JP7373424B2 - power converter - Google Patents

Description

The present invention relates to a power conversion device.

Conventionally, power conversion devices have been installed in electric vehicles such as electric vehicles (EVs) and hybrid vehicles (HEVs), and convert DC power supplied from a high-voltage battery into AC power using a switching element, which is then output to a three-phase AC motor. Widely adopted. Such a power conversion device is electrically disconnected from the high-voltage battery in order to safely stop the vehicle when it becomes difficult to maintain normal operation due to a failure or the like. At this time, switching to a three-phase short-circuit operation in which switching elements of all phases of the upper arm or lower arm are turned on is used to circulate current within the motor and prevent voltage rise due to induced voltage.

Patent Document 1 below describes a plurality of driver circuits that are provided corresponding to each switching element and output gate signals for driving each switching element, and a transformer to supply power to each driver circuit. Disclosed is a power conversion device that employs a centralized power supply method in which transformers for six upper and lower arms are shared in the power supply circuit.

Japanese Patent Application Publication No. 2012-186871

In the power conversion device described in Patent Document 1, if the secondary side circuit of the transformer corresponding to any arm in the power supply circuit has a short-circuit failure, the load on the entire power supply circuit increases. The power supply voltage will also drop. As a result, it becomes impossible to drive the switching element, and it becomes impossible to shift to three-phase short circuit operation, which may make it difficult to stop the vehicle safely.

A power conversion device according to the present invention converts DC power into AC power, and includes a plurality of switching elements, a plurality of driver circuits that respectively drive the plurality of switching elements, and a power supply to the plurality of driver circuits. a power supply circuit, the power supply circuit having a primary winding common to the plurality of driver circuits, and a plurality of secondary windings respectively corresponding to the plurality of driver circuits; a current control circuit that controls a current flowing through a primary winding; and a current cutoff circuit that conducts or interrupts a current path between the secondary winding and the driver circuit; When a short-circuit failure occurs, the current cutoff circuit connected to the failed driver circuit cuts off a current path between the failed driver circuit and the secondary winding, and the current cutoff circuit: a first semiconductor switching element that conducts or interrupts current between one end of the secondary winding and the driver circuit; and a control terminal of the first semiconductor switching element and the other end of the secondary winding. and a first resistance element connected between a control terminal of the second semiconductor switching element and one end of the secondary winding.

According to the present invention, it is possible to provide a power conversion device that can shift to a three-phase short-circuit operation even if a short-circuit failure occurs in the secondary circuit of a transformer corresponding to any arm in a power supply circuit.

1 is a diagram showing the configuration of a power conversion device according to an embodiment of the present invention. 1 is a diagram showing the configuration of a power supply circuit according to an embodiment of the present invention. 1 is a diagram showing the configuration of a current cutoff circuit and a low voltage protection circuit according to an embodiment of the present invention. FIG. 6 is a diagram illustrating the operation of a current cutoff circuit and a low voltage protection circuit when a transformer secondary circuit corresponding to any arm in the power supply circuit has a short-circuit failure.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an inverter 101, which is a power conversion device according to an embodiment of the present invention. The inverter 101 shown in FIG. 1 converts DC power into AC power, and includes a motor control board 102, a gate drive board 103, an IGBT module 104 having a plurality of IGBTs (Insulated Gate Bipolar Transistors) as switching elements, and a smoothing capacitor. 109 and a current sensor 110. The IGBT module 104 is connected to a high voltage power source 106 for driving a motor, which is a DC power source, through a positive electrode wire 112 and a negative electrode wire 113. Here, the positive wiring 112 is connected to the positive side (high voltage side) of the high voltage power supply 106 via the contactor 107, and the negative wiring 113 is connected to the negative side (low voltage side) of the high voltage power supply 106. Further, the inverter 101 is connected to a three-phase motor 105.

