JP2017028971A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply unit capable of shutting down a bi-directional current at high speed.SOLUTION: A power supply unit includes a power converter for converting the power of a power supply and outputting to a load, a switch connected between the power supply and power converter, first and second rectifier circuits connected with the path of a current flowing from the power supply to the power converter via the switch, and a switching circuit connected in parallel with at least any one of the first and second rectifier circuits. The first and second rectifier circuits are the circuits conducting a current only in the forward direction, and are connected in series with the current path with their forward directions reversed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply device.

  A DC power supply, a power converter for performing power conversion between DC power supplied by the DC power supply and AC power for driving and controlling the AC motor, a current sensor for measuring a current passing through the power line, and 2. Description of the Related Art There is known a vehicle power supply device that includes an active filter that supplies an AC current to a power line according to a specified current command value. The vehicle power supply device sequentially calculates a compensation current having a polarity opposite to the alternating current component of the input current based on a current measurement value by a current sensor, generates a current command value for generating the compensation current, and uses an active filter to generate the current command value. An alternating current according to the current command value is supplied to the power line (Patent Document 1).

JP 2005-304235 A

  However, the above-described vehicle power supply device has a problem that bidirectional current cannot be interrupted at high speed between the power source and the load in an emergency or the like.

  The problem to be solved by the present invention is to provide a power supply device capable of interrupting bidirectional current at high speed.

  The present invention provides a first rectifier circuit and a second rectifier circuit connected to a current path flowing from a power source to a power converter through a switch, and at least one of the first rectifier circuit and the second rectifier circuit. And the switching circuit connected in parallel to each other, and the first rectifier circuit and the second rectifier circuit are connected in series to the current path with their forward directions opposite to each other.

  According to the present invention, by switching off the switching circuit connected in parallel to the rectifier circuit, each rectification function of the rectifier circuit connected in series functions, so that bidirectional current can be cut off at high speed. There is an effect.

FIG. 1 is a block diagram of a power supply apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram of a power supply device according to a modification of the present invention. FIG. 3 is a block diagram of a power supply device according to a modification of the present invention. FIG. 4 is a block diagram of the power supply apparatus according to the embodiment of the present invention. FIG. 5 is a block diagram of a power supply device according to a modification of the present invention. FIG. 6 is a block diagram of a power supply device according to a modification of the present invention. FIG. 7 is a block diagram of the power supply device according to the embodiment of the present invention. FIG. 8 is a block diagram of a power supply device according to a modification of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram of a power supply apparatus according to an embodiment of the present invention. The power supply device according to the present embodiment is applied to a drive system that drives a load such as a motor. In the following description, a power supply device is described after taking a motor as an example of a load. The load is not limited to the motor but may be another device. In FIG. 1, the circuit symbols of the diodes shown in the parallel circuits 21 and 31 indicate the direction in which the diodes are connected. In other figures, the direction of the diode is represented by a circuit symbol.

  As shown in FIG. 1, the power supply device includes a power supply 10, a switch 20, a power converter 30, a load 40, a controller 100, and a power supply line PN.

  The power supply 10 supplies power to the load 40 via the switch 20 and the power converter 30. The power supply 10 is connected to the input side of the power conversion circuit by a pair of power supply lines PN. The power supply 10 is configured by connecting a plurality of batteries in series or in parallel. The power source 1 has a positive electrode and a negative electrode. The positive electrode of the power supply 10 is connected to the power supply line P, and the negative electrode of the power supply 10 is connected to the power supply line N. The power supply 10 can be charged by the power output from the power converter 30.

  The switch 20 is a relay switch that switches between conduction and interruption of a current flowing between the power supply 10 and the power converter 30. The switch 20 is connected between the power supply 10 and the power converter 30. The switch 20 includes a diode 21a and a switching element 21b. The diode 21a and the switching element 21b are connected in parallel. A parallel circuit 21 including a diode 21 a and a switching element 21 b is connected to the power supply line P. The forward direction of the diode 21 a is opposite to the conduction direction of the current flowing from the power supply 10 toward the power converter 30.

  The switching element 21b is a semiconductor element, and is a transistor such as a MOSFET. The switching element 21b is controlled by the controller 100. The switching element 21b is a normally-off switch. As a result, when the control signal from the controller 100 to the switch 20 is interrupted due to a trouble such as a power supply stop, the power supply 10 and the power converter 30 are electrically disconnected. Can be realized.

