnormality determination process, and when the deviation falls within a predetermined range, performs a reduction process to reduce the cumulative period to a value smaller than the threshold value . During at least a part of the period during which the synchronous control is performed and the detection unit cannot detect the actual rotation speed, the determination unit performs the abnormality determination process by treating the expected rotation speed in the synchronous control as the actual rotation speed, and suppresses the reduction process when the deviation falls within a predetermined range . In this way, even if there is a period during which the actual rotation speed of the motor cannot be detected due to control of the motor operation, and a rotation speed different from the actual rotation speed of the motor is detected during this period, the cumulative period is erroneously reduced significantly, and it is possible to suppress the occurrence of a situation in which it is not possible to detect an abnormality in the rotation of the motor. The period during which the actual rotation speed of the motor cannot be detected may occur when the rotation speed of the motor is low, for example, when the rotation speed of the motor is detected sensorlessly by an induced voltage generated in a non-energized coil of the motor. Of course, even if a sensor such as a Hall element is provided to detect the rotation speed, the present invention can be applied in the same way when the rotation speed cannot be detected. Here, abnormalities in the rotation of the motor include, in addition to a malfunction of the motor itself, a stuck malfunction of a member such as the impeller of the pump driven by the motor, and an abnormality in a drive circuit such as an inverter that drives the motor.
(2) In the abnormality determination device for a pump drive device, the cumulative period is
[1] A value obtained by accumulating a time during which the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value,
[2] A value obtained by accumulating the rotation speed difference when the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value,
[3] A cumulative amount of a shortage of a flow rate of the fluid supplied by the pump from a predetermined value when the deviation between the target rotation speed and the actual rotation speed is equal to or larger than a predetermined value,
In this way, it is possible to use various parameters to determine whether or not an abnormality has occurred, and therefore it is possible to flexibly determine whether or not an abnormality has occurred.
(3) In the abnormality determination device for a pump drive device, the control unit may perform synchronous control when the motor is started, and the detection unit may be unable to detect the actual rotation speed during at least a portion of the period during which the synchronous control is performed. When performing synchronous control, it is often difficult to accurately detect the actual rotation speed in the low rotation speed range. Even in this case, abnormality detection can be performed accurately.
(4) In the abnormality determination device for a pump drive device, the detection unit may detect an actual rotation speed of the motor from an induced voltage of a multi-phase coil of the motor. In this way, the rotation speed of the motor can be detected without a sensor. The multi-phase coil is not limited to a three-phase coil, and may be a five-phase coil, for example.
(5) In such an abnormality determination device for a pump drive device, the deviation between the target rotation speed and the actual rotation speed may be equal to or greater than a predetermined deviation. The deviation can be determined based on the difference in rotation speed, and the predetermined difference in rotation speed may be a fixed value or may be determined as a ratio to the target rotation speed, such as 1/10 of the target rotation speed. Of course, the difference in rotation speed from the target rotation speed may be set using a function, a graph, or the like.
(6) In the abnormality determination device for a pump drive device, the reduction process performed by the determination unit may be a process of initializing the cumulative period, and suppression of the reduction process during a period in which the actual rotation speed of the motor cannot be detected may be realized by prohibiting the initialization. The reduction process may be realized by gradually reducing (decrementing) the cumulative period, or may be realized by directly resetting the cumulative period to an initial value.
(7) As another aspect of the present disclosure, there is provided a method for determining an abnormality in a pump driven by a motor, which comprises: determining an actual rotation speed of the motor in a sensorless manner; specifying a target rotation speed of the motor to control the operation of the motor; and performing synchronous control to rotate the motor by forming a rotating magnetic field when the motor is started ; and , when the actual rotation speed can be detected, performing an abnormality determination process to determine that an abnormality exists when an accumulated period during which a deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold value; and performing a reduction process to reduce the accumulated period to a value smaller than the threshold value when the deviation falls within a predetermined range;
During at least a part of the period during which the synchronous control is performed and during a period during which the actual rotation speed cannot be detected, the expected rotation speed in the synchronous control is treated as the actual rotation speed and the abnormality determination process is performed, and the reduction process is suppressed when the deviation falls within a predetermined range . With this method, even if there is a period during which the actual rotation speed of the motor cannot be detected due to control of the operation of the motor, an abnormality in the pump can be accurately determined.

