JP2008029075A - Inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter device capable of properly operating a Z (impedance) source power converting device regardless of the size of load. <P>SOLUTION: A control portion 13 sets a transistor Qin to an OFF state before starting of a short-circuit period which is a period for charging respective reactors L1, L2 of a boosting circuit 10b by shorting any phase of an inverter circuit 10a and maintaining the OFF state during the shortage period. The transistor Qin is set to an ON state after completion of the short-circuit period, that is during discharge period of the respective reactors L1, L2 of the boosting circuit 10b to allow excitation in an opposite direction which is from the boosting circuit 10b to a battery 12 in addition to excitation in a normal direction which is from the battery 12 to the boosting circuit 10b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inverter device.

Conventionally, for example, a first reactor connected to the positive electrode end of a DC power source, a second reactor connected to the negative electrode side of the DC power source, and a connection between the input end of the first reactor and the output end of the second reactor A booster circuit configured to include a first capacitor and a second capacitor connected between an output terminal of the first reactor and an input terminal of the second reactor; and a plurality of phases connected to an output side of the booster circuit A Z (impedance) source power conversion device including an inverter circuit is known (for example, see Patent Document 1).
US Patent Application Publication No. 2003/0231518

By the way, in the power converter according to the above-described prior art, for example, when the DC power source is a non-rechargeable power source such as a fuel cell, it is necessary to prevent the backflow of current from the booster circuit to the DC power source. At this time, the output current (that is, the load current) of the power converter is simply obtained by providing a backflow prevention circuit between the DC power supply and the booster circuit, for example, a diode or the like that is forward from the DC power supply to the booster circuit. When the voltage is relatively small, the current flowing from the DC power supply to the booster circuit via the backflow prevention circuit becomes zero, and the voltage input to the inverter circuit is inverted by inverting the voltage across the first reactor of the booster circuit. This causes a problem that the voltage output from the inverter circuit becomes unstable. In addition, since the backflow of the current is prevented by the backflow prevention circuit, there is a risk that the voltage will rise excessively when each capacitor of the booster circuit is charged excessively.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an inverter device capable of appropriately operating a Z (impedance) source power converter regardless of the size of a load.

  In order to solve the above problems and achieve the object, an inverter device according to a first aspect of the present invention includes a first reactor connected to a positive terminal of a DC power source (for example, the battery 12 in the embodiment). For example, the first reactor L1 in the embodiment, the second reactor connected to the negative electrode end of the DC power supply (for example, the second reactor L2 in the embodiment), and the input end of the first reactor And a first capacitor connected between the first reactor and the output terminal of the second reactor (for example, the first capacitor C1 in the embodiment), and an output terminal of the first reactor and an input terminal of the second reactor A booster circuit (for example, the booster circuit 10b in the embodiment) configured to include a second capacitor (for example, the second capacitor C2 in the embodiment) connected therebetween, and connected to the output side of the booster circuit Double An inverter device comprising a phase inverter circuit (for example, the inverter circuit 10a in the embodiment), wherein the DC power source and the booster circuit are forwardly directed from the DC power source toward the first reactor. And a diode (for example, a diode D in the embodiment) connected in series between the DC power supply and the diode, and switching for switching on and off between the DC power supply and the booster circuit connected in parallel to the diode The switching element is set to an off state before the start of a short period, which is a period for short-circuiting an element (for example, the transistor Qin in the embodiment) and any phase of the inverter circuit, and after the end of the short period And a control means (for example, the control unit 13 in the embodiment) for setting the switching element to an ON state. It is characterized.

  According to the inverter device configured as described above, the switching element is set to the off state before the start of the short period, which is the period for charging each reactor of the booster circuit by short-circuiting any phase of the inverter circuit, and In addition to forward energization from the DC power supply to the booster circuit by maintaining the state during the short period and setting the switching element to the on state after the end of the short period, that is, during the discharge period of each reactor of the booster circuit Further, energization in the reverse direction from the booster circuit to the DC power supply is allowed. For this reason, for example, in a state where the load current is relatively small, the current flowing through the diode between the DC power supply and the booster circuit becomes zero, and the positive / negative of the voltage across each reactor of the booster circuit is prevented from being reversed. can do. As a result, it is possible to prevent the voltage input to the inverter circuit from fluctuating and the voltage output from the inverter circuit from becoming unstable or the capacitors of the booster circuit from being excessively charged.