  The switch 20 has a diode function by the diode 21a and a switching function by the switching element 21b. The switch 20 conducts a current from the power converter 30 to the power supply 10 and cuts off a current from the power supply 10 to the power converter 30 when the switching element 21b is in an off state. In addition, the switch 20 conducts only the current from the power supply 10 to the power converter 30 when the switching element 21b is in the on state.

  The power converter 30 converts the power of the power supply 10 and outputs it to the load 40. The power converter 30 includes a circuit that converts power, such as an inverter circuit or a converter circuit. In addition, although illustration is abbreviate | omitted in FIG. 1, the power converter 30 has a power converter circuit. Further, when a motor is connected as the load 40, the power converter 30 converts the output power of the motor into alternating current and outputs it to the power supply 10 during regeneration of the motor.

  The power converter 30 has a parallel circuit 31 of a diode 31a and a switching element 31b. A parallel circuit 31 including a diode 31a and a switching element 31b is connected to the power supply line P. The forward direction of the diode 31 a is the same as the conduction direction of the current flowing from the power supply 10 toward the power converter 30. The switching element 31b is a semiconductor element similar to the switching element 21b.

  The power converter 30 has a diode function by the diode 31a and a switching function by the switching element 31b. When the switching element 31b is in an off state, the power converter 30 conducts a current from the power source 10 toward the power converter 30 and cuts off a current flowing from the load 40 toward the power source 10 via the power converter 30. To do. The power converter 30 conducts only the current flowing from the load 40 toward the power supply 10 via the power converter 30 when the switching element 31b is in the on state.

  The load 40 is a motor or the like. The load 40 is driven by output power from the power converter 30.

  The power line P is a wiring that connects the positive electrode of the power source 10 and the load 40. The power supply line N is a wiring that connects the negative electrode of the power supply 10 and the load 40. Among the input / output terminals of the switch 20, the high potential side terminal and the high potential side terminal of the power converter 30 are connected in series to the power supply line P. Further, the low potential side terminal of the input / output terminals of the switch 20 and the low potential side terminal of the input / output terminals of the power converter 30 are connected in series to the power supply line N.

  The controller 100 controls the switch 20 and the power converter 30. The controller 100 controls on / off of the switching element 21b and on / off of the switching element 31b based on a detection value of a sensor (not shown). The sensor is a voltage, current or temperature sensor.

  Next, control of the controller 100 will be described.

  When the controller 100 interrupts the bidirectional current between the power supply 10 and the load 40, for example, in an emergency, both the switching element 21b and the switching element 31b are turned off, and the diodes of the diodes 21a and 31a Operate only the function. Thereby, it can suppress that overcurrent flows into the main circuit (power conversion circuit) etc. of the power converter 30 at the time of emergency.

  The controller 100 controls charging / discharging of the power supply 10. When the power supply 10 is caused to function as a storage battery, the controller 100 manages the charging capacity charged in the power supply 10 using a sensor connected to the power supply 10. When the charging capacity of the power source 10 is higher than a predetermined value, the controller 100 turns on the switching element 21b, turns off the switching element 31b, and allows a current to flow from the power source 10 to the power converter 30, thereby turning off the power source 10. Discharge. On the other hand, when charging the power supply 10 with the electric power generated by the regenerative operation of the load 40, the controller 100 turns off the switching element 21b and turns on the switching element 21b. Thereby, in this embodiment, the parallel circuits 21 and 31 can be operated as a protection function of the power supply 10.

  As described above, in this embodiment, the diode 21a and the diode 31a are reversed in the forward direction and connected in series to the power supply line P, and the switching element 21b and the switching element 31b are respectively connected to the diode 21a and the diode 31a. Connect in parallel. Thereby, in the current path of the power supply line P, the direction of the current flowing in the same direction as the forward direction of the switching element 21a or the direction of the current flowing in the same direction as the forward direction of the switching element 31a can be limited. Direction current can be cut off at high speed. As a result, the safety at the time of failure can be improved. Also, noise can be reduced.

  In the present embodiment, a semiconductor element such as a MOSFET is provided in order to give the parallel circuits 21 and 31 a switching function. Thereby, the current interruption of nanosecond or less is enabled.

  In the present embodiment, a diode 21 a is connected to the switch 20, and a diode 31 a is connected to the power converter 30. Thereby, size reduction is realizable.