(8) As yet another aspect of the present disclosure, there is provided an abnormality determination device for determining an abnormality during startup of a motor, the abnormality determination device for a motor including: a detection unit that determines an actual rotation speed of the motor in a sensorless manner; a control unit that sequentially indicates a target rotation speed of the motor by synchronous control during startup of the motor and forms a rotating magnetic field to control startup of the motor; and a determination unit that performs an abnormality determination process to determine that an abnormality has occurred when a cumulative period during which a rotation speed difference between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold. Here, the determination unit performs the abnormality determination process when the actual rotation speed can be detected, and performs a reduction process to reduce the cumulative period to a value smaller than the threshold value when the rotation speed difference between the target rotation speed and the actual rotation speed falls within a predetermined range, and performs the abnormality determination process by treating the expected rotation speed in the synchronous control as the actual rotation speed during at least a portion of the period during which the synchronous control is performed and during a period during which the detection unit cannot detect the actual rotation speed, and suppresses the reduction process when the rotation speed difference falls within a predetermined range . In this way, even if there is a period during which the actual rotation speed of the motor cannot be detected due to control of the motor operation, it is possible to accurately determine an abnormality in the motor.

The present disclosure can be implemented in other ways. For example, it can be implemented by being incorporated into a pump control device or a pump control method. It can also be realized as a motor drive device or driver that drives a motor, or a drive method thereof, or as a control device that instructs such a driver to drive a pump or motor. When incorporated into a driver, the target rotation speed is provided from a higher-level control device, and when incorporated into a control device, the actual rotation speed is obtained from the driver side.

1 is a schematic configuration diagram showing an abnormality determination device for a pump drive device according to an embodiment; FIG. 2 is a configuration diagram showing an abnormality determination device for a pump drive device, focusing on a drive system of a motor. 4 is a flowchart showing an abnormality determination processing routine according to the first embodiment. FIG. 4 is an explanatory diagram showing a method for determining an abnormality. 5 is an explanatory diagram illustrating a comparison of abnormality determination methods in the first embodiment; FIG. 10 is a flowchart showing an abnormality determination process routine according to a second embodiment. 13 is a flowchart showing an abnormality determination process routine according to a third embodiment.

A. First embodiment:
(1) Hardware configuration:
The configuration of a fuel cell system including a pump drive device abnormality determination device 20 of the first embodiment is shown in Fig. 1. As shown in the figure, this pump drive device abnormality determination device 20 is a device that determines an abnormality in a drive device of a pump 41 for circulating cooling water provided in a coolant circulation system 40 that cools a fuel cell 30. First, the configuration for operating the fuel cell 30 will be described. The fuel cell 30 includes a well-known fuel gas supply and exhaust system and an oxidizing gas (atmosphere) supply and exhaust system (not shown), and generates electricity by an electrochemical reaction between hydrogen, which is a fuel gas, and oxygen contained in the atmosphere. The fuel cell 30 generates heat by the electrochemical reaction, and is cooled by the coolant circulation system 40. The fuel gas supply and exhaust system, which supplies and exhausts the fuel gas and the atmosphere, the oxidizing gas supply and exhaust system, and the coolant circulation system 40 are controlled by a control unit 70. The control unit 70 receives a signal FCS from a group of sensors, such as a temperature sensor and a pressure sensor (not shown), provided in the fuel cell 30, and outputs a signal ACS to a group of actuators, such as injectors and various solenoid valves, provided in the fuel cell 30, to operate the fuel cell 30 in a desired state. Since the configuration and operation method of the fuel cell 30 are well known, details other than those of the coolant circulation system 40 will not be shown or described.

The coolant circulation system 40 is composed of a pump 41, a radiator 43 that exchanges heat between the coolant circulated by the pump 41 and the atmosphere, a three-way valve 45 that branches the coolant discharged from the fuel cell 30 to either the radiator 43 or a bypass line 46, and piping 47 that forms a circulation path that circulates the coolant between the fuel cell 30 and the radiator 43. The pump 41 is also provided with a pump drive device 50 consisting of a drive motor 51 and a driver 60.

The motor 51 of the pump drive device 50 is driven by a driver 60 using power from a battery 52, which is a DC power source. The driver 60 is connected to a control unit 70, and operates the motor 51 at a target rotation speed St* instructed by the control unit 70. The driver 60 outputs the actual rotation speed Srr of the motor 51 to the control unit 70. The control unit 70 uses the target rotation speed St* and the actual rotation speed Srr to determine whether there is an abnormality in the pump driven by the motor 51.

Details of the abnormality determination device 20 for the pump drive device 50, including the drive system for the motor 51, are shown in Figure 2. As shown in the figure, the abnormality determination device 20 for the pump drive device 50 is composed of the motor 51, a driver 60, and a control unit 70. The driver 60 is composed of an inverter 62 and a drive circuit 64. The drive circuit 64 of the driver 60 receives an instruction for the target rotation speed St* from the control unit 70, and controls the switching element provided in the inverter 62 to drive the motor 51. Below, the circuit configuration for driving the motor 51 and the function of each part will be explained in order.

