JPWO2013114613A1 - Power converter - Google Patents

Abstract

The power conversion device includes a first diode (D1), a second diode (D2), a first capacitor (C1), a second capacitor (C2), and AC switches (SW1, SW2). Prepare. The first diode (D1) has a cathode terminal connected to the DC positive bus (11). The second diode (D2) has a cathode terminal connected to the anode terminal of the first diode (D1) and an anode terminal connected to the DC negative bus (12). The first capacitor (C1) is connected between the DC positive bus (11) and the neutral point (N1). The second capacitor (C2) is connected between the DC negative bus (12) and the neutral point (N1). The AC switches (SW1, SW2) are connected between the connection point of the first and second diodes (D1, D2) and the neutral point (N1).

Description

  The present invention relates to a power converter.

  A rectifier circuit is a kind of power converter. Various rectifier circuits have been proposed so far. For example, a rectifier circuit disclosed in Japanese Patent Application Laid-Open No. 2006-21867 (Patent Document 1) includes a plurality of diode bridges, a capacitor, and a switching element. The direct current positive terminal and the direct current negative terminal of each diode bridge are connected in common between the plurality of diode bridges. The capacitor and the switching element are connected in parallel between the DC positive terminal and the DC negative terminal of the diode bridge.

  For example, Japanese Unexamined Patent Application Publication No. 2007-329980 (Patent Document 2) and Japanese Unexamined Patent Application Publication No. 2002-142458 (Japanese Patent No. 4051875 (Patent Document 3)) disclose a rectifier circuit including a bidirectional switch. For example, International Publication No. WO2010 / 021052A1 (Patent Document 4) discloses that a three-level circuit is applied to a power conversion device in order to reduce the size and weight of the power conversion device.

JP 2006-2111867 A JP 2007-329980 A JP 2002-142458 A (Patent No. 4051875) International Publication WO2010 / 021052A1

  The semiconductor switching element included in the power converter is, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). When the loss is compared between the MOSFET having the same rating and the IGBT, the loss of the MOSFET is generally smaller than that of the IGBT.

  A MOSFET has a parasitic diode due to its structure. In the case of a power conversion device including a MOSFET, a recovery current flows through a parasitic diode of the MOSFET in the recovery mode. If the recovery current is large, the MOSFET may be damaged. For these reasons, IGBTs are used in many power conversion devices in order to ensure the reliability of the power conversion devices. However, in the case of a power conversion device including an IGBT, efficiency becomes a problem.

  One object of the present invention is to provide a power converter having high efficiency.

  In one aspect of the present invention, a power conversion device includes a first diode, a second diode, a first capacitor, a second capacitor, and an AC switch. The first diode has a cathode terminal connected to the DC positive bus. The second diode has a cathode terminal connected to the anode terminal of the first diode and an anode terminal connected to the DC negative bus. The first capacitor is connected between the DC positive bus and the neutral point. The second capacitor is connected between the DC negative bus and the neutral point. The AC switch is connected between a connection point of the first and second diodes and a neutral point.

  According to the present invention, a power conversion device having high efficiency can be realized.

It is a figure which shows the basic composition of the power converter device which concerns on the 1st implementation form of this invention. It is a figure which shows the power converter device which concerns on the 1st implementation form of this invention. It is a 1st figure for demonstrating generation | occurrence | production of a recovery current. It is a 2nd figure for demonstrating generation | occurrence | production of a recovery current. It is a 3rd figure for demonstrating generation | occurrence | production of a recovery current. 6 is a waveform diagram showing voltages and currents of AC switches S1 and S2 shown in FIGS. FIG. 2 is a first diagram for explaining an operation of a transistor Q3 of the rectifier circuit 1 shown in FIG. FIG. 6 is a second diagram for explaining the operation of the transistor Q3 of the rectifier circuit 1 shown in FIG. FIG. 6 is a third diagram for explaining the operation of the transistor Q3 of the rectifier circuit 1 shown in FIG. FIG. 2 is a first diagram for explaining an operation of a transistor Q4 of the rectifier circuit 1 shown in FIG. FIG. 6 is a second diagram for explaining the operation of the transistor Q4 of the rectifier circuit 1 shown in FIG. FIG. 6 is a third diagram for explaining the operation of the transistor Q4 of the rectifier circuit 1 shown in FIG. It is a figure for demonstrating control of the power converter device 4 shown by FIG. It is a figure explaining operation | movement of the rectifier circuit corresponding to each mode shown in FIG. It is a figure which shows the power converter device which concerns on the 2nd implementation form of this invention. It is the figure which showed the 1st structural example of the power supply device which concerns on the 3rd Embodiment of this invention. It is the figure which showed the 2nd structural example of the power supply device which concerns on the 3rd Embodiment of this invention. It is the figure which showed the 3rd structural example of the power supply device which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a diagram showing a basic configuration of a power conversion device according to the first embodiment of the present invention. Referring to FIG. 1, the power conversion device includes a rectifier circuit 1 and a control circuit 5. The rectifier circuit 1 includes diodes D1 and D2, AC switches SW1 and SW2, and capacitors C1 and C2.