  Furthermore, in the inverter device according to the second aspect of the present invention, the DC power source is a non-rechargeable type (for example, the fuel cell 41 in the embodiment), and is forward from the DC power source to the diode. Thus, the backflow prevention diode (for example, backflow prevention diode DI in the embodiment) connected in series between the direct current power supply and the diode, the direct current power supply and the backflow prevention connected in series with each other And a chargeable battery (for example, battery 42 in the embodiment) connected in parallel to the diode.

  According to the inverter device having the above configuration, the non-rechargeable DC power supply is prohibited from being supplied from the booster circuit by the backflow prevention diode, and the chargeable capacitor is allowed to be supplied from the booster circuit by the switching element. Therefore, for example, in a state where the load current is relatively small, the current flowing through the diode between the DC power supply and the capacitor and the booster circuit becomes zero, and the positive and negative voltages of both ends of each reactor of the booster circuit are reversed. Can be prevented. As a result, it is possible to prevent the voltage input to the inverter circuit from fluctuating and the voltage output from the inverter circuit from becoming unstable or the capacitors of the booster circuit from being excessively charged.

  In addition, the inverter device according to the third aspect of the present invention includes a first reactor (for example, in the embodiment) connected to the positive terminal of a non-rechargeable DC power source (for example, the fuel cell 41 in the embodiment). The first reactor L1), the second reactor connected to the negative electrode side of the DC power source (for example, the second reactor L2 in the embodiment), the input terminal of the first reactor, and the output of the second reactor And a second capacitor connected between the output terminal of the first reactor and the input terminal of the second reactor, the first capacitor connected between the first reactor (for example, the first capacitor C1 in the embodiment). (For example, the booster circuit 10b in the embodiment) configured with a second capacitor C2 in the embodiment, and a multi-phase inverter circuit connected to the output side of the booster circuit ( For example An inverter device comprising an inverter circuit 10a) according to an embodiment, wherein the inverter device is connected in series between the DC power supply and the booster circuit so as to be forward from the DC power supply to the first reactor. Backflow prevention diode (for example, backflow prevention diode DI in the embodiment), the DC power supply connected in series with each other and the parallel part connected in parallel to the backflow prevention diode, and energization in the parallel part Control means (for example, the control unit 13 in the embodiment) for switching on and off, and the parallel unit is a chargeable capacitor (for example, the capacitor 42 in the embodiment), and from the capacitor A diode (for example, a diode in the embodiment) connected in series between the battery and the booster circuit so as to be in a forward direction toward the first reactor. ) And a switching element (for example, transistor Qin in the embodiment) that is connected in parallel to the diode and switches on and off of energization between the capacitor and the booster circuit. The means sets the switching element in an off state before the start of a short period, which is a period for short-circuiting any phase of the inverter circuit, and sets the switching element in an on state after the end of the short period. It is characterized by.

  According to the inverter device configured as described above, the switching element is set to the off state before the start of the short period, which is the period for charging each reactor of the booster circuit by short-circuiting any phase of the inverter circuit, and The state is maintained during the short period, and after the short period ends, that is, in the discharge period of each reactor of the booster circuit, by setting the switching element to the on state, forward energization from the DC power supply and the capacitor to the booster circuit is performed. In addition, reverse energization from the booster circuit to the capacitor is allowed. For this reason, for example, in a state where the load current is relatively small, the current flowing through the backflow prevention diode between the DC power supply and the booster circuit and the diode between the capacitor and the booster circuit becomes zero, and each reactor of the booster circuit It can be prevented that the positive and negative voltages of both ends are reversed. As a result, it is possible to prevent the voltage input to the inverter circuit from fluctuating and the voltage output from the inverter circuit from becoming unstable or the capacitors of the booster circuit from being excessively charged.

  According to the inverter device of the present invention, for example, in a state where the load current is relatively small, it is possible to prevent the positive and negative voltages of both ends of each reactor of the booster circuit from being reversed. As a result, it is possible to prevent the voltage input to the inverter circuit from fluctuating and the voltage output from the inverter circuit from becoming unstable or the capacitors of the booster circuit from being excessively charged.

