JP6208024B2 - Power converter and control method of power converter - Google Patents

Description

  Embodiments described herein relate generally to a power conversion device and a method for controlling the power conversion device.

  Conventionally, for railway vehicles, an auxiliary power supply for railway vehicles (hereinafter referred to as power conversion) that converts DC power from an overhead wire into DC power of a predetermined voltage and supplies it to in-vehicle equipment (air-conditioning / heating device, door opening / closing device, display device, etc.). Device). In this power converter, direct current power from an overhead wire is converted into alternating current power, insulated through a commercial frequency transformer, and then rectified to output direct current power to a load.

JP-A-6-327261

By the way, in the conventional power converter, the output current detector which monitors the output current of a power converter is provided, and when the abnormality, such as an overcurrent, occurs due to a load short circuit or the like, the power converter is protected. The one configured in this way has also been proposed.
However, when the output current detector fails, it is impossible to detect an abnormality, and there is a possibility that the power conversion device cannot be protected.

In order to solve the above-described problem, the boost chopper of the power conversion device of the embodiment boosts DC power supplied from an overhead wire to a predetermined voltage value and outputs the boosted voltage to the inverter.
The inverter converts DC power output from the boost chopper into AC power and outputs the AC power to the transformer.
The transformer boosts AC power output from the inverter and outputs it to the rectifier.
The rectifying unit rectifies the AC power output from the transformer and outputs the rectified power to the load.
On the other hand, the first current detection unit detects the input current of the boost chopper and outputs a first detection signal to the abnormality detection unit, and the second current detection unit detects the output current of the rectification unit and abnormally detects the second detection signal. Output to the detector.

As a result, when the first detection signal is in the current detection state and the second detection signal is in the current non-detection state based on the first detection signal and the second detection signal , the second current detection unit is abnormal . it detected.

FIG. 1 is a schematic configuration block diagram of a power conversion device for a railway vehicle according to the first embodiment. FIG. 2 is an explanatory diagram when the abnormality detection unit according to the first embodiment for detecting an abnormality in the second current detection unit is configured as a logic circuit. FIG. 3 is a schematic configuration block diagram of a power conversion device for a railway vehicle according to the second embodiment. FIG. 4 is an explanatory diagram when the abnormality detection unit in the second embodiment for detecting an abnormality in the second current detection unit is configured as a logic circuit.

Hereinafter, the power converter of an embodiment is explained in detail with reference to drawings.
The power conversion device according to the embodiment includes, for example, a railcar auxiliary power supply that converts DC power from an overhead wire into DC power of a predetermined voltage and supplies it to in-vehicle equipment (such as a cooling / heating device, a door opening / closing device, a display device) as a load. Used as a device.

[1] First Embodiment FIG. 1 is a block diagram showing a schematic configuration of a power converter for a railway vehicle according to a first embodiment.
The power converter 10 has an open contactor (breaker) in a current path between a pantograph 12 to which DC power is supplied from a DC overhead wire (DC feeder) 11 and a wheel 14 grounded through a line 13. 15 are connected in series.

Further, a boost chopper (non-insulated boost choke converter) 16 that boosts the input DC voltage is connected to the subsequent stage of the open contactor 15.
Further, an inverter 17 that converts the boosted DC power, which is the output of the boost chopper 16, into AC power and outputs it is connected to the subsequent stage of the boost chopper 16.

  Here, the inverter 17 sets the frequency of the AC power output from the output terminal to n times (n: an integer of 2 or more, actually several times to several tens times) of the frequency (50 Hz or 60 Hz) of the commercial power source. .

The output terminal of the inverter 17 is connected to the primary side terminal of the transformer 18 that further boosts and outputs the output voltage of the inverter 17 (insulation).
The secondary side terminal of the transformer 18 is connected to a diode rectifier 19 that performs full-wave rectification of the AC power output from the transformer 18 to obtain DC power again.

  Further, a filter 20 configured as an LC filter that removes a high frequency component (noise) from the output of the diode rectifier 19 and outputs it to the load LD is connected to the subsequent stage of the diode rectifier 19.

