JP2016127680A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable quick and stable stop of a power converter while miniaturizing the power converter.SOLUTION: A power converter has plural combination circuits having boost choppers and inverters. Each boost chopper boosts DC power supplied from a wiring through a current collector to a predetermined voltage value, and the inverter converts the DC power output from the boost chopper to AC power. A line-disconnection compensating capacitor stores power for line-disconnection compensation and supplies power under line disconnection. A discharge resistor is connected to the line-disconnection compensating capacitor in parallel, and discharges power stored in the line-disconnection compensating capacitor when a discharge contactor connected to the discharge resistor in series is set to a close state.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a power conversion apparatus.

  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 facilities (air-conditioning / heating devices, door opening / closing devices, display devices, etc.) Device).

  In such a power converter, the DC power received from the overhead line via the current collector is stabilized to a constant DC voltage by a boost chopper, then converted to AC by a single-phase inverter, and the overhead line and the low voltage are converted by a transformer. There are some which rectify and output DC power to a load after electrically insulating the circuit.

JP-A-6-327261

  By the way, in the conventional power converter, as the switching frequency of the boost chopper is increased, a voltage with less ripple can be obtained even if the capacity of the filter capacitor is reduced. The discharging resistor can also be miniaturized, which can contribute to the miniaturization of the power converter.

  However, if the capacity of the filter capacitor is reduced, the energy stored in the power converter is also reduced. Therefore, if a disconnection occurs when the current collector is temporarily separated due to vibration or the like, the power supply is temporarily (instantly) stopped. An instantaneous power failure occurs, and the output voltage of the power converter is likely to decrease accordingly.

  In order to avoid this, it is necessary to increase the filter capacitor, and the power converter cannot be reduced in size, and in order to stop the power converter quickly and safely, to suppress power loss Therefore, the circuit configuration cannot be simplified.

In order to solve the above-described problem, the power conversion device according to the embodiment includes a plurality of combinational circuits including a boost chopper and an inverter, and each boost chopper is supplied with DC power from an overhead wire via a current collector. Is boosted to a predetermined voltage value, and the inverter converts DC power output from the boost chopper into AC power.
In parallel with this, the capacitor for compensating for the separation is stored with power for compensating the separation, and is supplied at the time of the separation.
In addition, the discharge resistor is connected in parallel with the disconnection compensation capacitor, and the discharge contactor connected in series is closed to discharge the electric power stored in the disconnection compensation capacitor.

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 a schematic configuration block diagram of a power conversion device for a railway vehicle according to the second embodiment.

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, and 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, boost choppers (non-insulated boost choke converters) 16A and 16B for boosting the input DC voltage are connected to the subsequent stage of the open contactor 15.
Further, an inverter 17A for converting the boosted DC power, which is the output of the boost chopper 16A, into AC power and outputting it is connected to the subsequent stage of the boost chopper 16A, and the output of the boost chopper 16B is connected to the subsequent stage of the boost chopper 16B. An inverter 17B that converts DC power after boosting to AC power and outputs the AC power is connected.

Here, the step-up chopper 16A and the inverter 17A constitute a first combination circuit CC1, and the step-up chopper 16B and the inverter 17B constitute a second combination circuit CC2.
In addition, the inverter 17A and the inverter 17B have the frequency of the AC power output from the output terminal n times the frequency of the commercial power supply (50 Hz or 60 Hz) (n: an integer of 2 or more, actually several times to several tens times). And

  Further, the output terminal of the inverter 17A is connected to the primary terminal of a transformer 18A that further boosts and outputs the output voltage of the inverter 17A. The output terminal of the inverter 17B further boosts the output voltage of the inverter 17B. The primary terminal of the transformer 18B that outputs (insulated) is connected.

  The secondary side terminal of the transformer 18A is connected to a diode rectifier circuit 19A that performs full-wave rectification of the AC power output from the transformer 18A and outputs it again as DC power to the load LD, and is connected to the secondary side terminal of the transformer 18B. Is connected to a diode rectifier circuit 19B that performs full-wave rectification of the AC power output from the transformer 18B to generate DC power again, and superimposes it on the output of the diode rectifier circuit 19A and outputs it to the load LD.