Hereinafter, embodiments of an inverter device of the present invention will be described with reference to the accompanying drawings.
The inverter device 10 according to this embodiment includes an inverter circuit 10a that controls a motor 11 such as a brushless DC motor mounted as a drive source on a vehicle such as a three-phase power device, for example, a hybrid vehicle, a fuel cell vehicle, or an electric vehicle. For example, a battery 12 having a circuit 10b and capable of transferring electrical energy to and from the motor 11 is used as a DC power supply, and receives a control command (for example, a gate signal made up of a pulse width modulation signal) input from the control unit 13, and receives the motor 11 drive and regenerative operations are controlled.

  For example, as shown in FIG. 1, the inverter circuit 10 a includes a bridge circuit 21 formed by bridge connection using a plurality of transistor switching elements (for example, IGBT: Insulated Gate Bipolar Mode Transistor).

In the bridge circuit 21, three phase circuits U1, U2, V1, V2, W1, and W2 arranged in two stages constitute three series circuits for each phase, and these three series circuits are connected in parallel. Inverter circuit.
The collector of each phase transistor U1, V1, W1 is connected to the positive terminal 21p, the emitter of each phase transistor U2, V2, W2 is connected to the negative terminal 21n, and the emitter of each phase transistor U1, V1, W1 is The diodes DU1 are connected to the collectors of the phase transistors U2, V2, W2, and the diodes DU1 are arranged in the forward direction from the emitter to the collector between the collectors and the emitters of the phase transistors U1, U2, V1, V2, W1, W2. , DU2, DV1, DV2, DW1, DW2 are connected.

  The inverter circuit 10a includes pulses for turning on / off each phase transistor U1, U2, V1, V2, W1, W2 by pulse width modulation (PWM), that is, each phase transistor U1, U2, V1, V2, A gate signal for controlling conduction (ON) and cutoff (OFF) between the collector and emitter of W1 and W2 is input from the control unit 13 to the gates of the respective phase transistors U1, U2, V1, V2, W1, and W2. .

  The booster circuit 10b includes a first reactor L1 connected to the positive terminal of the battery 12, a second reactor L2 connected to the negative terminal of the battery 12, and an input terminal of the first reactor L1 and an output terminal of the second reactor L2. A so-called Z (impedance) comprising a first capacitor C1 connected between the first capacitor L1 and a second capacitor C2 connected between the output end of the first reactor L1 and the input end of the second reactor L2. Source circuit.

  Between the battery 12 and the booster circuit 10b, a diode D connected in series is provided in the forward direction from the battery 12 toward the first reactor L1, and the battery 12 is connected in parallel to the diode D. There is provided a transistor Qin serving as a switching element for switching on and off between the power supply and the booster circuit 10b according to a gate signal input from the control unit 13. The collector of the transistor Qin is connected to the first reactor L1 of the booster circuit 10b, and the emitter is connected to the positive terminal of the battery 12.

  The control unit 13 performs, for example, feedback control of current on the dq coordinates that form the rotation orthogonal coordinates, and the accelerator opening degree related to the driver's accelerator operation and the on / off of the brake switch related to the driver's brake operation, etc. The target d-axis current and the target q-axis current are calculated from the torque command for the motor 11 input from the external torque command output unit 14 according to each detection signal (for example, accelerator, brake, etc. shown in FIG. 1). The three-phase output voltage is calculated based on the target d-axis current and the target q-axis current, and a PWM signal as a gate signal is input to the inverter circuit 10a according to each phase output voltage, and the inverter 10a is actually used. The d-axis current and the q-axis current obtained by converting the detected values of the phase currents I1u, I1v, I1w supplied from the motor to the motor 11 on the dq coordinate, and the target d-axis current And each deviation between the target q-axis current is controlled to be zero.

For example, when the motor 11 is driven, the control unit 13 includes pulses for turning on / off each switching element of the inverter circuit 10a by pulse width modulation based on each phase output voltage in a sine wave shape and a carrier signal such as a triangular wave. A gate signal (that is, a pulse width modulation signal) that is a switching command is generated. Then, in the inverter circuit 10a, the booster circuit 10b is switched by switching on / off (shut off) states of the phase transistors U1, U2 and V1, V2, and W1, W2 that make a pair for each of the three phases. The DC power supplied from the battery 12 is converted into three-phase AC power and the energization to the stator windings of the three-phase motor 11 is sequentially commutated, so that the stator windings of each phase A U-phase current I1u, a V-phase current I1v, and a W-phase current I1w are energized.
The pulse duty for driving each phase transistor U1, U2 and V1, V2 and W1, W2 on / off by pulse width modulation (PWM), that is, a map (data) of on / off ratio is controlled in advance. Stored in the unit 13.