  Diode D1 has a cathode terminal connected to DC positive bus 11 and an anode terminal connected to AC line 2. Diode D <b> 2 has a cathode terminal connected to DC negative bus 12 and an anode terminal connected to AC line 2. In other words, the diodes D1 and D2 are connected in series in the opposite direction between the DC positive bus 11 and the DC negative bus 12. The AC line 2 is connected to a connection point between the diodes D1 and D2.

  Capacitor C1 is connected between DC positive bus 11 and neutral point N1. Capacitor C2 is connected between DC negative bus 12 and neutral point N1. That is, the neutral point N1 is a connection point between the capacitors C1 and C2. The line 3 is connected to the neutral point N1. Line 3 is a neutral line.

  AC switches SW1 and SW2 are connected in series between the connection point of diodes D1 and D2 and neutral point N1. AC switch SW1 includes a transistor Q3 and a diode D3. AC switch SW2 includes a transistor Q4 and a diode D4. Each of transistors Q3 and Q4 is a MOSFET. Transistor Q3 is arranged so that a current flows in the direction from line 3 to AC line 2. On the other hand, transistor Q4 is arranged so that a current flows in the direction from AC line 2 to line 3.

  Diodes D3 and D4 are connected in antiparallel to transistors Q3 and Q4, respectively. Each of transistors Q3 and Q4 has a parasitic diode (not shown). The parasitic diode of the transistor Q3 is formed so that a current flows in the same direction as the diode D3. The parasitic diode of the transistor Q4 is formed so that a current flows in the same direction as the diode D4.

  Control circuit 5 controls switching of each of transistors Q3 and Q4. In this embodiment, a PWM (Pulse Width Modulation) method is adopted as a switching method for the transistors Q3 and Q4. An AC voltage is supplied to the AC line 2. A DC voltage is generated between the DC positive bus 11 and the DC negative bus 12 by the switching of the transistors Q3 and Q4. The voltage of DC positive bus 11 is higher than the voltage of DC negative bus 12.

  FIG. 2 is a diagram showing a power conversion apparatus according to the first embodiment of the present invention. Referring to FIG. 2, power conversion device 4 functions as a three-level PWM converter. The power conversion device 4 includes rectifier circuits 1A, 1B, and 1C and a control circuit 5.

  Each of rectifier circuits 1A, 1B, and 1C has the same configuration as rectifier circuit 1 shown in FIG. Therefore, each of the rectifier circuits 1A, 1B, and 1C includes two diodes (D1A and D2A, D1B and D2B, or D1C and D1C connected in series in the opposite direction between the DC positive bus 11 and the DC negative bus 12. D2C) and two capacitors (C1A and C2A, C1B and C2B, or C1C and C2C) connected in series between the DC positive bus 11 and the DC negative bus 12. Each of the neutral points NA, NB, and NC is a connection point between two corresponding capacitors.

  The rectifier circuit 1A further includes AC switches SW1A and SW2A connected in series between the AC line 2A and the line 3A. The rectifier circuit 1B further includes AC switches SW1B and SW2B connected in series between the AC line 2B and the line 3B. The rectifier circuit 1C further includes AC switches SW1C and SW2C connected in series between the AC line 2C and the line 3C. Each of these AC switches has a transistor (MOSFET) and a diode connected in reverse parallel to the transistor.

  AC lines 2A, 2B, 2C are electrically connected to, for example, a three-phase AC power source (not shown). Lines 3A, 3B, 3C are connected to line 3.