  In addition, the power converter 10 is configured to temporarily and instantaneously supply power when the filter coil (filter reactor) 20 that removes high-frequency components of DC power supplied from the DC overhead wire 11 and the pantograph 12 are separated from the DC overhead wire 11. A disconnection compensation capacitor 21 for performing a disconnection compensation for continuing power supply in the event of a momentary power outage that stops automatically, a discharge resistor 22 for consuming power when discharging the disconnection compensation capacitor 21, and a disconnection And a discharge contactor 23 for connecting the discharge resistor 22 to the compensation capacitor 21.

  The power conversion device 10 includes a filter capacitor 24A provided at the subsequent stage of the boost chopper 16A, a discharge resistor 25A connected in parallel to the filter capacitor 24A to dissipate power when discharging the filter capacitor 24A, It has.

  Furthermore, the power conversion device 10 includes a filter capacitor 24B provided at the subsequent stage of the boost chopper 16B, a discharge resistor 25B connected in parallel to the filter capacitor 24B to dissipate power when discharging the filter capacitor 24B, It has.

  In the above configuration, the step-up chopper 16A includes a step-up 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 26, and a backflow prevention diode 33. It is equipped with.

  The step-up chopper 16B shares the step-up chopper 16A and the step-up coil 31 as a chopper reactor, and includes a switching element 32 that performs a chopping operation under the control of the control unit 26, and a backflow prevention diode 33. Yes.

  Further, the inverters 17A and 17B have the same configuration, and are respectively a switching element 34 (upper arm) and a switching element 35 (lower arm) connected in series, and a switching element 36 (upper arm) and switching connected in series. An element 37 (lower arm) is provided. Here, the switching elements 34 to 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 18A converts the AC power output from the inverter 17A at a step-up ratio corresponding to the turn ratio of the primary coil and the secondary coil (not shown), and outputs it to the subsequent diode rectifier circuit 19A. Similarly, the transformer 18B converts the AC power output from the inverter 17B at a step-up ratio corresponding to the turn ratio of the primary coil and the secondary coil (not shown), and outputs it to the subsequent diode rectifier circuit 19B.

  Here, since the primary side and the secondary side of the transformer 18A and the transformer 18B are insulated, the power conversion device 10 is configured as an insulation type DC / DC converter.

  The diode rectifier circuit 19A and the diode rectifier circuit 19B have the same configuration, and include diodes 41 and 42 forming an upper arm and diodes 43 and 44 forming a lower arm, and the diode 41 and the diode 43 are in series. The diode 42 and the diode 44 are connected in series.

The control unit 26 detects input / output currents of the transformers 18A and 18B by a current detector (not shown), and controls the gate voltages of the switching elements 32, 36, and 37 using control signals C1 to C4 according to the detected current values.
Further, the control unit 26 controls the discharge contactor 23 for connecting the discharge resistor 22 to the disconnection compensation capacitor 21 by the control signal C5.

In the above configuration, the line-off compensation capacitor 21 is shared by the boost chopper 16A and the boost chopper 16B. Therefore, it is only necessary to provide one discharge resistor 22.
As a result of this configuration, the capacities of the filter capacitors 24A and 24B can be suppressed to a minimum capacitance according to the switching frequency of the boost choppers 16A and 16B.

  For this reason, the discharge resistor 25A connected in parallel to the filter capacitor 24A and the discharge resistor 25B connected in parallel to the filter capacitor 24B can have a high resistance value and a small current capacity.

As a result, even if the filter capacitor 24A or the filter capacitor 24B is always connected in parallel, the power loss is hardly a problem.
Therefore, since it is not necessary to provide a discharge contactor in series with respect to each of the discharge resistor 25A and the discharge resistor 25B, the circuit configuration can be simplified, and the power converter 10 can be downsized. Can do.

  In addition, by providing the separation compensation capacitor 21, the switching ripple current included in the input currents of the step-up choppers 16A and 16B can be removed. For this reason, the switching ripple current component is not included in the retrace current flowing from the wheel 14 grounded via the track 13, and it can contribute to the stable operation of the railway signal equipment.

  Further, the disconnecting compensation capacitor 21 discharges the stored power and supplies it to the boost choppers 16A and 16B when the pantograph 12 is disconnected from the DC overhead wire 11 due to vibration or the like.

Next, the operation at the normal time (at the time of non-separation) of the first embodiment will be described.
In this case, the two combinational circuits CC <b> 1 and CC <b> 2 constituting the power conversion device 10 perform the same operation in synchronization under the control of the control unit 26.