(IGBT module)
In the IGBT module 104, two stages of N-type IGBTs that operate as switching elements are connected in series (totem pole connection) between a positive electrode wiring 112 and a negative electrode wiring 113. Of these two IGBTs, the IGBT connected to the positive wiring 112 side, that is, the high voltage side of the high voltage power supply 106, is called the upper arm, and the IGBT connected to the negative wiring 113 side, that is, the low voltage side of the high voltage power supply 106, is called the upper arm. It is called the lower arm. In order to drive the three-phase motor 105, the inverter 101 requires output for a total of three phases: U phase, V phase, and W phase. Therefore, the IGBT module 104 has three built-in series circuits in which the upper and lower arms are connected in series, and these series circuits corresponding to each phase are connected in parallel to the high voltage power supply 106. In the series circuit of each phase, common terminals connecting the emitter of the upper arm and the collector of the lower arm are respectively connected to the three-phase motor 105 via the output terminal of the inverter 101.

A free wheel diode (FWD) is connected between the collector and emitter of each IGBT of the IGBT module 104, respectively. A cathode of a freewheeling diode is connected to the collector side of the IGBT, and an anode of the freewheeling diode is connected to the emitter side of the IGBT.

The smoothing capacitor 109 is for suppressing fluctuations in DC voltage caused by switching operations performed by each IGBT of the IGBT module 104, and is connected in parallel with the IGBT module 104 between the positive electrode wiring 112 and the negative electrode wiring 113. . That is, the series circuits of the upper and lower arms of the IGBT module 104 are each connected in parallel to the smoothing capacitor 109 with respect to the high voltage power supply 106.

(gate drive board)
The gate drive board 103 has one driver circuit 121 for each IGBT of the IGBT module 104. That is, the gate drive board 103 is provided with six driver circuits 121, of which three correspond to each IGBT on the upper arm, and the remaining three correspond to each IGBT on the lower arm. Furthermore, the gate drive board 103 has a power supply circuit 115.

The power supply circuit 115 generates a power supply voltage based on the DC power supplied from the high-voltage power supply 106, and supplies it to each of the six driver circuits 121. In this way, each driver circuit 121 operates using the power supplied from the power supply circuit 115. Note that details of the power supply circuit 115 will be described later.

Each driver circuit 121 includes gate control signals 108P (gate control signals UP, VP, WP) and 108N (gate control signals UN, VN, WN) that are output from the motor control board 102 to the upper and lower arms of each phase. is input. For example, taking the W-phase of the upper arm as an example, the gate control signal WP of the W-phase of the upper arm is input from the motor control board 102 to the corresponding driver circuit 121.

(Motor control board)
The motor control board 102 is connected to a higher-level control device (not shown), and an operation command for instructing the operating state of the three-phase motor 105 is input from this control device. Furthermore, the magnitude of the current flowing through the three-phase motor 105 detected by the current sensor 110 is input to the motor control board 102 as a current sense signal 111. Based on the operation command and current sense signal 111 thus input, the motor control board 102 generates gate control signals 108P and 108N for controlling the operation of each IGBT of the IGBT module 104, that is, a gate control signal UP for each phase, VP, WP, UN, VN, and WN are output to each driver circuit 121 in the gate drive board 103. Note that these gate control signals output from the motor control board 102 are negative logic, and when the corresponding IGBT is turned off, a 'H' level signal is output, and when the corresponding IGBT is turned on, an 'L' level signal is output from the motor control board 102. are output from each. The motor control board 102 is operated by power supplied from a 12V power supply 100 for a vehicle.

(Inverter operation)
Next, an overview of the operation of inverter 101 will be explained with reference to FIG. In order to switch each IGBT of the IGBT module 104, the inverter 101 sends PWM gate control signals UP and VP indicated by symbols 108P and 108N to six driver circuits 121 from the motor control board 102 to the gate drive board 103. , send WP, UN, VN and WN. Here, since the motor control board 102 and the gate drive board 103 have different reference potentials, transmission and reception of gate control signals between the motor control board 102 and the gate drive board 103 is performed via an insulated signal transmission device such as a coupler. . Each driver circuit 121 applies a voltage between the gate and emitter terminals of the corresponding IGBT based on the input gate control signal to drive switching of the IGBT. In this way, by switching each IGBT of the IGBT module 104 at a predetermined timing, the DC power supplied from the high voltage power supply 106 is converted to AC power, and current flows to the motor 105 through each IGBT to drive the motor 105. be done. At this time, the current flowing through the motor 105 is observed by a current sensor 110 and fed back to the motor control board 102 as a current sense signal 111. Accordingly, the motor control board 102 controls the current flowing to the motor 105 and controls the driving of the motor 105.