In this embodiment, the motor 51 that drives the pump 41 is a brushless three-phase PM motor. The motor 51 generates a rotating magnetic field by passing sinusoidal currents with a phase difference of 120 degrees through the three-phase coils of U, V, and W phases, which rotates the rotor 53 equipped with a permanent magnet. When the rotor 53 rotates, the impeller (not shown) of the pump 41 rotates, pushing the cooling liquid in the pipe 47 toward the fuel cell 30. In this embodiment, the three-phase coils of U, V, and W phases are star-connected, and one end of each coil is connected to the output from the inverter 62.

The inverter 62 comprises three sets of switching elements S1-S2, S3-S4, and S5-S6 arranged in parallel between the power supply lines from the battery 52, and protective diodes D1-D6 connected between the collectors and emitters of the switching elements S1-S6. Drive signals Du+, Du-, Dv+, Dv-, Dw+, and Dw- are input from the drive circuit 64 to the gates of each of the switching elements S1-S6. The switching elements are driven by these drive signals and sequentially enter a conductive state (turned on). Note that the switching elements of each set are never in a conductive state at the same time.

The connection point of each group of switching elements S1-S2, S3-S4, and S5-S6 is connected to one end of the three-phase coils of the U-phase, V-phase, and W-phase of the motor 51. Therefore, for example, when the drive signal Du+ becomes active and the switching element S1 becomes conductive, and the drive signal Dv- becomes active and the switching element S4 becomes conductive, the current from the battery 52 flows from the switching element S1 through the U-phase coil and the V-phase coil, and further through the switching element S4. The current Iu flowing through the U-phase coil can be detected by the current sensor 55u provided on the line connected to the U-phase coil. Similarly, a current sensor 55V is provided on the line connected to the V-phase coil, and a current sensor 55w is provided on the line connected to the W-phase coil, respectively, to detect the current Iv flowing through the V-phase coil and the current Iw flowing through the W-phase coil.

The drive circuit 64 includes a motor control unit 65, an output unit 66, a detection unit 67, and an input/output unit 68. The detection unit 67 reads signals from the current sensors 55u, 55v, 55w to detect the phase currents Iu, Iv, Iw of the motor 51. For ease of understanding, it is assumed here that all currents flowing through the three-phase coils are detected, but since the currents flowing into and out of each phase coil of the motor 51 correspond to each other, it is not necessary to provide current sensors for all three phases.

The input/output unit 68 receives instructions from the motor control unit 65 and outputs signals Du+, Du-, Dv+, Dv-, Dw+, and Dw- that drive the switching elements S1 to S6 of the inverter 62. The motor control unit 65 controls the rotation speed of the motor 51 toward the target rotation speed St* received via the input/output unit 68. At that time, the motor control unit 65 calculates the phase currents required to increase or decrease the rotation speed and outputs them to the output unit 66. In response to this instruction, the output unit 66 determines the on-time of the signals Du+, Du-, Dv+, Dv-, Dw+, and Dw- that drive the switching elements S1 to S6 of the inverter 62 and outputs them. The output unit 66 functions as a pulse width modulation module (PWM) that controls the on-time of each switching element.

The motor control unit 65 detects the change in current of each phase coil through the detection unit 67. In the coils other than the coils through which the two sets of switching elements are turned on and the drive current flows, an induced voltage is generated according to the positional relationship with the permanent magnets provided on the rotor 53. The current corresponding to this induced voltage can be detected by a current sensor. If the motor 51 rotates at a certain rotation speed or more, the current change due to the induced voltage is large enough to calculate the angle of the rotor 53, so the motor control unit 65 calculates the rotation phase of the rotor 53, that is, the angle with respect to the three-phase coils u, v, and w, and calculates the magnitude of the current to be passed through each phase coil based on this angle, and controls the on/off of each switching element S1-S6 of the inverter 62 through the output unit 66. The motor control unit 65 calculates the actual rotation speed Srr of the motor 51 from the change in the rotation angle of the rotor 53, and outputs it to the control unit 70 through the input/output unit 68.

On the other hand, when the rotation speed of the motor 51 is low, for example when the motor 51 that has been stopped is started by an instruction from the control unit 70, the rotation angle of the rotor 53 cannot be detected by the current change due to the induced voltage. Moreover, when the rotor 53 is stopped, it is not possible to detect the angle at which the rotor 53 is stopped relative to each phase coil, and therefore it is not possible to identify the coil that should be energized first. Therefore, in such a case,
[1] A detection process for detecting the rotation angle of the stopped rotor 53 before the formation of a rotating magnetic field;
[2] Synchronous control to form a rotating magnetic field without detecting the rotation angle of the rotor 53;
In this embodiment, the method [2] is adopted.