  When the DC power is supplied from the DC overhead wire (DC feeder) 11 through the pantograph 12, the open contactor 15, and the filter coil 20, the power conversion device 10 supplies DC power to the boost chopper 16A and the boost chopper 16B. The

  Thereby, the control unit 26 compares the preset output instruction voltage with the input DC voltage, and the switching element 32 for making the input DC voltage equal to the output instruction voltage in the two boost choppers 16A and 16B. The control signals C1 and C2 corresponding to the switching frequency and the on-duty are output.

  The switching elements 32 of the step-up choppers 16A and 16B are turned on / off at a switching frequency and on-duty based on the control signals C1 and C2, and the step-up choppers 16A and 16B step up the input DC voltage and corresponding inverters 17A. , 17B, respectively.

  At this time, the output of the boost chopper 16A is output to the inverter 17A after the ripple component and the like are removed by the filter capacitor 24A. Further, the output of the boost chopper 16B is output to the inverter 17B after the ripple component and the like are removed by the filter capacitor 24B.

  Accordingly, in the figure, the inverter 17A converts the boosted DC power, which is the output of the boost chopper 16A from which the ripple component and the like have been removed by the filter capacitor 24A, into AC power based on the control signal C3 output from the control unit 26. And output to the primary side of the transformer 18A.

  Similarly, the inverter 17B converts the boosted DC power, which is the output of the boost chopper 16B from which the ripple component and the like have been removed by the filter capacitor 24B, into AC power based on the control signal C4 output from the control unit 26, thereby converting the transformer. Output to the primary side of 18B.

  Then, the transformer 18A boosts the AC power input to the primary side by a predetermined winding ratio, and outputs it to the corresponding diode rectifier circuit 19A connected to the secondary side while maintaining the insulation state.

Similarly, the transformer 18B boosts the input AC power at a predetermined winding ratio, and outputs it to the corresponding diode rectifier circuit 19B connected to the secondary side while maintaining the insulation state.
The diode rectifier circuit 19A and the diode rectifier circuit 19B convert the input AC power into DC power again and output the DC power.

  As a result, the outputs of the diode rectifier circuit 19A and the diode rectifier circuit 19B are superimposed and supplied to a load (not shown).

In parallel with the above operation, the disconnection compensation capacitor 21 is charged by being supplied with DC power from the DC overhead wire (DC feeder) 11 through the pantograph 12, the open contactor 15, and the filter coil 20, so that the disconnection compensation is performed. The state where the electric power for performing is stored is maintained.
When the power is shut off, the discharge contactor 23 is closed based on the control signal C5 of the control unit 26, and the electric power stored in the disconnection compensation capacitor 21 is discharged via the discharge resistor 22 and consumed. Will be.
Further, as described above, since the capacities of the filter capacitors 24A and 24B are suppressed to the minimum capacitance according to the switching frequency of the boost choppers 16A and 16B, the stored power is discharged from the discharge resistor 25A. , 25B is easily discharged and consumed.

Next, the operation at the time of separation in the first embodiment will be described.
Since the operation up to the separation is the same as the operation at the normal time (at the time of non-separation), the explanation is cited.

A disconnection compensation capacitor 21 that is charged by being supplied with DC power and maintains a state of storing power for performing disconnection compensation is connected to the pantograph 12 that is a current collector from the DC overhead wire (DC feeder) 11. Is separated, the voltages at the input ends of the boost chopper 16A and the boost chopper 16B are lowered, so that the discharge state is entered.
As a result, the circuit subsequent to the boost choppers 16A and 16B can continue the normal operation without being affected by the disconnection.

  As described above, according to the first embodiment, since it is not necessary to provide a discharge contactor in series with each of the discharge resistor 25A and the discharge resistor 25B, the circuit configuration can be simplified. As a result, the power converter 10 can be downsized.

  Further, the provision of the separation compensation capacitor 21 can remove the switching ripple current included in the input currents of the step-up choppers 16A and 16B, thereby contributing to stable operation of railway signal equipment.

  Furthermore, when the pantograph 12 is separated from the DC overhead wire 11 due to vibration or the like, the separation compensation capacitor 21 discharges the stored electric power and boosts the choppers 16A and 16B, and subsequently the inverters 17A and 17B, transformers 18A and 18B, Power can be stably supplied to the diode rectifier circuits 19A and 19B, and stable operation of the load LD can be achieved.