  For this reason, the control unit 13 includes a current sensor 31 that detects at least any two of the phase currents I1u, I1v, I1w supplied to the motor 11 (for example, a V-phase current Iv, a W-phase current Iw, etc.). It is output from a rotation sensor 32 that detects a detection signal to be output and a rotation angle θ of the rotor of the motor 11 used in, for example, coordinate conversion processing (that is, a rotation angle of the magnetic pole of the rotor from a predetermined reference rotation position). A detection signal output from the power supply voltage sensor 33 for detecting the terminal voltage (power supply voltage) Vs of the battery 12, and an output voltage Vout output from the booster circuit 10b and applied to the inverter circuit 10a. A detection signal output from the output voltage sensor 34 is input.

  Further, the control unit 13 sets the transistor Qin to the off state before the start of the short period, which is a period for short-circuiting any phase of the inverter circuit 10a, and sets the transistor Qin to the on state after the end of the short period. A gate signal for instructing this is input to the gate of the transistor Qin.

The inverter device 10 according to the present embodiment has the above-described configuration. Next, the operation of the inverter device 10 will be described with reference to the accompanying drawings.
In the following description, any one of the first-stage transistors U1, V1, and W1 of the inverter circuit 10a is referred to as a transistor Q1, which is in the same phase as the transistor Q1, and each of the second-phase transistors U2, U2. One of V2 and W2 is a transistor Q2, and when the load (that is, the motor 11) is energized, of the phase transistors U1, V1, and W1 in the first stage, a transistor in a phase different from each transistor Q2, The second-stage transistor Q2 is set to an on state.

First, for example, in step S01 shown in FIG. 2, a gate signal (drive signal) input to the gates of the transistors Q1, Q2, and Qin is obtained.
Next, in step S02, it is determined whether or not each of the transistors Q1 and Q2 is set to an on state.
If this determination is “NO”, the flow proceeds to step S 05 described later.
On the other hand, if the determination is “YES”, the flow proceeds to step S03.

In step S03, it is determined whether or not the transistor Qin is set to an on state.
If this determination result is “NO”, that is, as shown in FIG. 3, it is a short period in which any phase of the inverter circuit 10a is short-circuited, the series of processing is terminated.
On the other hand, if this determination is “YES”, the flow proceeds to step S 04.
In step S04, a gate signal instructing to set the transistor Qin to the off state is output, a short period is started, and a series of processes is completed.

In step S05, it is determined whether or not the transistor Qin is set to an on state.
When this determination result is “YES”, that is, as shown in FIG. 3, when it is either the zero vector period or the load conduction period, the series of processes is terminated.
On the other hand, if this determination is “NO”, the flow proceeds to step S 06.
In step S06, a gate signal instructing to set the transistor Qin to the on state is output, and the series of processes is terminated.

  For example, as shown in FIG. 4A, in the short period in which any phase of the inverter circuit 10a is short-circuited, the transistors Q1 and Q2 are turned on and the transistor Qin is turned off. As a result, the capacitors C1 and C2 of the booster circuit 10b are set in a discharged state, the reactors L1 and L2 are set in a charged state, and a current is set to flow between the inverter circuit 10a and the booster circuit 10b. Therefore, for example, as shown in FIG. 5A when the load is relatively large and FIG. 5B when the load is relatively small, the both-ends voltage Vc of the capacitors C1 and C2 tends to decrease. The current IL flowing through the reactors L1 and L2 changes in an increasing tendency, and the output voltage Vout applied to the inverter circuit 10a becomes zero.

  For example, as shown in FIG. 4B, when shifting from the short period to the zero vector period in which energization to the motor 11 is prohibited, the transistors Q1 and Qin are turned on, and the transistor Q2 is turned on. It is turned off. As a result, the flow of current between the inverter circuit 10a and the booster circuit 10b is interrupted, and the power supply voltage Vs of the battery 12 is opposite to the short circuit period at both ends of each of the reactors L1 and L2. Voltage VL in the same direction is induced, the reactors L1 and L2 are discharged, the capacitors C1 and C2 of the booster circuit 10b are charged, and from the battery 12 via the diode D to the booster circuit 10b. Is set so that a current flows through. Therefore, for example, as shown in FIGS. 5A and 5B, in the zero vector period, the voltage Vc across the capacitors C1 and C2 changes to increase, and the current IL flowing through the reactors L1 and L2 decreases. The output voltage Vout applied to the inverter circuit 10a is increased so as to increase.