(power supply circuit)
FIG. 2 is a diagram showing the configuration of the power supply circuit 115 according to an embodiment of the present invention. As shown in FIG. 2, the power supply circuit 115 employs a centralized power supply system, and includes a transformer 210, a transformer primary circuit 220, a transformer secondary circuit 230, and a feedback circuit 240. The transformer secondary side circuits 230 are provided for each of the upper and lower arms of the U, V, and W phases, and there are six in total. In FIG. 2, the transformer secondary circuit 230 corresponding to the U-phase upper arm is shown by a broken line. Note that FIG. 2 shows an example of the circuit configuration of the power supply circuit 115 that operates in a flyback manner.

(Trance)
The transformer 210 has a primary winding common to the six driver circuits 121 and six secondary windings corresponding to the six driver circuits 121, respectively. The primary winding is connected to the high voltage power supply 106 via a transformer primary circuit 220, and each secondary winding is connected to a corresponding driver circuit 121 via a transformer secondary circuit 230. Further, the transformer 210 has a secondary winding for feedback, and is connected to the feedback circuit 240.

(Transformer primary side circuit)
The transformer primary side circuit 220 controls the primary side current of the transformer 210 so that the voltage output of the feedback circuit 240 becomes a predetermined voltage value. Each transformer secondary circuit 230 rectifies the secondary current of the transformer 210 and supplies power by outputting a DC voltage to the corresponding driver circuit 121, respectively. The feedback circuit 240 outputs a feedback signal to the transformer primary circuit 220 by outputting the same DC voltage as each transformer secondary circuit 230.

The transformer primary side circuit 220 includes a resistance element 221, a control IC 222, a transformer drive FET 223, and a resistance element 224.

The resistance element 221 is provided between the high voltage power supply 106 and the control IC 222, and adjusts the power supply voltage Vcc1 supplied to the control IC 222. The control IC 222 performs PWM control on the transformer drive FET 223 by monitoring the output of the feedback circuit 240. The transformer drive FET 223 performs a switching operation in response to a PWM pulse output from the control IC 222, and controls the current flowing from the high voltage power supply 106 to the primary side of the transformer 210. Resistance element 224 limits the current flowing to the primary side of transformer 210 via transformer drive FET 223.

(Transformer secondary side circuit)
Each transformer secondary circuit 230 includes a rectifier diode 231, a smoothing capacitor 232, a current cutoff circuit 233, and a low voltage protection circuit 234, and outputs DC voltage to the corresponding driver circuit 121 to supply power. conduct. For example, the transformer secondary side circuit 230 corresponding to the U-phase upper arm is connected to the driver circuit 121 that drives the IGBT of the U-phase upper arm, and supplies power to the driver circuit 121. Similarly, the transformer secondary side circuits 230 corresponding to the V-phase upper arm, W-phase upper arm, U-phase lower arm, V-phase lower arm, and W-phase lower arm, respectively, are connected to the driver circuit 121 that drives the IGBT of each of these arms. and supply power to the driver circuit 121.

The rectifier diode 231 charges the smoothing capacitor 232 by passing only one side of the secondary current of the transformer 210 . Smoothing capacitor 232 charges the current flowing through rectifier diode 231 and generates an output voltage to corresponding driver circuit 121 . Current cutoff circuit 233 conducts or cuts off the current path between the secondary winding of transformer 210 and driver circuit 121 based on the output voltage to driver circuit 121 . When the output voltage to the driver circuit 121 is less than a predetermined threshold, the low voltage protection circuit 234 detects the low voltage state, notifies the motor control board 102, and converts the induced voltage of the three-phase motor 105 into the inverter 101. transition to three-phase short-circuit operation to protect the Note that details of the current cutoff circuit 233 and the low voltage protection circuit 234 will be described later.

(feedback circuit)
The feedback circuit 240 includes a rectifier diode 241 and a smoothing capacitor 242.