[2] Second Embodiment FIG. 2 is a schematic configuration block diagram of a power conversion device for a railway vehicle according to a second embodiment.
In FIG. 2, the same parts as those in the first embodiment in FIG. 1 are denoted by the same reference numerals.
2 is different from the power conversion device 10 of FIG. 1 in that first, the disconnecting compensation capacitor 21, the discharge resistor 22, and the discharge contactor 23 are not provided.

  Secondly, a discharge resistor 51A and a discharge contactor 52A connected in series with the filter capacitor 24A are provided in parallel with the filter capacitor 24A, and connected in series with the discharge resistor 51B and the discharge resistor 51B in parallel with the filter capacitor 24B. The discharge contactor 52B is provided.

Third, the discharge contactor 52A and the discharge contactor 52B are simultaneously driven by the control coil 53 directly controlled by the control unit 26A.
In the above configuration, the boost chopper 16A and the inverter 17A constitute a first combination circuit CC11, and the boost chopper 16B and the inverter 17B constitute a second combination circuit CC12.

  Further, the filter capacitor 24A and the filter capacitor 24B are set so as to have a sufficient capacity for providing a function of compensating for the separation. Here, in order to shorten the charge discharge time of the filter capacitor 24A and the filter capacitor 24B when the power conversion device 10A is stopped, it is necessary to reduce the resistance values of the discharge resistor 51A and the discharge resistor 51B.

  On the other hand, if the discharge resistor 51A and the discharge resistor 51B having a small resistance value are always connected in parallel to the filter capacitor 24A or the filter capacitor 24B, the power loss increases. In the second embodiment, the discharge contactor 52A and the discharge resistor A contactor 52B is provided.

  By the way, the timing at which the discharge contactor 52A and the discharge contactor 52B should operate may be the same. Therefore, by sharing the control coil 53 that controls the discharge contactor 52A and the discharge contactor 52B, The discharge contactor 52B can be combined into one, and the entire power conversion device is reduced in size.

Next, the normal operation (non-separation) operation of the second embodiment will be described.
In this case, the two combinational circuits CC11 and CC12 configuring the power conversion device 10A perform the same operation in synchronization under the control of the control unit 26A.

  When DC power is supplied from the DC overhead wire (DC feeder) 11 through the pantograph 12 and the open contactor 15, the power conversion device 10A supplies DC power to the boost chopper 16A and the boost chopper 16B.

  Thereby, the control unit 26A compares the output instruction voltage set in advance with the input DC voltage, and the switching element 32 for making the input DC voltage equal to the output instruction voltage in the two step-up choppers 16A and 16B. The control signals C1 and C2 corresponding to the switching frequency and the on-duty are output.

  The switching elements 32 of the step-up choppers 16A and 16B are turned on / off at a switching frequency and on-duty based on the control signals C1 and C2, and the step-up choppers 16A and 16B step up the input DC voltage and corresponding inverters 17A. , 17B, respectively.

  At this time, the output of the boost chopper 16A is output to the inverter 17A after the ripple component and the like are removed by the filter capacitor 24A. Further, the output of the boost chopper 16B is output to the inverter 17B after the ripple component and the like are removed by the filter capacitor 24B.

  Accordingly, in the figure, the inverter 17A converts the boosted DC power, which is the output of the boost chopper 16A from which the ripple component and the like have been removed by the filter capacitor 24A, into AC power based on the control signal C3 output from the control unit 26A. And output to the primary side of the transformer 18A.

  Similarly, the inverter 17B converts the boosted DC power, which is the output of the boost chopper 16B from which the ripple component and the like have been removed by the filter capacitor 24B, into AC power based on the control signal C4 output from the control unit 26A. Output to the primary side of 18B.

  Then, the transformer 18A boosts the AC power input to the primary side by a predetermined winding ratio, and outputs it to the corresponding diode rectifier circuit 19A connected to the secondary side while maintaining the insulation state.

Similarly, the transformer 18B boosts the input AC power at a predetermined winding ratio, and outputs it to the corresponding diode rectifier circuit 19B connected to the secondary side while maintaining the insulation state.
The diode rectifier circuit 19A and the diode rectifier circuit 19B convert the input AC power into DC power again and output the DC power.

  As a result, the outputs of the diode rectifier circuit 19A and the diode rectifier circuit 19B are superimposed and supplied to a load (not shown).