  The power conversion device 10 has the function of the abnormality detection unit 21X, detects the input current of the control unit 21 that controls the entire power conversion device 10 and the boost chopper 16, and controls the first detection signal SD1. The first current detector 22 as the first detector output to the unit 21 and the output current of the filter 20 (effectively, the output current of the diode rectifier 19) are detected, and the second detection signal SD2 is detected by the control unit 21. And a second current detector 23 as a second detector that outputs to the second current detector.

  In the above configuration, the step-up chopper 16 includes a coil (chopper reactor) 31 connected in series to the open contactor 15, a switching element 32 that performs a chopping operation under the control of the control unit 21, and a backflow prevention diode 33. I have.

  The inverter 17 includes a filter capacitor formed by two capacitors 34 and 35 connected in series, and a switching element 36 (upper arm) and a switching element 37 (lower arm) connected in series. Here, the switching element 36 and the switching element 37 are formed of a gallium nitride (GaN: gallium nitride) semiconductor, which is a material having a wide band gap as compared with silicon (Si).

  The transformer 18 converts the AC power output from the inverter 17 at a step-up ratio corresponding to the turn ratio of the primary coil and the secondary coil (not shown) and outputs the converted power to the subsequent diode rectifier 19. Here, since the primary side and the secondary side of the transformer 18 are insulated, the power conversion device 10 is configured as an insulated DC / DC converter.

The diode rectifier 19 includes diodes 41 and 42 constituting an upper arm and diodes 43 and 44 constituting a lower arm. The diode 41 and the diode 43 are connected in series, and the diode 42 and the diode 44 are connected in series. ing.
The filter 20 includes a reactor (coil) 51 and a capacitor 52 that constitute an LC filter.

The control unit 21 detects the input / output current of the transformer 18 with a current detector (not shown), and controls the gate voltages of the switching elements 32, 36, and 37 according to the detected current value.
In parallel with this, the controller 21 detects an abnormality of the second current detector 23 based on the first detection signal SD1 and the second detection signal SD2.

  FIG. 2 is an explanatory diagram when the abnormality detection unit according to the first embodiment for detecting an abnormality in the second current detection unit is configured as a logic circuit.

  In the abnormality detection unit 21X of the first embodiment, the second detection signal SD2 is input to the inverting input terminal, and the non-current detection for identifying that the output current from the filter 20 is in the non-current state at the non-inverting input terminal. In a current state in which the first comparator 61 to which the threshold value THnc is input, the first detection signal SD1 is input to the non-inverting input terminal, and the current during normal operation flows as the input current of the boost chopper 16 to the inverting input terminal. The second comparator 62 to which the current detection threshold THc for identifying the input is input, and the outputs of the first comparator 61 and the second comparator 62 are respectively input, and a logical product of these outputs is used to calculate the second current detector. And an AND circuit 63 that outputs an “H” level abnormality detection signal SER when there is an abnormality (when a failure occurs).

  In the above configuration, the current detection threshold THc is set to a higher value compared to the case where there is no loss in consideration of the loss on the circuit (particularly the loss of the inverter 17, the transformer 18 and the diode rectifier 19). Is set.

  Then, in the abnormality detection unit 21X, the input current of the boost chopper 16 corresponding to the second detection signal SD2 exceeds the current value during normal operation corresponding to the current detection threshold THc (= the output of the second comparator 62). = “H”), the output current of the filter 20 corresponding to the first detection signal SD1 is equal to or less than the current amount corresponding to the no-current detection threshold THnc (= the output of the first comparator 61 = “H”). "), An abnormality detection signal SER of" H "level indicating that the second current detector 23 is abnormal is output.

Therefore, the control unit 21 controls the boost chopper 16 and the inverter 17 to stop the power conversion operation when the abnormality detection signal SER = “H”.
As a result, according to the first embodiment, the power conversion device 10 can be effectively and reliably protected.