In synchronous control, current is passed through each phase coil u, v, w without detecting the position of the rotor 53, forming a slowly rotating rotating magnetic field. In this case, since the rotation angle of the rotor 53 is not detected, it is often not possible to form a rotating magnetic field at a highly efficient angle with respect to the direction of the magnetic flux formed by the permanent magnet of the rotor 53. However, the rotor 53 gradually begins to rotate and synchronizes with the rotation of the rotating magnetic field over time. During this time, the induced voltage is not large enough, so the motor control unit 65 cannot detect the rotation angle of the rotor 53 from the induced voltage, and therefore the rotation speed. For this reason, the motor control unit 65 assumes that the rotor 53 is rotating at a rotation speed corresponding to the rotation speed of the rotating magnetic field that it itself specifies, and outputs the rotation speed corresponding to the rotation speed of the rotating magnetic field as the actual rotation speed Srr to the outside, here to the control unit 70.

The control unit 70 incorporates a computer (CPU), memory, an input/output interface unit, etc., and executes a program described later to realize functions such as an instruction unit, a judgment unit, and an output unit. As shown in FIG. 2, the control unit 70 outputs the target rotation speed St* to the drive circuit 64 of the inverter 62 through the function of the instruction unit, receives the actual rotation speed Srr from the drive circuit 64, judges an abnormality of the pump 41 through the function of the judgment unit, and outputs the result of the abnormality judgment to the outside, for example, to a warning light on the instrument panel or a diagnosis computer, etc., through the function of the output unit. The detected abnormality of the pump 41 includes, in addition to a failure of the motor 51 itself that drives the pump 41, a stuck failure of a member such as the impeller of the pump 41 driven by the motor 51, an abnormality of the drive circuit such as the inverter 62 that drives the motor 51, and further an abnormality on the control side that controls the inverter, and an abnormality such as a broken wire or a short circuit failure of various wiring. In FIG. 2, the signal Ssc output from the input/output unit 68 of the drive circuit 64 to the control unit 70 is a signal that becomes active when the drive circuit 64 is performing synchronous control, but in the first embodiment, the drive circuit 64 does not have the function of outputting this signal. This signal Ssc will be described in the second embodiment.

(2) Abnormality Judgment Process:
The abnormality determination process performed by the abnormality determination device 20 of the pump drive device 50 will be described with reference to the flowchart of FIG. 3. The abnormality determination process shown in the figure is repeatedly executed at a predetermined interval by a CPU built into the control unit 70. When this process is started, it is first determined whether to operate the motor 51 (step S105). If it is not necessary to operate the motor 51, nothing is done, and the process goes to "NEXT" and ends this processing routine. The case where operation is not necessary corresponds not only to the case where it is not necessary to operate the pump 41 to circulate the cooling liquid, but also to the case where the motor 51 has failed to start and is waiting for the next restart, etc.

If it is determined that the motor 51 should be operated, the control unit 70 then instructs the driver 60 on the target rotation speed St* of 51 (step S110) and receives the actual rotation speed Srr of the motor 51 from the driver 60 (step S120). The control unit 70 then determines whether the absolute value of the deviation between the instructed target rotation speed St* and the acquired actual rotation speed Srr (|St*-Srr|) is greater than a predetermined rotation speed threshold value ΔS (step S125). This processing corresponds to the case where the target rotation speed St* and the actual rotation speed Srr are separated.

The driver 60 receives the target rotation speed St* and starts the motor 51, but the rotation speed of the motor 51 gradually increases toward the target rotation speed St*, and during that time the actual rotation speed Srr is below the target rotation speed St*. Moreover, as described above, at the time of startup, synchronous control is performed, so the increase in the rotation speed is gradual, and during this time the driver 60 cannot detect the rotation speed of the rotor 53 due to the induced voltage, so instead of the actually measured rotation speed, it outputs the expected rotation speed for control as the actual rotation speed Srr.

This is illustrated in Figure 4. In the figure, the solid line J1 shows the case where synchronous control causes the actual rotation speed Srr of the rotor 53 of the motor 51 to rise toward the target rotation speed St*. On the other hand, the dashed line B1 shows the case where some abnormality occurs and the actual rotation speed Srr of the rotor 53 does not rise to the target rotation speed St*. When synchronous control is being performed, the drive circuit 64 of the driver 60 does not actually measure the actual rotation speed Srr, so even if an abnormality occurs, the actual rotation speed Srr will not rise as shown by the dashed line B1, but will rise as shown by the solid line J1.