  The control circuit 5 controls the switching of the transistors of each AC switch. As described above, the PWM method is adopted as the switching method of each transistor.

  FIG. 3 is a first diagram for explaining generation of a recovery current. FIG. 4 is a second diagram for explaining the generation of the recovery current. FIG. 5 is a third diagram for explaining the generation of the recovery current.

  Referring to FIGS. 3 to 5, AC switches S <b> 1 and S <b> 2 are connected in series between two terminals of capacitor C. AC switch S1 includes a transistor Q1 and diodes Da and D1. AC switch S2 includes a transistor Q2 and diodes Db and D2. Transistors Q1 and Q2 are MOSFETs. The diodes Da and Db are MOSFET parasitic diodes. Diodes D1 and D2 are connected in antiparallel to transistors Q1 and Q2, respectively. The forward direction of the diode Da is the same as the forward direction of the diode D1. The forward direction of the diode Db is the same as the forward direction of the diode D2.

  When AC switch S1 is on and AC switch S2 is off, current I passes through AC switch S1 (transistor Q1) and reactor L1. Thereby, energy is accumulated in the reactor L1 (FIG. 3). Next, when AC switch S1 is turned off, the energy stored in reactor L1 is discharged from reactor L1 as current I. At this time, the current I flows through the diodes Db and D2 of the AC switch S2 (FIG. 4). Subsequently, the AC switch S1 changes from the off state to the on state. At this time, the current I passes through the AC switch S1 (transistor Q1), flows to the reactor L1, and flows to the diodes Db and D2 (FIG. 5). In the state shown in FIG. 5, the current flowing through the AC switch S2 is the recovery current.

  FIG. 6 is a waveform diagram showing the voltage and current of each of the AC switches S1 and S2 shown in FIGS. Referring to FIG. 6, when AC switch S1 is in the on state and AC switch S2 is in the off state, the voltage applied to AC switch S1 is 0 and a current flows through AC switch S1. At this time, the current flowing through the AC switch S2 is zero.

  When the AC switch S1 changes from the ON state to the OFF state, the voltage applied to the AC switch S1 increases and the current flowing through the AC switch S1 decreases to zero. On the other hand, when the energy accumulated in the reactor L1 is released, a current flows through the diodes Db and D2 of the AC switch S2. For this reason, the current of the AC switch S2 changes from 0 to the negative direction.

  Subsequently, the AC switch S1 changes from the off state to the on state. In this case, the voltage applied to the AC switch S1 decreases to 0, and the current flowing through the AC switch S1 increases. On the other hand, in the AC switch S2, the current flowing through the diodes Db and D2 once exceeds the zero axis and becomes positive, and then decreases to zero. The current in the positive direction surrounded by the broken line is the recovery current. The voltage of the AC switch S2 starts to rise during the generation of the recovery current.

  As shown in FIGS. 3 to 5, the MOSFETs (Q1, Q2) have parasitic diodes (Da, Db). The recovery current flowing through the diode Db may cause the MOSFET (Q2) to turn on unintentionally. In this case, the MOSFET (Q2) may be damaged.

  In general, a snubber circuit is used to prevent such a problem. Alternatively, a wiring having a wide width is used. In this embodiment, the recovery current is prevented from flowing through the AC switch.

  FIG. 7 is a first diagram for explaining the operation of the transistor Q3 of the rectifier circuit 1 shown in FIG. FIG. 8 is a second diagram for explaining the operation of the transistor Q3 of the rectifier circuit 1 shown in FIG. FIG. 9 is a third diagram for explaining the operation of the transistor Q3 of the rectifier circuit 1 shown in FIG.

  7 to 9, when each of transistors Q3 and Q4 is in the on state, current I1 flows out of power supply E1, passes through reactor L1 and transistors Q3 and Q4, and returns to power supply E1 (FIG. 7). 7).

  Next, the transistor Q3 is turned off. Transistor Q4 remains on. In this case, the current I2 flows out of the power supply E1 and passes through the diode D1. The current I2 returns to the power source E1 via the capacitors C1 and C2 (FIG. 8).