  For example, as shown in FIGS. 4C and 4D, the transistor Q1 is turned off at the time of transition from the zero vector period to the energization (load conduction period) to the load (that is, the motor 11). By turning on the transistors Q2 and Qin, the discharge states of the reactors L1 and L2 and the charge states of the capacitors C1 and C2 are continued. The booster circuit 10b adds the voltage VL across the reactors L1 and L2 to the power supply voltage Vs of the battery 12, and the boosted output voltage Vout (= Vs + VL) is applied to the inverter circuit 10a. The inverter circuit 10a A current is supplied from the motor to the motor 11.

In this load conduction period, for example, as shown in FIG. 5A, when the load is relatively large, that is, when the current supplied to the motor 11 is relatively large, for example, as shown in FIG. As in the load conduction period 1, a current flows from the battery 12 to the booster circuit 10b via the diode D.
On the other hand, as shown in FIG. 5B, for example, when the load is relatively small, that is, when the current supplied to the motor 11 is relatively small, the load conduction period 2 shown in FIG. As described above, a current flows from the booster circuit 10b to the battery 12 through the transistor Qin in the on state.
As a result, in the load conduction period 1 and the load conduction period 2, a both-ends voltage VL in the same direction as the power supply voltage Vs of the battery 12 is induced at both ends of each reactor L1, L2, for example, a zero vector period and a load When the transistor Qin is kept off during the conduction period, the voltage VL in the opposite direction to the power supply voltage Vs of the battery 12 is induced across the reactors L1 and L2 as the current flowing through the diode D becomes zero. Compared with the case where the output voltage Vout applied to the inverter circuit 10a suddenly decreases from (Vs + VL) to (Vc−VL), the output of the inverter circuit 10a can be stabilized.

For example, as shown in FIG. 4 (e), when shifting from the load conduction period to the short period, the transistor Qin is switched from the on state to the off state, and the transistor Q2 is maintained in the on state. The transistor Q1 is switched from the off state to the on state. As a result, in a state in which a current is supplied from the inverter circuit 10a to the motor 11, a both-side voltage VL in the opposite direction to the power source voltage Vs of the battery 12 is induced at both ends of each reactor L1, L2. After a certain load conduction period 3, for example, the above-described short period shown in FIG.
In the load conduction period in which the current IL flowing through each reactor L1, L2 changes in a decreasing trend, for example, as shown in FIG. 5A, the current IL is maintained at a positive value when the load is relatively large. On the other hand, when the load is relatively small as shown in FIG. 5B, for example, the current IL changes smoothly and continuously from a positive value to a negative value. In a short period in which the current IL flowing through each reactor L1, L2 changes in an increasing trend, for example, when the load is relatively large as shown in FIG. 5A, the current IL is maintained at a positive value. On the other hand, for example, when the load is relatively small as shown in FIG. 5B, the current IL changes smoothly and continuously from a negative value to a positive value.

  As described above, according to the inverter device 10 according to the present embodiment, before the start of the short period, which is a period for charging the reactors L1 and L2 of the booster circuit 10b by short-circuiting any phase of the inverter circuit 10a. The transistor Qin is set to the off state, and this off state is maintained during the short period, and the transistor Qin is set to the on state after the end of the short period, that is, in the discharge period of each of the reactors L1 and L2 of the booster circuit 10b. Thus, in addition to forward energization from the battery 12 to the booster circuit 10b, reverse energization from the booster circuit 10b to the battery 12 is allowed. For this reason, for example, in a state where the load current is relatively small, the current flowing through the diode D between the battery 12 and the booster circuit 10b becomes zero, and the positive and negative voltages of both ends of the reactors L1 and L2 of the booster circuit 10b are It is possible to prevent reverse rotation. This prevents the voltage input to the inverter circuit 10a from fluctuating and the voltage output from the inverter circuit 10a from becoming unstable or the capacitors C1 and C2 of the booster circuit 10b from being excessively charged. be able to.