  In the present embodiment, the forward direction of the diode 21 a is opposite to the conduction direction of the current flowing from the power supply 10 toward the power converter 30. Thereby, it is possible to supply power from the power supply 10 to the power converter 30 by turning on the switching element 21b, and it is possible to cut off the current bidirectionally by turning off the switching element 21b.

  Moreover, in this embodiment, the switch 20 has the diode 21a and the switching element 21b, and the power converter 30 has the diode 31a and the switching element 31b. Thereby, since ON / OFF of several switching element 21a, 31a can be controlled, respectively, high-speed start-up and high-speed interruption | blocking are enabled.

  In this embodiment, the switching elements 21b and 31b are connected in parallel to the diode 21a and the diode 31a, respectively. However, the switching elements 21b and 31b may be connected in parallel to at least one of the diode 21a and the diode 31a. .

  In addition, in order to give the switch 20 and the power converter 30 with a diode function, the diodes 21a and 31a are connected. However, the diode function is not limited to the diodes 21a and 31a, and any circuit that conducts current only in the forward direction can be used. Other circuits may be used. Moreover, in order to give the switch 20 and the power converter 30 a switching function, the switching elements 21b and 31b are connected. However, the switching function is not limited to the switching elements 21b and 31b, and other switching circuits may be used.

  In order to give the parallel circuit 21 a diode function and a switching function, the diode 21a and the switching element 21b are connected in parallel. However, a parallel circuit may be configured by a semiconductor element having both the diode function and the switching function. For a semiconductor element having both a diode function and a switching function, a transistor having a parasitic diode (built-in diode) such as a MOSFET may be used. Thereby, size reduction is realizable.

  Further, the controller 100 may simultaneously switch on and off the switching element 21b and the switching element 31b when interrupting the current.

  As a modification of the power supply device according to this embodiment, the parallel circuit 21 may be connected to a power supply line N as shown in FIG. FIG. 2 is a block diagram of a power supply device according to a variation of the present embodiment. Thereby, the freedom degree of an example act can be raised by dividing | segmenting the number of parts to each wiring.

  As a modification of the power supply device according to this embodiment, the parallel circuits 21 and 31 may be connected to the power supply line P and the power supply line N, respectively, as shown in FIG. FIG. 3 is a block diagram of a power supply device according to a variation of the present embodiment. As a result, a large number of diode functions and switching functions can be provided, and a redundant circuit can be configured.

  The diode 21a corresponds to the “first rectifier circuit” of the present invention, the diode 31a corresponds to the “second rectifier circuit” of the present invention, and the switching elements 21b and 31b correspond to the “switching circuit” of the present invention. .

<< Second Embodiment >>
FIG. 4 is a block diagram of a power supply device according to another embodiment of the invention. In this example, the configuration of the power converter 30 and the control of the controller 100 are different from those of the first embodiment described above. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

  As illustrated in FIG. 4, the power converter 30 includes a parallel circuit 31, a capacitor 32, a reactor 33, a capacitor 34, and a parallel circuit 35.

  The parallel circuit 31 is connected to the power supply line P between the capacitor 34 and the parallel circuit 35.

  The capacitor 32 smoothes the electric power input from the power supply 10. The capacitor 32 is connected between the power supply line P and the power supply line N on the input side (power supply 10 side) of the power converter 30.

  The reactor 33 is connected to the power supply line P between the capacitor 32 and the parallel circuit 35. The capacitor 34 is connected between the power supply line P and the power supply line N on the output side (load 40 side) of the power converter 30. The capacitor 34 is a high voltage side capacitor, and the capacitor 32 is a low voltage side capacitor.

  The parallel circuit 35 is a circuit similar to the parallel circuit 31. One end of the parallel circuit 35 is connected to the power supply line P at a connection point located between the parallel circuit 31 and the reactor 33. The other end of the parallel circuit 35 is connected to the power supply line N. The forward direction of the diode included in the parallel circuit 35 is a conduction direction of a current flowing from the power supply line N to the power supply line P. The switch included in the parallel circuit 35 is normally on. Thereby, even when the control signal from the controller 100 to the parallel circuit 30 is interrupted due to a trouble such as a power supply stop, the electric charge in the power converter 30 can be discharged.

  A boost chopper circuit is formed by the reactor 33, the diode included in the parallel circuit 31, the switching element included in the parallel circuit 35, and the capacitor 34. The step-down chopper circuit is formed by the switching elements included in the parallel circuit 31, the diodes included in the parallel circuit 35, the reactor 33, and the capacitor 32. That is, the power converter 30 has a voltage step-up / step-down function in addition to the diode function and the switching function. For example, the step-up / step-down function of the power converter 30 can be exhibited by switching the switching element 31b on and off while turning the switching element 21b off.