[2] Second Embodiment FIG. 3 is a schematic configuration block diagram of a power conversion device for a railway vehicle according to a second embodiment.
In FIG. 3, parts that are the same as in the first embodiment of FIG.
3 is different from the power conversion device 10 in FIG. 1 in that it has a function of the abnormality detection unit 21Y and includes a control unit 21A that controls the entire power conversion device 10. Instead of the first current detector 22, a first current detector 71 as a first detector that detects the output current of the inverter 17 and outputs the first detection signal SD11 to the control unit 21A is provided.

FIG. 4 is an explanatory diagram when the abnormality detection unit in the second embodiment for detecting an abnormality in the second current detection unit is configured as a logic circuit.
In FIG. 4, the same parts as those in FIG.

  In the abnormality detection unit 21Y of the second embodiment, the second detection signal SD2 is input to the inverting input terminal, and the non-current detection for identifying that the output current from the filter 20 is in the non-current state at the non-inverting input terminal. The first comparator 61 to which the threshold value THnc is input, the first detection signal SD11 is input to the non-inverting input terminal, and the current at normal operation flows as the output current of the inverter 17 to the inverting input terminal. The second comparator 72 to which the current detection threshold THc1 for identifying this is input, and the outputs of the first comparator 61 and the second comparator 72 are respectively input, and the logical product of these outputs is used to calculate the second current detector 23. And an AND circuit 73 that outputs an “H” level abnormality detection signal SER at the time of abnormality (at the time of failure).

  In the above configuration, the current detection threshold THc1 is compared with the case where there is no loss in the same manner as in the first embodiment in consideration of the loss on the circuit (particularly the loss of the transformer 18 and the diode rectifier 19). Although it is set to a higher value, it is not necessary to consider the loss of the inverter 17, so that it can be set more easily than the setting of the current detection threshold THc of the first embodiment.

  Then, the abnormality detection unit 21Y has the output current (high-frequency current) of the inverter 17 corresponding to the second detection signal SD2 exceeds the current value during normal operation corresponding to the current detection threshold THc1 (= second comparator). When the output of 72 is “H”), the output current of the filter 20 corresponding to the first detection signal SD11 is equal to or less than the amount of current corresponding to the no-current detection threshold THnc (= the output of the first comparator 61). = “H”), an “H” level abnormality detection signal SER indicating that the second current detector 23 is abnormal is output.

Therefore, the control unit 21A controls the boost chopper 16 and the inverter 17 to stop the power conversion operation when the abnormality detection signal SER = “H”.
As a result, according to the second embodiment, the power conversion device 10 can be effectively and reliably protected.

[3] Effect of Embodiment As described above, according to each embodiment, it is possible to easily detect an abnormality (failure) of an output current detector that detects an output current to the load LD of the power conversion device. This can contribute to the stable operation of the power converter.

[4] Modification of Embodiment In the above description, the output current to the load LD of the filter 20 is a non-current when a normal current is detected, either the input current of the boost chopper 16 or the output current (high-frequency current) of the inverter 17. In the detection state, the configuration is such that an abnormality of the second current detector 23 is detected. However, it is possible to provide both the first current detector 22 and the first current detector 71.

  In the above description, the abnormality detection unit 21X and the abnormality detection unit 21Y are configured as logic circuits. However, the functions of the abnormality detection unit 21X and the abnormality detection unit 21Y are software using the control unit 21 or the control unit 21A as a microcomputer. It is also possible to configure.

In this case, the control program executed by the microcomputer may be provided by being incorporated in advance in a ROM or the like.
The control program executed by the microcomputer of the present embodiment is a file in an installable or executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), or the like. You may comprise so that it may record and provide on a readable recording medium.

  Further, the control program executed by the microcomputer of the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the control program executed by the microcomputer of the present embodiment may be configured to be provided or distributed via a network such as the Internet.

  When configured by a program, for example, a boost chopper that boosts DC power supplied from an overhead wire to a predetermined voltage value, an inverter that converts DC power output from the boost chopper into AC power, and the inverter A power converter comprising: a transformer that insulates AC power output from the power supply; a rectifier that rectifies AC power output from the transformer; and an output current detector that detects an output current of the rectifier. A control program for controlling by a computer, the computer comprising means for detecting an input current of the boost chopper, means for detecting an output current of the rectifier, input current of the boost chopper, and output current of the rectifier The control program is made to function as a means for detecting an abnormality of the output current detector based on the above.