In the above-described embodiment, the inverter device 10 includes the rechargeable battery 12 as a DC power source. However, the present invention is not limited to this, and the inverter device 10 may include a non-rechargeable DC power source such as a fuel cell 41, for example. Good.
The inverter device 10 according to the first modified example includes a fuel cell 41 instead of the battery 12 in the above-described embodiment as shown in FIG. 6, for example, and further forwards from the fuel cell 41 toward the diode D. Thus, the backflow prevention diode DI connected in series between the positive electrode end of the fuel cell 41 and the diode D is connected in parallel to the fuel cell 41 and the backflow prevention diode DI connected in series with each other. The rechargeable battery 42 (for example, a battery or a capacitor) is provided.
In the inverter device 10 according to the first modification, in the load conduction period 2 described above, a current flows from the booster circuit 10b to the battery 42 via the transistor Qin that is on.

Furthermore, in the above-described first modification, the rechargeable battery 42 is connected in parallel to the fuel cell 41 and the backflow prevention diode DI connected in series with each other, but the present invention is not limited to this. As in the inverter device 10 according to the second modification shown in FIG. 7, the parallel part 42 a composed of the battery 42 and the diode D connected in series with each other with respect to the fuel cell 41 and the backflow prevention diode DI connected in series with each other. May be connected in parallel.
In the inverter device 10 according to the second modification, in the load conduction period 2 described above, a current flows from the booster circuit 10b to the battery 42 via the transistor Qin that is on.

It is a block diagram of the inverter apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the inverter apparatus which concerns on embodiment of this invention. It is a figure which shows the on / off state of each transistor Q1, Q2, Qin. 4A to 4E are diagrams showing the flow of current in the inverter device. FIG. 5A is a graph showing an example of a time change of the current IL, the both-end voltage Vc, and the output voltage Vout when the load is relatively large, and FIG. It is a graph which shows an example of the time change of current IL in the case of being small, both-ends voltage Vc, and output voltage Vout. It is a block diagram of the inverter apparatus which concerns on the 1st modification of embodiment of this invention. It is a block diagram of the inverter apparatus which concerns on the 2nd modification of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inverter apparatus 10a Inverter circuit 10b Booster circuit 11 Motor (load)
12 Battery (DC power supply)
13 Control unit 41 Fuel cell (DC power supply)
42 battery

Claims (3)

A first reactor connected to the positive terminal of the DC power source, a second reactor connected to the negative terminal of the DC power source, and a connection between the input terminal of the first reactor and the output terminal of the second reactor A booster circuit configured to include a first capacitor and a second capacitor connected between an output terminal of the first reactor and an input terminal of the second reactor;
An inverter device comprising a plurality of inverter circuits connected to the output side of the booster circuit,
A diode connected in series between the DC power supply and the booster circuit, in a forward direction from the DC power supply toward the first reactor;
A switching element connected in parallel to the diode to switch on and off of energization between the DC power supply and the booster circuit;
Control means for setting the switching element to an off state before the start of a short period, which is a period for short-circuiting any phase of the inverter circuit, and setting the switching element to an on state after the end of the short period; An inverter device comprising the inverter device. The DC power supply is non-rechargeable,
A backflow prevention diode connected in series between the DC power supply and the diode, in a forward direction from the DC power supply toward the diode;
The inverter device according to claim 1, comprising: the DC power supply connected in series to each other; and a chargeable battery connected in parallel to the backflow prevention diode. A first reactor connected to a positive terminal of a non-rechargeable DC power source; a second reactor connected to a negative electrode side of the DC power source; and an input terminal of the first reactor and an output terminal of the second reactor. A booster circuit configured to include a first capacitor connected in between, and a second capacitor connected between an output end of the first reactor and an input end of the second reactor;
An inverter device comprising a plurality of inverter circuits connected to the output side of the booster circuit,
A backflow prevention diode connected in series between the DC power supply and the booster circuit, in a forward direction from the DC power supply to the first reactor;
A parallel section connected in parallel to the DC power supply and the backflow prevention diode connected in series with each other;
Control means for switching energization on and off in the parallel section,
The parallel unit includes a rechargeable battery, a diode connected in series between the battery and the booster circuit so as to be in a forward direction from the battery toward the first reactor, and in parallel with the diode. And a switching element that switches on and off of energization between the capacitor and the booster circuit,
The control means sets the switching element to an off state before the start of a short period, which is a period for short-circuiting any phase of the inverter circuit, and sets the switching element to an on state after the end of the short period. An inverter device characterized by that.

Images