  Next, control of the controller 100 will be described.

  The controller 100 controls charging / discharging of the capacitor. When performing charge / discharge control of the capacitors 32 and 34, the controller 100 turns off the switching element 21b. The controller 100 detects the voltages of the capacitors 32 and 34 using voltage sensors (not shown) connected to the capacitors 32 and 34, respectively. When the potential difference between the capacitor 34 and the capacitor 32 is higher than a predetermined potential difference, the controller 100 turns on (short-circuits) and turns off the switching element 31b with the switching element included in the parallel circuit 35 turned off. (Open) is switched at an arbitrary cycle. The electric charge of the capacitor 34 on the high voltage side flows to the capacitor 32 on the low voltage side. Further, when the power supply 10 is used as a storage battery, the charge of the capacitor 34 on the high voltage side can be supplied to the power supply 10 via the switch 20. Thereby, the controller 100 performs discharge control of the capacitor 34 and charge control of the capacitor 32.

  When the discharge of the capacitor 34 progresses and the potential difference between the capacitor 34 and the capacitor 32 becomes equal to or smaller than the predetermined potential difference, the controller 100 turns off the switching element 31b. The controller 100 switches the switching elements included in the parallel circuit 35 on and off at an arbitrary cycle while maintaining the switching elements 21b and 31b in the off state. The charge of the capacitor 32 is consumed by the parasitic resistance in the current path. Moreover, when using the power supply 10 as a storage battery, the electric charge of the capacitor | condenser 32 can also be sent to the power supply 10 via the switch 20. FIG. As a result, the controller 100 controls charging of the capacitor 32. Further, when the potential difference between the capacitor 34 and the capacitor 32 becomes higher than a predetermined potential difference due to the discharge of the capacitor 32, the controller 100 executes again the discharge control of the capacitor 34 and the charge control of the capacitor 32 described above. To do.

  As described above, the present embodiment controls on / off of the switching element 31b. Thereby, since pulsation is applied to the current, an inverter function or a converter function can be added to the power converter 30.

  In the present embodiment, the capacitor 34 is discharged by controlling on and off of the switching element 31b. Thereby, the electric charge in the power converter 30 can be discharged efficiently at high speed.

  In the present embodiment, the capacitor 34 is discharged by controlling on / off of the switching element 31b in a state where the switching elements included in the switching element 21b and the parallel circuit 35 are turned off. Thereby, the electric charge of the capacitor | condenser 34 can be discharged efficiently at high speed.

  In this embodiment, a capacitor 32 is connected to the power supply 10 side of the power converter 30, a capacitor 34 is connected to the load 40 side of the power converter 30, and a switching element (parallel) is connected between the capacitor 32 and the capacitor 34. The switching element included in the circuit 35 is connected. Thereby, pulsation can be applied to the current by switching on and off the switching elements included in the parallel circuit 35 with the switching element 21b in the off state. As a result, an inverter function or a converter function can be added to the power converter 30. Furthermore, the conversion range of power converted by the inverter function or the converter function can be widened.

  In the present embodiment, the capacitor 32 is discharged by switching on and off the switching elements included in the parallel circuit 35 with the switching elements 21b and 31b turned off. Thereby, the electric charge of the capacitor | condenser 32 can be discharged efficiently at high speed.

  In addition, the switching cycle when performing the charge / discharge control of the capacitors 32 and 34, the value of the intermediate resistance is appropriately determined depending on the temperature change of the components of the power converter 30, the voltage change of the capacitor, and the current value flowing through the circuit. Change it.