  Subsequently, the transistor Q3 changes from the off state to the on state. Transistor Q4 remains on. In this case, the recovery current Ir flows through the diode D1 in the reverse direction. No recovery current flows through the parasitic diodes of the transistors Q3 and Q4. In the case of the operation of the transistors Q1 and Q2 shown in FIG. 4, a forward current flows through the diode Db. For this reason, as shown in FIG. 5, in the recovery mode, a recovery current flows through the diode Db. On the other hand, in the operation of transistors Q3 and Q4 shown in FIGS. 7 and 8, no forward current flowing through the parasitic diodes of transistors Q3 and Q4 is generated. Therefore, no recovery current flows through the parasitic diode in the recovery mode shown in FIG.

  FIG. 10 is a first diagram for explaining the operation of transistor Q4 of rectifier circuit 1 shown in FIG. FIG. 11 is a second diagram for explaining the operation of the transistor Q4 of the rectifier circuit 1 shown in FIG. FIG. 12 is a third diagram for explaining the operation of transistor Q4 of rectifier circuit 1 shown in FIG.

  10 to 12, when each of transistors Q3 and Q4 is in the on state, current I3 flows out of power supply E2 and passes through reactor L2. The current I3 further passes through the transistors Q3 and Q4 via the capacitor C1 and returns to the power supply E2 (FIG. 10).

  Next, the transistor Q4 is turned off. Transistor Q3 remains on. In this case, the current I4 flows out of the power source E2 and passes through the reactor L2. The current I4 further passes through the diode D2 via the capacitors C1 and C2, and returns to the power supply E2 (FIG. 11).

  Subsequently, the transistor Q4 changes from the off state to the on state. Transistor Q3 remains on. In this case, the recovery current Ir flows in the reverse direction through the diode D2. Further, current I5 flows out from power supply E2, passes through reactor L2 and transistors Q3 and Q4, and returns to power supply E2 (FIG. 12). No recovery current flows through the parasitic diodes of the transistors Q3 and Q4. This is because the forward current flowing through the parasitic diodes of the transistors Q3 and Q4 is not generated in the state shown in FIGS.

  As shown in FIGS. 7 to 9, the recovery current does not flow through the AC switches SW1 and SW2 even though the state of the transistor Q3 has changed. Similarly, as illustrated in FIGS. 10 to 12, the recovery current does not flow through the AC switches SW <b> 1 and SW <b> 2 even though the state of the transistor Q <b> 4 has changed.

  FIG. 13 is a diagram for describing control of the power conversion device 4 illustrated in FIG. 2. Referring to FIG. 13, the control of rectifier circuits 1A, 1B, and 1C is the same as each other. Therefore, in FIG. 13, control of any one of the rectifier circuits 1A, 1B, and 1C is shown. The control circuit 5 compares the voltage command signal 103 with the reference signals 101 and 102. The reference signals 101 and 102 and the voltage command signal 103 are generated by the control circuit 5. The voltage command signal 103 is a sine wave signal. The frequency of voltage command signal 103 is equal to the frequency of AC power (for example, 50 Hz or 60 Hz). On the other hand, each of the reference signals 101 and 102 is a triangular wave signal. The frequency of each of the reference signals 101 and 102 is, for example, about 1 kHz to about 10 kHz.

  Mode (1) corresponds to a state in which the voltage command signal 103 is larger than the reference signal 101. Mode (2) corresponds to a state where the voltage command signal 103 is larger than the reference signal 102 and smaller than the reference signal 101. Mode (3) corresponds to a state in which the voltage command signal 103 is smaller than the reference signal 102.

  FIG. 14 is a diagram for explaining the operation of the rectifier circuit corresponding to each mode shown in FIG. As described above, the rectifier circuits 1A, 1B, and 1C are controlled in the same manner. Therefore, in FIG. 14, the rectifier circuit 1 is shown as any one of the rectifier circuits 1A, 1B, and 1C. Referring to FIG. 14, in mode (1), both transistors Q3 and Q4 are turned off. In this case, current flows from AC power supply 10 through reactor L1 and diode D1 to capacitor C1.

  In mode (2), transistors Q3 and Q4 are both turned on. In this case, the current flows from the neutral point N1 to the connection point of the diodes D1 and D2. Alternatively, the current flows in the direction from the connection point of the diodes D1 and D2 to the neutral point N1.

  In mode (3), the transistors Q3 and Q4 are both turned off. In this case, the current flows from the capacitor C2 through the diode D2 and into the AC power supply 10.