As a result, the deviation between the actual rotation speed Srr and the target rotation speed St* output during the synchronous control exceeds the rotation speed threshold value ΔS until time t1. In this case, the control unit 70 increments the abnormality determination counter Cerr (step S140). In other words, the abnormality determination counter Cerr is equivalent to determining the cumulative period when the deviation between the actual rotation speed Srr and the target rotation speed St* is greater than a predetermined value. On the other hand, at time t1, the apparent deviation becomes smaller than the rotation speed threshold value ΔS (step S125: "NO"), so next, a determination is made as to whether the time t is smaller than a predetermined timing ts after the implementation period of the synchronous control (step S135). If t<ts, that is, the timing ts after the implementation period of the synchronous control has not yet been reached, nothing is done. If the time t is after the predetermined timing ts (step S135: "NO"), a process is performed to initialize the abnormality determination counter Cerr to a value of 0 (step S150). Here, initialization corresponds to a reduction process that reduces the cumulative period that accumulates the time during which the deviation between the actual rotation speed Srr and the target rotation speed St* is large. If initialization is performed, the abnormality determination counter Cerr, which is the cumulative period, is immediately reduced to a value of 0. Initialization includes a method in which initialization is not performed all at once, for example, by dividing it into two stages. Also, not performing initialization based on the judgment in step S135 corresponds to suppressing (here, prohibiting) initialization, including the reduction of the cumulative period.

After performing any of these processes, it is determined whether the abnormality determination counter Cerr is greater than the threshold value ThC (step S165). If the abnormality determination counter Cerr is greater than the threshold value ThC, it is determined that an abnormality has occurred, and this is output as an abnormality signal Serr (step S170). If the abnormality determination counter Cerr is not greater than the threshold value ThC, it is determined that no abnormality has occurred, and the process does not proceed, but goes to "NEXT" and ends this processing routine for the time being.

The above-mentioned abnormality determination processing routine is repeatedly executed at a predetermined interval, so if the actual rotation speed Srr of the rotor 53 of the motor 51 never reaches the target rotation speed St* as shown by the dashed line B1, the determination in step S125 is repeatedly "YES", and the abnormality determination counter Cerr is incremented each time this determination processing routine is executed (step S140). As a result, the abnormality determination counter Cerr continues to count up as shown by the dashed line Eb1, and exceeds the threshold value ThC at time t2, so an abnormality is determined. On the other hand, if the actual rotation speed Srr of the rotor 53 increases normally as a result of the synchronous control, at a predetermined timing ts after the implementation period of the synchronous control, the abnormality determination counter Cerr is initialized to a value of 0 (step S150), so no abnormality is determined.

In FIG. 4, the dashed line B1 is a virtual rotation speed, and if there is some abnormality, for example, if the impeller of the pump 41 is caught in a foreign object and cannot rotate, or if any of the three-phase coils u, v, and w is broken and cannot rotate normally, the rotor 53 of the motor 51 will not rotate normally due to synchronous control, but even in that case, the drive circuit 64 will continue to output the actual rotation speed Srr as in the solid line J1 during the implementation period of synchronous control, assuming that the drive circuit 64 is rotating normally. If the actual rotation speed Srr has increased to a rotation speed that is smaller than the target rotation speed St* by the rotation speed threshold value ΔS, the rotation speed can be detected by the induced voltage, and the rotation speed of the rotor 53 is detected as the inverse of the period of the induced voltage, and this is output as the actual rotation speed Srr. In other words, if the start of the motor 51 by synchronous control fails, the actual rotation speed Srr will deviate from the normal value at the timing tp when the synchronous control ends, as shown by the dashed line D1 in FIG. 4. Deviation from the normal value means that if the rotor 53 cannot rotate due to jamming or the like, the actual rotation speed St* will be 0, and if the three-phase coil is partially disconnected, the actual rotation speed Srr may not be 0, but may be lower than the target rotation speed St* by exceeding the rotation speed threshold. If the rotation speed is so small that it cannot be detected by induced voltage, it will be considered to be 0 even if the rotor is rotating.

The manner in which an abnormality is detected in the abnormality determination processing routine when the motor 51 cannot be started normally by such synchronous control will be described with reference to FIG. 5. FIG. 5 shows a case in which the motor 51 does not start even when synchronous control is performed. When the control unit 70 instructs the driver 60 to start the motor 51 and instructs the target rotation speed St*, during the period Psc in which synchronous control is performed, as shown by the solid line J2, the drive circuit 64 of the driver 60 continues to output a virtual rotation speed under synchronous control that increases toward the target rotation speed St* as the actual rotation speed Srr. During this time, the abnormality determination counter Cerr is sequentially incremented and increased.