As a modification of the present invention, when the controller 100 performs charge / discharge control of the capacitors 32 and 34, the controller 100 switches on / off of the switching element 31b or on / off of the switching element included in the parallel circuit 35. The conductive resistance of each switching element may be set to an intermediate resistance. The intermediate resistance is a resistance between the ON resistance (resistance when short-circuiting) and the OFF resistance (resistance when opening) of the switching element. As a result, the charges of the capacitors 32 and 34 can be collected and consumed. Further, the discharge of the capacitors 32 and 34 can be adjusted to an appropriate speed.
Note that the controller 100 determines the resistance value of the intermediate resistor as the current conduction time of the switching element 31b, the current value of the switching element 31b, the temperature of the switching element 31b, or the potential difference on the current path in the power converter 30. You may set according to. Thereby, the temperature rise of the switching element 31b can be suppressed. Similarly, the controller 100 determines the resistance value of the intermediate resistor from the passage of the conduction time of the current of the switching element included in the parallel circuit 35, the current value of the switching element included in the parallel circuit 35, and the switching included in the parallel circuit 35. You may set according to the temperature of an element, or the electric potential difference on the electric current path in the power converter 30. FIG. Thereby, the temperature rise of the switching element included in the parallel circuit 35 can be suppressed. The value of the intermediate resistance may be changed as appropriate in accordance with a time change, a current change, a temperature change, or a potential difference change.

  As a modification of the power supply device according to this embodiment, the parallel circuit 21 may be connected to the power supply line N as shown in FIG. FIG. 5 is a block diagram of a power supply device according to a variation of the present embodiment. Thereby, the freedom degree of an example act can be raised by dividing | segmenting the number of parts to each wiring.

  As a modification of the power supply device according to this embodiment, the parallel circuits 21 and 31 may be connected to the power supply line P and the power supply line N, respectively, as shown in FIG. FIG. 6 is a block diagram of a power supply device according to a variation of the present embodiment. As a result, a large number of diode functions and switching functions can be provided, and a redundant circuit can be configured.

  The switching element 21b corresponds to the “first switching circuit” of the present invention, the switching element 31b corresponds to the “second switching circuit” of the present invention, and the switching element included in the parallel circuit 35 corresponds to the “first switching circuit” of the present invention. Corresponds to "3 switching circuits".

<< Third Embodiment >>
FIG. 7 is a block diagram of a power supply device according to another embodiment of the invention. In this example, the configuration of the power converter 30 is different from the first embodiment described above. Other configurations are the same as those of the first embodiment described above, and the descriptions of the first and second embodiments are incorporated as appropriate.

  The switch 20 has a parallel circuit 21 connected to the power supply lines P and N, respectively.

  The power converter 30 converts the DC power of the power source 10 into AC power and outputs the AC power to the load 40. The power converter 30 includes parallel circuits 31 </ b> A to 31 </ b> F and a capacitor 32. Each of the parallel circuits 31A to 31F is a parallel circuit of a switching element and a diode. The switching element is a transistor such as an IGBT. The current conduction direction of the switching element and the diode conduction direction are opposite to each other. Three pairs of circuits (arm circuits) in which two switching elements are connected in series are connected in parallel to the power supply 10, and each pair of switching elements is electrically connected to the three-phase input portion of the load 40. .

  Each diode included in the parallel circuits 31A to 31 has a function similar to that of the diode 31a according to the first embodiment, and each switching element included in the parallel circuits 31A to 31 is switched according to the first embodiment. It has the same function as the element 31b.

  When the controller 100 interrupts bidirectional current between the power supply 10 and the load 40, for example, in an emergency, the controller 100 turns off both the switching element 21b and the switching elements included in the parallel circuits 31A to 31F. Only operate the diode function. Thereby, it can suppress that overcurrent flows into the main circuit (conversion circuit) etc. of the power converter 30 at the time of emergency.

  In addition, when controlling charging / discharging of the capacitor 32, the controller 100 switches on and off the switching elements included in the parallel circuits 31A to 31F with the switching element 21b turned off. Thereby, the electric charge of the capacitor | condenser 32 can be consumed.

  As a modification of the power supply device according to the present embodiment, as shown in FIG. 8, between the connection point of the U phase and the power supply 10, between the connection point of the V phase and the power supply 10, and in the W phase. You may electrically connect between connection points via the parallel circuit 21, respectively. FIG. 8 is a block diagram of a power supply device according to a variation of the present embodiment. In this modification, the capacitor 32 is connected to the load 40 side. When the controller 100 cuts off the bidirectional current between the power supply 10 and the load 40, the controller 100 turns off both the switching elements 21b and the switching elements included in the parallel circuits 31A to 31F, and performs only the diode function. To work. Thereby, it can suppress that overcurrent flows into the main circuit (conversion circuit) etc. of the power converter 30 at the time of emergency.