  In parallel with the above operation, the filter capacitor 24A and the filter capacitor 24B are charged by supplying DC power from the DC overhead wire (DC feeder) 11 through the pantograph 12 and the open contactor 15, and perform line-off compensation. The state where the electric power is stored is maintained.

  When the power is shut off, a current is passed through the control coil 53 by the control unit 26A, the discharge contactors 52A and 52B are closed, and the power stored in the filter capacitor 24A and the filter capacitor 24B is discharged to the discharge resistor 51A, It will be discharged and consumed via 51B.

Next, the operation at the time of separation in the second embodiment will be described.
Since the operation up to the separation is the same as the operation at the normal time (at the time of non-separation), the explanation is cited.

The filter capacitor 24A and the filter capacitor 24B, which are charged by being supplied with DC power and maintain the state of storing power for compensating for disconnection, are current collectors from the DC overhead wire 11 (DC feeder) 11. When the pantograph 12 is separated, the voltages at the input terminals of the boost chopper 16A and the boost chopper 16B are lowered, so that the state is shifted to the discharge state.
As a result, the circuit subsequent to the boost choppers 16A and 16B can continue the normal operation without being affected by the disconnection.

  As described above, according to the second embodiment, since the filter capacitor 24A and the filter capacitor 24B store power for compensating for the separation, the stored power is discharged when the pantograph 12 is separated from the DC overhead wire 11 due to vibration or the like. As a result, power can be stably supplied to the boost choppers 16A and 16B, and the subsequent inverters 17A and 17B, the transformers 18A and 18B, and the diode rectifier circuits 19A and 19B, and a stable operation of the load LD can be achieved.

[3] Effects of Embodiments As described above, according to each embodiment, it is possible to obtain a power conversion device for an electric vehicle that does not interrupt power even for a short-time disconnection of a pantograph that is a current collector, Moreover, it can contribute to size reduction and power conversion efficiency improvement of the power converter device for electric vehicles.

[4] Modification of Embodiment Although not described in detail in the above description, the control unit 26 or the control unit 26A may be configured as a logic circuit, or may be configured as a microcomputer. is there.

In this case, the control program executed by the microcomputer as the control unit 26 or the control unit 26A 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 an installable or executable file, and is a computer such as a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk). 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.

  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.

10, 10A Power converter 11 DC overhead line 12 Pantograph (current collector)
13 Line 14 Wheel 15 Open contactor 16A, 16B Step-up chopper 17A, 17B Inverter 18A, 18B Transformer 19A, 19B Diode rectifier circuit 20 Filter coil 21 Decoupling compensation capacitor 22, 25A, 25B, 51A, 51B Discharge resistor 23, 52A , 52B Discharge contactor 24A, 24B Filter capacitor 26, 26A Control unit 31 Boosting coil 32 Switching element 33 Backflow prevention diode 34-37 Switching element 53 Control coil C1-C5 Control signal CC1, CC2, CC11, CC12 Combination circuit LD Load

Claims (4)

A boost chopper that boosts DC power supplied from an overhead wire through a current collector to a predetermined voltage value, and an inverter that converts DC power output from the boost chopper into AC power, and is connected in series A plurality of combined circuits,
A disconnection compensation capacitor that is connected in parallel with the plurality of combinational circuits and stores power for compensation of disconnection,
A discharge resistor connected in parallel with the separation compensation capacitor;
A discharge contactor connected in series with the discharge resistor;
The power converter provided with. A plurality of filter capacitors each connected in parallel with the step-up chopper;
A plurality of filter capacitor discharge resistors connected in parallel with the filter capacitor;
The power converter according to claim 1 provided with. Each of the plurality of boost choppers constituting the plurality of combinational circuits includes switching elements that are driven simultaneously, and performs a boost operation by sharing one boosting coil.
The power converter according to claim 1 or 2. A step-up chopper that boosts DC power supplied from an overhead line through a current collector to a predetermined voltage value; an inverter that converts DC power output from the boost chopper into AC power; A filter capacitor connected in parallel with the step-up chopper in front of the inverter to store power for line-off compensation and filtering the output of the step-up chopper, and a discharge resistor connected in parallel with the filter capacitor And a discharge contactor connected in series with the discharge resistor, comprising a plurality of combinational circuits connected in series,
The discharge contactors constituting the plurality of combinational circuits are simultaneously driven by one control coil.
Power conversion device.

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