  In any of the modes (1) to (3), the recovery current can be prevented from flowing into the AC switches SW1 and SW2.

  The power converter 4 (PWM converter) shown in FIG. 2 is a three-level circuit. Therefore, the power conversion device 4 can convert an AC voltage having three values into a DC voltage. By applying a three-level circuit to the PWM converter, the ripple component generated in the reactor (for example, the reactor L1 in FIG. 14) can be reduced. Since the ripple component is small, the inductance of the reactor may be small. Therefore, the reactor can be reduced in size. Since the reactor can be reduced in size, the power conversion device can be reduced in size and weight.

  In general, in order to realize a three-level circuit, four switching elements connected in series between a DC positive bus and a DC negative bus are required (see, for example, International Publication WO2010 / 021052A1). According to this embodiment, a three-level circuit can be realized by two switching elements. For these reasons, the power converter can be reduced in size and weight.

  Furthermore, according to this embodiment, the recovery current does not flow through the AC switch. When the AC switch is a MOSFET, it is possible to prevent the MOSFET from being damaged due to the recovery current. Therefore, MOSFET can be used for the AC switch. In general, when a MOSFET having the same rating is compared with an IGBT, the switching loss of the MOSFET is smaller than the switching loss of the IGBT. By applying a MOSFET to the AC switch, loss can be reduced. Thereby, the power converter device having high efficiency can be realized.

[Embodiment 2]
FIG. 15 is a diagram illustrating a power conversion device according to the second embodiment of the present invention. Referring to FIG. 15, power conversion device 4A includes transistors Q1A, Q2A, Q1B, Q2B, Q1C, and Q2C in addition to rectifier circuits 1A, 1B, and 1C. The configuration of each of the rectifier circuits 1A, 1B, and 1C is the same as that shown in FIG.

  Each of transistors Q1A, Q2A, Q1B, Q2B, Q1C, and Q2C is an IGBT. Transistors Q1A and Q2A are connected in series between DC positive bus 11 and DC negative bus 12. Transistors Q1B and Q2B are connected in series between DC positive bus 11 and DC negative bus 12. Transistors Q1C and Q2C are connected in series between DC positive bus 11 and DC negative bus 12. The control circuit 5 controls switching of the transistors Q1A, Q2A, Q1B, Q2B, Q1C, and Q2C.

  In the configuration shown in FIG. 15, the diodes D1A and D2A are connected in antiparallel to the transistors Q1A and Q2A, respectively. Diodes D1B and D2B are connected in antiparallel to transistors Q1B and Q2B, respectively. Diodes D1C and D2C are connected in antiparallel to transistors Q1C and Q2C, respectively.

  In general, the power factor of a PWM converter is close to 1.0. Therefore, almost no current flows through the transistors Q1A, Q2A, Q1B, Q2B, Q1C, and Q2C. For this reason, in the power conversion device 4 (PWM converter) shown in FIG. 2, the transistors Q1A, Q2A, Q1B, Q2B, Q1C, and Q2C are omitted from the configuration shown in FIG.

  The power conversion device 4A includes rectifier circuits 1A, 1B, and 1C according to the first embodiment. Therefore, according to this embodiment, the same effect as the power conversion device according to Embodiment 1 can be obtained.

  Furthermore, in this embodiment, an arm is constituted by two transistors connected in series between the DC positive bus 11 and the DC negative bus 12. For example, when a three-phase AC motor is connected to the AC lines 2A, 2B, 2C, the three-phase AC motor can be regenerated. That is, the power conversion device 4A can convert AC power generated by the regenerative operation of the three-phase AC motor into DC power.

[Embodiment 3]
The power supply device according to the third embodiment is realized by the power conversion device according to the first or second embodiment.

  FIG. 16 is a diagram illustrating a first configuration example of the power supply device according to the third embodiment of the present invention. Referring to FIG. 16, power conversion device 4 (or 4A) converts three-phase AC power from AC power supply 10 into DC power. Power converter 4 (or 4A) supplies the DC power to DC load 6 via DC positive bus 11 and DC negative bus 12. Line 3 is connected to AC power supply 10 and DC load 6.