  The switching elements included in the parallel circuits 31A to 31F correspond to the switching circuit of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Power supply 20 ... Switch 21, 31 ... Parallel circuit 21a, 31a ... Diode 21b, 31b ... Switching element 30 ... Power converter 31, 31A-31F, 35 ... Parallel circuit 32, 34 ... Capacitor 33 ... Reactor 40 ... Load 100: Controller P, N: Power line

Claims (16)

A power converter that converts the power of the power source and outputs it to the load;
A switch connected between the power source and the power converter;
A first rectifier circuit and a second rectifier circuit connected to a current path flowing from the power source to the power converter via the switch;
A switching circuit connected in parallel to at least one of the first rectifier circuit and the second rectifier circuit;
The first rectifier circuit and the second rectifier circuit are circuits that conduct current only in a forward direction, and are connected in series to the current path with their forward directions reversed. The power supply device according to claim 1, wherein the switching circuit includes a semiconductor element. The switch includes the first rectifier circuit;
The power supply device according to claim 1, wherein the power converter includes the second rectifier circuit. The switch includes the first rectifier circuit;
The power supply apparatus according to any one of claims 1 to 3, wherein a forward direction of the first rectifier circuit is opposite to a conduction direction of a current flowing from the power supply toward the power converter. A controller for controlling the switching circuit;
The power converter has a capacitor;
The power supply device according to claim 1, wherein the controller discharges the capacitor by switching on and off of the switching circuit. The switch includes the first rectifier circuit;
The power converter includes the second rectifier circuit;
6. The switching circuit according to claim 1, wherein the switching circuit includes a first switching circuit connected in parallel to the first rectifier circuit and a second switching circuit connected in parallel to the second rectifier circuit. The power supply device according to any one of the above. A controller for controlling the first switching circuit and the second switching circuit;
The power supply device according to claim 6, wherein the controller switches the second switching circuit on and off while the first switching circuit is turned off. A controller for controlling the first switching circuit and the second switching circuit;
The power converter has a capacitor;
The controller discharges the capacitor by setting the conduction resistance of the second switching circuit to an intermediate resistance with the first switching circuit turned off,
The power supply device according to claim 6, wherein the value of the intermediate resistance is a resistance value between an on resistance and an off resistance of the second switching circuit. The controller is
The conduction time of the current flowing through the second switching circuit, the current value of the current flowing through the second switching circuit, the potential difference between the input and output terminals of the second switching circuit, the temperature of the second switching circuit, or the power conversion The power supply device according to claim 8, wherein a resistance value of the intermediate resistor is set according to a potential difference on a current path in the container. The power converter includes a first capacitor connected to the load side and a second capacitor connected to the power supply side,
The switch includes the first rectifier circuit;
The power converter includes the second rectifier circuit and a third switching circuit;
The switching circuit includes a first switching circuit connected in parallel to the first rectifier circuit, and a second switching circuit connected in parallel to the second rectifier circuit,
The power supply device according to claim 1, wherein the third switching circuit is connected between the first capacitor and the second capacitor. A controller for controlling the first switching circuit, the second switching circuit, and the third switching circuit;
The power supply device according to claim 10, wherein the controller discharges the first capacitor by switching on and off the third switching circuit in a state where the first switching circuit and the second switching circuit are turned off. . A controller for controlling the first switching circuit, the second switching circuit, and the third switching circuit;
The power supply device according to claim 10, wherein the controller discharges the second capacitor by switching on and off the second switching circuit in a state in which the first switching circuit and the third switching circuit are turned off. . A controller for controlling the first switching circuit, the second switching circuit, and the third switching circuit;
The controller discharges the first capacitor by setting a conduction resistance of the third switching circuit to an intermediate resistance with the first switching circuit and the second switching circuit turned off,
The power supply device according to claim 10, wherein the value of the intermediate resistance is a resistance value between an on resistance and an off resistance of the third switching circuit. The controller is
The conduction time of the current flowing through the third switching circuit, the current value of the current flowing through the third switching circuit, the potential difference between the input and output terminals of the third switching circuit, the temperature of the third switching circuit, or the power conversion The power supply apparatus according to claim 13, wherein a resistance value of the intermediate resistor is set according to a potential difference on a current path in the container. The switch includes the first rectifier circuit;
The switching circuit includes a first switching circuit connected in parallel to the first rectifier circuit,
The power supply apparatus according to claim 1, wherein the first switching circuit is normally off. The power converter includes the second rectifier circuit;
The switching circuit includes a second switching circuit connected in parallel to the second rectifier circuit,
The power supply device according to claim 10, wherein the third switching circuit is normally on.

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