This situation is shown in two ways in FIG. 5 as (1) and (2). The abnormality determination counter Cerr in (1) shows a case where the series of processes in the process routine in FIG. 3, that is, the judgment in step S135, that is, the judgment of whether the time t is the timing ts when the synchronous control implementation period Psc has been exceeded, is not performed until the time t exceeds the timing ts, and the process of initializing the abnormality determination counter Cerr (step S150) is not performed. In this case, as shown by the dashed line Ej2 in FIG. 5, the abnormality determination counter Cerr is initialized to a value of 0 at the timing t1 when the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr becomes smaller than the rotation speed threshold value ΔS. Therefore, even if the implementation period Psc of the synchronous control has elapsed and the start of the motor 51 has failed, the abnormality determination counter Cerr is initialized, so when the start is attempted again and synchronous control is performed, the same process is repeated, and no matter how many times synchronous control is performed and start fails, this cannot be detected as an abnormality.

In contrast, in this embodiment, even if the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr becomes smaller than the rotation speed threshold value ΔS (step S125: NO), the process of initializing the abnormality determination counter Cerr (step S150) is not performed until the time t exceeds the timing ts (step S135: YES). Therefore, as shown by the solid line Eb2 in FIG. 5 (2), the abnormality determination counter Cerr is not initialized at timing t1 and is maintained at the incremented value. When the synchronous control ends, the determination in step S105 is "NO" until the start of the next synchronous control, and no change occurs in the abnormality determination counter Cerr. Next, when the synchronous control is started to start the motor 51 (timing t3 in the figure), the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr is larger than the rotation speed threshold value ΔS, so the determination in step S125 is again "YES" and the abnormality determination counter Cerr is incremented. As a result, the abnormality determination counter Cerr eventually exceeds the threshold value ThC (timing t4 in the figure), and the control unit 70 detects an abnormality as the motor 51 cannot start the pump 41, and outputs this (steps S165, S170). If the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr becomes smaller than the rotation speed threshold value ΔS before the abnormality determination counter Cerr reaches the threshold value ThC, the abnormality determination counter Cerr is initialized, no abnormality is determined, and the pump 41 is determined to have started normally.

In the first embodiment described above, the driver 60, which detects the rotation speed without a sensor and drives the motor 51, performs synchronous control when the motor 51 is started, and even if the actual rotation speed of the rotor 53 is not actually detected but the controlled rotation speed is output as the actual rotation speed Srr of the motor 51 during the period of implementation of the synchronous control, an abnormality is not erroneously determined. If the motor 51 cannot be started even after repeated synchronous control, a retry to start the motor 51 again is permitted, and if the rotation speed cannot be detected by the induced voltage even after a preset number of retries, an abnormality in the pump 41 can be determined. In addition, after the motor 51 is started once and the actual rotation speed Srr of the motor 51 can be detected by the induced voltage, if the deviation between the target rotation speed St* and the actual rotation speed Srr continues to be equal to or greater than the rotation speed threshold value for some reason, the abnormality determination counter Cerr is incremented (FIG. 3, step S140), so the occurrence of an abnormality can be determined even without synchronous control.

In the first embodiment described above, in step S135, it is determined whether the time t has exceeded a predetermined time ts, but this time ts may be defined as a predetermined period from the timing when synchronous control is started. Also, when the motor 51 is repeatedly started, the start of synchronous control may be defined as the timing of the end of a period of waiting for resynchronization when synchronous control is performed again.

B. Second embodiment:
Next, a second embodiment will be described. The abnormality determination device 20 for a pump drive device of the second embodiment has the same hardware configuration as the first embodiment, but differs from the first embodiment in that the control unit 70 can use the signal Ssc output by the drive circuit 64 among the configurations shown in Fig. 1. This signal Ssc is a signal indicating that the drive circuit 64 is performing synchronous control.

Figure 6 is a flowchart showing the abnormality determination processing routine in the second embodiment. This processing routine differs only in that step S137 is performed instead of step S135 in the first embodiment. That is, in the second embodiment, instead of determining whether time t, which is the elapsed time from the start of synchronous control, is greater than timing ts that exceeds the implementation period of synchronous control in advance (Figure 3: step S135), whether synchronous control is being performed is determined based on whether signal Ssc is on or not (step S137). As a result, while synchronous control is being performed (Ssc is on), even if the absolute value of the deviation between target rotation speed St* and actual rotation speed Srr is smaller than rotation speed threshold value ΔS, the process of initializing abnormality determination counter Cerr (step S150) is not performed. Therefore, the second embodiment can also achieve the same effects as the first embodiment.