  FIG. 17 is a diagram illustrating a second configuration example of the power supply device according to the third embodiment of the present invention. Referring to FIG. 17, power conversion device 4 (or 4A) converts DC power from DC power supply E into three-phase AC power. DC positive bus 11 and DC negative bus 12 are connected to DC power source E. The power converter 4 (or 4A) supplies the three-phase AC power to the AC load 7 via the AC lines 2A, 2B, and 2C. The AC load 7 is a three-phase four-wire load. Line 3 is connected to AC load 7. As shown in FIG. 17, the power conversion device 4 (or 4A) can be used not only as a converter but also as an inverter (3-level PWM inverter). When the AC load 7 is a three-phase AC motor, it is preferable to use the power conversion device 4A. The power converter 4A can convert the AC power generated by the regenerative operation of the three-phase AC motor into DC power, and supply the DC power to the DC power source E.

  FIG. 18 is a diagram illustrating a third configuration example of the power supply device according to the third embodiment of the present invention. Referring to FIG. 17, power supply device 20 includes a power conversion device 4 and a power conversion device 4B. The configuration of the power conversion device 4B is the same as the configuration of the power conversion device 4. The power conversion device 4 converts the three-phase AC power from the AC power supply 10 into DC power. The power conversion device 4B converts the DC power from the power conversion device 4 into three-phase AC power, and supplies the three-phase AC power to the AC load 7 via the AC lines 22A, 22B, and 22C. The AC load 7 is a three-phase four-wire load. Line 3 is connected to AC power supply 10 and AC load 7.

  In the configuration of FIG. 18, the power conversion device 4 </ b> A can be used instead of the power conversion device 4. In this case, the configuration of power conversion device 4B is, for example, the same as the configuration of power conversion device 4A.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 1A-1C rectifier circuit, 2, 2A-2C, 22A-22C AC line, 3, 3A-3C line (neutral wire), 4, 4A, 4B power converter, 5 control circuit, 6 DC load, 7 AC load, 10 AC power supply, 11 DC positive bus, 12 DC negative bus, 20 power supply, 101, 102 reference signal, 103 voltage command signal, C, C1, C2 capacitor, D1-D4, D1A, D2A, D1B, D2B , D1C, D2C, Da, Db diode, E DC power supply, E1, E2 power supply, I, I1 to I5 current, Ir recovery current, L1, L2 reactor, N1, NA to NC neutral point, Q1 to Q4, Q1A, Q2A, Q1B, Q2B, Q1C, Q2C transistors, S1, S2, SW1, SW2, SW1A, SW2A, SW1B, SW2B, SW1C, W2C AC switch.

Claims (5)

A first diode (D1) having a cathode terminal connected to the DC positive bus (11);
A second diode (D2) having a cathode terminal connected to the anode terminal of the first diode (D1) and an anode terminal connected to the DC negative bus (12);
A first capacitor (C1) connected between the DC positive bus (11) and the neutral point (N1);
A second capacitor (C2) connected between the DC negative bus (12) and the neutral point (N1);
A power converter comprising: an AC switch (SW1, SW2) connected between a connection point of the first and second diodes and the neutral point (N1). The AC switches (SW1, SW2)
First and second MOSFETs (Q3, Q4) connected in series between the connection point of the first and second diodes (D1, D2) and the neutral point (N);
A third diode (D3) antiparallel connected to the first MOSFET;
The power conversion device according to claim 1, further comprising a fourth diode (D4) connected in antiparallel to the second MOSFET. The power converter is
First and second semiconductor switching elements (Q1, Q2) connected in series between the DC positive bus (11) and the DC negative bus (12),
The first diode (D1) is connected in antiparallel to the first semiconductor switching element (Q1),
The power conversion device according to claim 2, wherein the second diode (D2) is connected in antiparallel to the second semiconductor switching element (Q2). The connection point of the first and second diodes (D1, D2) is connected to an AC line (2);
The power converter includes a control circuit for controlling the first and second MOSFETs (Q3, Q4) so that an AC voltage supplied via the AC line (2) is converted into a DC voltage. The power converter according to claim 2, further comprising 5). The connection point of the first and second diodes (D1, D2) is connected to an AC line (2);
The power converter includes the first and second MOSFETs (Q3, Q4) so that a DC voltage supplied via the DC positive bus (11) and the DC negative bus (12) is converted into an AC voltage. The power conversion device according to claim 2, further comprising a control circuit (5) for controlling the).

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