  In another example, a boost chopper that boosts DC power supplied from an overhead wire to a predetermined voltage value, an inverter that converts DC power output from the boost chopper into AC power, and output from the inverter A computer controls a power conversion device including a transformer that insulates AC power, a rectifier that rectifies AC power output from the transformer, and an output current detector that detects an output current of the rectifier. A control program for detecting the output current of the inverter, the means for detecting the output current of the rectifier, the output current of the inverter and the output current of the rectifier This is a control program that functions as a means for detecting an abnormality in the current detection unit.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10, 10A Power converter 11 Overhead wire 16 Boost chopper 17 Inverter 18 Transformer 19 Diode rectifier 20 Filter 21, 21A Control part 21X, 21Y Abnormality detection part 22, 71 1st current detector 23 2nd current detector (output current detector) )
61 1st comparator 62, 72 2nd comparator 63, 73 AND circuit LD Load SD1, SD11 1st detection signal SD2 2nd detection signal SER Abnormality detection signal THc, THc1 Current detection threshold THnc No current detection threshold

Claims (6)

A step-up chopper that boosts the DC power supplied from the overhead line to a predetermined voltage value;
An inverter that converts DC power output from the boost chopper into AC power;
A transformer that insulates AC power output from the inverter;
A rectifying unit that rectifies AC power output from the transformer and outputs the rectified power to a load;
A first current detector for detecting an input current of the boost chopper and outputting a first detection signal;
A second current detector for detecting an output current of the rectifier and outputting a second detection signal;
Based on the first detection signal and the second detection signal, when the first detection signal is in a current detection state and the second detection signal is in a current non-detection state, the second current detection unit is abnormal. An anomaly detector that detects that there is,
The power converter provided with. A step-up chopper that boosts the DC power supplied from the overhead line to a predetermined voltage value;
An inverter that converts DC power output from the boost chopper into AC power;
A transformer that insulates AC power output from the inverter;
A rectifying unit that rectifies AC power output from the transformer and outputs the rectified power to a load;
A first current detector for detecting an output current of the inverter and outputting a first detection signal;
A second current detector for detecting an output current of the rectifier and outputting a second detection signal;
Based on the first detection signal and the second detection signal, when the first detection signal is in a current detection state and the second detection signal is in a current non-detection state, the second current detection unit is abnormal. An anomaly detector that detects that there is,
The power converter provided with. A controller that controls the boost chopper and the inverter and stops a power conversion operation when the abnormality detector detects that the second current detector is abnormal;
The power converter according to claim 1 or 2. In the inverter, the frequency of the output current of the inverter is n times the commercial power supply frequency (n: an integer of 2 or more).
The power converter device in any one of Claim 1 thru | or 3. A step-up chopper that boosts DC power supplied from an overhead wire to a predetermined voltage value, an inverter that converts DC power output from the boost chopper into AC power, and a transformer that insulates AC power output from the inverter A rectifying unit that rectifies the AC power output from the transformer, and an output current detecting unit that detects an output current of the rectifying unit,
Detecting the input current of the boost chopper;
Detecting the output current of the rectifying unit;
Based on the input current of the boost chopper and the output current of the rectifier, the output current detector is abnormal when the input current of the boost chopper is in a detected state and the output current of the rectifier is in a non-detected state The process of detecting
A method for controlling a power conversion device comprising: A step-up chopper that boosts DC power supplied from an overhead wire to a predetermined voltage value, an inverter that converts DC power output from the boost chopper into AC power, and a transformer that insulates AC power output from the inverter A rectifying unit that rectifies the AC power output from the transformer, and an output current detecting unit that detects an output current of the rectifying unit,
Detecting the output current of the inverter;
Detecting the output current of the rectifying unit;
Based on the output current of the inverter and the output current of the rectifier, the output current detector is abnormal when the input current of the boost chopper is in a detected state and the output current of the rectifier is in a non-detected state. The process of detecting something,
A method for controlling a power conversion device comprising:

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