C. Third embodiment:
Next, a third embodiment will be described with reference to FIG. 7. In the third embodiment, the same hardware configuration as in the first and second embodiments is used, but as shown in FIG. 7, the process corresponding to step S135 in the first embodiment and step S137 in the second embodiment is not performed. In other words, if it is a synchronous control period, the determination not to initialize the abnormality determination counter Cerr is not executed. In the third embodiment, as shown in the figure, instead of determining whether it is a synchronous control period or not, if the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr is greater than the rotation speed threshold value ΔS (step S125, "YES"), the abnormality determination counter Cerr is incremented by one (step S142). On the other hand, when the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr becomes equal to or less than the rotation speed threshold value ΔS (step S125: NO), the abnormality determination counter Cerr is decremented by a value of 4 (step S152), and when the abnormality determination counter Cerr becomes less than 0 (step S154), it is initialized to a value of 0 (step S155).

In the third embodiment in which such processing is performed, in accordance with the example shown in FIG. 4, the abnormality determination counter Cerr is incremented with a slope of 1 until time t1, but when the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr becomes smaller than the rotation speed threshold value ΔS during synchronous control, the abnormality determination counter Cerr is decremented and the value decreases. After that, when the implementation period of synchronous control ends, if the start of the motor 51 is successful, the abnormality determination counter Cerr continues to be decremented and is initialized to a value of 0. If the start of the motor 51 fails, the abnormality determination counter Cerr is decremented for the remaining time of synchronous control (time t1 to ts), but if the detection of the rotation speed by the induced voltage fails, the decrement of the abnormality determination counter Cerr stops, and when the start of the motor 51 by synchronous control starts again, the abnormality determination counter Cerr is incremented again. As a result, if the motor 51 does not start even after several synchronization controls, the abnormality determination counter Cerr will eventually exceed the threshold value ThC, and an abnormality in the pump 41 can be detected. If the motor 51 can rotate normally during the retry, the abnormality determination counter Cerr is decremented by 4 and eventually initialized to 0. In this embodiment, the decrement is performed with a larger value than the increment, in order to quickly initialize the abnormality determination counter Cerr when the absolute value of the deviation between the target rotation speed St* and the actual rotation speed Srr of the motor 51 becomes smaller than the rotation speed threshold value ΔS, that is, when the motor 51 starts normally. Of course, the increment and decrement speeds may be the same, or the increment may be performed with a larger value.

D. Other embodiments:
In each of the above embodiments, the cumulative period is calculated by using a counter to accumulate the time during which the deviation between the target rotation speed and the actual rotation speed of the motor 51 is equal to or greater than a predetermined value. However, the cumulative period may be calculated, for example, as an accumulated value of the rotation speed difference when the deviation between the target rotation speed and the actual rotation speed of the motor 51 is equal to or greater than a predetermined value. In this case, when the rotation speed difference is large, the cumulative period becomes large in a short time, so that the larger the rotation speed difference, the shorter the time required to determine whether an abnormality exists. The cumulative period may be calculated as an accumulated amount of the shortage of the flow rate of the refrigerant from a predetermined flow rate by the pump 41 when the deviation between the target rotation speed and the actual rotation speed of the motor 51 is equal to or greater than a predetermined value. In this case, a flow meter that detects the flow rate of the refrigerant, which is a fluid, is provided in the pipe 47, and the shortage of this flow rate from a predetermined rated flow rate is accumulated by the control unit 70. In this case, the larger the shortage of flow rate, the larger the cumulative period becomes in a short time, so that the larger the shortage of flow rate, the shorter the time required to determine whether an abnormality exists.

In the above embodiment, the pump 41 that circulates the coolant for the fuel cell 30 is the pump that is subject to abnormality judgment. Therefore, if an abnormality is judged in the pump, the operation of the fuel cell 30 is stopped, or the abnormality is displayed on the instrument panel to warn the driver, and other measures are taken, so that the fuel cell 30 can be prevented from being operated without being sufficiently cooled. The pump is not limited to the fuel cell 30, and may be applied to other coolant circulation pumps, such as a coolant circulation pump that cools the motor of an electric vehicle. Of course, the abnormality judgment device can be implemented not only for coolant circulation pumps, but also for air supply pumps (compressors) in fuel cells and hydrogen pumps. Furthermore, it may be applied to various on-board pumps, various pumps for pumping and draining water, and the like.

Furthermore, the present invention may be implemented as an abnormality determination device for a motor that drives an object other than a pump. The motor is not limited to one that performs synchronous control at start-up, and may be applied to a sensorless motor that detects the stop position of the stator and then forms a rotating magnetic field. Alternatively, the present invention may be applied to a configuration that detects the rotation speed using a sensor such as a Hall element, if there is a region where the rotation speed cannot be detected.

In each of the above embodiments, a part of the configuration realized by hardware may be replaced by software. At least a part of the configuration realized by software may be realized by a discrete circuit configuration. In addition, when a part or all of the functions of the present disclosure are realized by software, the software (computer program) may be provided in a form stored in a computer-readable recording medium. "Computer-readable recording medium" is not limited to portable recording media such as floppy disks and CD-ROMs, but also includes internal storage devices within a computer such as various RAMs and ROMs, and external storage devices fixed to a computer such as hard disks. In other words, "computer-readable recording medium" has a broad meaning including any recording medium to which data packets can be fixed, not temporarily.

The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in each form described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

20... Abnormality determination device for pump drive device, 30... Fuel cell, 40... Coolant circulation system, 41... Pump, 43... Radiator, 45... Three-way valve, 46... Bypass line, 50... Pump drive device, 51... Motor, 52... Battery, 53... Rotor, 55V, 55u, 55w... Current sensor, 60... Driver, 62... Inverter, 64... Drive circuit, 65... Motor control unit, 66... Output unit, 67... Detection unit, 68... Input/output unit, 70... Control unit

Claims (7)

An abnormality determination device for a pump drive device,
a detection unit that detects the actual rotation speed of the motor that drives the pump without using a sensor;
a control unit that controls the operation of the motor by specifying a target rotation speed of the motor , and performs synchronization control to rotate the motor by forming a rotating magnetic field when the motor is started ;
a determination unit that performs an abnormality determination process to determine that an abnormality has occurred when an accumulated period during which the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold;
Equipped with
The determination unit is
When the actual rotation speed can be detected, the abnormality determination process is performed, and when the deviation falls within a predetermined range, a reduction process is performed to reduce the cumulative period to a value smaller than the threshold value.
During at least a part of a period during which the synchronous control is performed and during a period during which the detection unit cannot detect the actual rotation speed, the expected rotation speed in the synchronous control is treated as the actual rotation speed to perform the abnormality determination process, and the reduction process is suppressed when the deviation falls within a predetermined range.
An abnormality determination device for a pump drive device. The accumulation period is:
[1] A value obtained by accumulating a time during which the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value,
[2] A value obtained by accumulating the rotation speed difference when the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value,
[3] A cumulative amount of a shortage of a flow rate of the fluid supplied by the pump from a predetermined value when the deviation between the target rotation speed and the actual rotation speed is equal to or larger than a predetermined value,
2. The abnormality determination device for a pump drive device according to claim 1, wherein the abnormality determination device is configured to determine whether or not the pump drive device is abnormal. 3. The abnormality determination device for a pump drive device according to claim 1, wherein the detection unit detects an actual rotation speed of the motor from an induced voltage in a multi-phase coil of the motor. 4. The abnormality determination device for a pump drive device according to claim 1, wherein the deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined rotation speed difference. the reduction process performed by the determination unit is a process of initializing the accumulation period,
The suppression of the reduction process during a period in which the actual rotation speed of the motor cannot be detected is realized by prohibiting the initialization.
The abnormality determination device for a pump drive device according to any one of claims 1 to 4 . A method for determining an abnormality in a pump drive device, comprising:
The actual rotation speed of the motor that drives the pump is calculated without a sensor.
A target rotation speed of the motor is specified to control the operation of the motor, and a synchronous control is performed to rotate the motor by forming a rotating magnetic field when the motor is started .
When the actual rotation speed can be detected, an abnormality determination process is performed in which an abnormality is determined to exist when an accumulated period during which a deviation between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold value, and when the deviation falls within a predetermined range, a reduction process is performed in which the accumulated period is reduced to a value smaller than the threshold value.
During at least a part of the period during which the synchronous control is performed and during a period during which the actual rotation speed cannot be detected , the expected rotation speed in the synchronous control is treated as the actual rotation speed to perform the abnormality determination process, and the reduction process is suppressed when the deviation falls within a predetermined range .
A method for determining an abnormality in a pump drive device. An abnormality determination device for determining an abnormality during startup of a motor, comprising:
A detection unit that detects an actual rotation speed of the motor without a sensor;
a control unit that sequentially indicates a target rotation speed of the motor by synchronous control when the motor is started, and forms a rotating magnetic field to control the start of the motor;
a determination unit that performs an abnormality determination process to determine that an abnormality has occurred when an accumulated period during which a rotation speed difference between the target rotation speed and the actual rotation speed is equal to or greater than a predetermined value exceeds a predetermined threshold value;
Equipped with
The determination unit is
When the actual rotation speed can be detected, the abnormality determination process is performed, and when a rotation speed difference between the target rotation speed and the actual rotation speed falls within a predetermined range, a reduction process is performed to reduce the cumulative period to a value smaller than the threshold value.
An abnormality determination device during motor startup, which, during at least a portion of the period during which the synchronous control is performed and during a period during which the detection unit cannot detect the actual rotation speed , performs the abnormality determination process by treating the estimated rotation speed in the synchronous control as the actual rotation speed, and suppresses the reduction process when the rotation speed difference falls within a predetermined range .

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