The rectifying diode 241 and the smoothing capacitor 242 operate similarly to the aforementioned rectifying diode 231 and the smoothing capacitor 232 provided in the transformer secondary side circuit 230, respectively. As a result, a feedback signal corresponding to the output voltage from each transformer secondary circuit 230 to the corresponding driver circuit 121 is output from the feedback circuit 240. The feedback signal output from the feedback circuit 240 is input to the control IC 222 of the transformer primary side circuit 220, and is compared with a predetermined voltage reference value in PWM control of the transformer drive FET 223.

FIG. 3 is a diagram showing the configuration of the current interrupt circuit 233 and the low voltage protection circuit 234 according to an embodiment of the present invention.

(Current cutoff circuit)
As shown in FIG. 3, current cutoff circuit 233 includes resistance elements 301, 302, and 303, and semiconductor switching elements 304 and 305. The semiconductor switching element 304 is a P-type MOSFET, and the semiconductor switching element 305 is an N-type MOSFET. Semiconductor switching elements 304 and 305 each have a source terminal, a drain terminal, and a gate terminal as a control terminal that switches the conduction state between these terminals. Note that the current cutoff circuit 233 may be configured by using a PNP transistor as the semiconductor switching element 304 and an NPN transistor as the semiconductor switching element 305.

Resistance elements 301 and 302 are connected in series between both ends of the secondary winding of transformer 210, forming a voltage divider circuit. The output voltage of the transformer secondary circuit 230 divided by this voltage dividing circuit is input to the gate terminal of the semiconductor switching element 305. Resistance element 303 is connected between the gate terminal of semiconductor switching element 304 and the drain terminal of semiconductor switching element 305.

The semiconductor switching element 304 is connected between one end of the secondary winding of the transformer 210 and the driver circuit 121, and conducts or interrupts current therebetween. A gate terminal of the semiconductor switching element 304 is connected to the other end of the secondary winding of the transformer 210, that is, to the ground potential of the power supply circuit 115 via the resistance element 303 and the semiconductor switching element 305. Therefore, the voltage at the gate terminal of the semiconductor switching element 304 changes depending on the on/off state of the semiconductor switching element 305, and the on/off state of the semiconductor switching element 304 is switched.

The semiconductor switching element 305 is connected between the gate terminal of the semiconductor switching element 304 and the other end of the secondary winding of the transformer 210. The output voltage of the transformer secondary side circuit 230, which has been divided by the voltage dividing circuit of the resistive elements 301 and 302 as described above, is input to the gate terminal of the semiconductor switching element 305. Therefore, the voltage at the gate terminal of the semiconductor switching element 305 changes according to the output voltage of the transformer secondary side circuit 230, and the on/off state of the semiconductor switching element 305 is switched.

(Low voltage protection circuit)
As shown in FIG. 3, the low voltage protection circuit 234 includes resistance elements 311 and 312 and a control IC 313. Resistance elements 311 and 312 are connected in series between one end of the secondary winding of transformer 210 and the ground potential of power supply circuit 115, and constitute a voltage divider circuit. The output voltage of the transformer secondary side circuit 230 divided by this voltage dividing circuit is input to the control IC 313.

The control IC 313 has a Vcc2 terminal, a UVLO-IN terminal, and an FLT terminal. The Vcc2 terminal is an input terminal of the operating power source of the control IC 313, and the output voltage of the transformer secondary side circuit 230 is inputted as the operating power source of the control IC 313. The UVLO-IN terminal is an input terminal for low voltage protection operation, and receives the voltage divided by the voltage dividing circuit described above. The FLT terminal is an output terminal for a low voltage detection signal and is connected to the motor control board 102. Control IC 313 determines whether the output voltage of transformer secondary circuit 230 is less than a predetermined threshold based on the input voltage to the UVLO-IN terminal. As a result, if it is determined that it is less than the threshold value, it is determined that the voltage is in a low voltage state, and a low voltage detection signal is output from the FLT terminal to the motor control board 102. When a low voltage detection signal is input from the control IC 313, the motor control board 102 outputs a gate control signal 108P or 108N to the driver circuit 121 so as to turn on the IGBTs of all phases of the upper arm or the lower arm. Shifts to three-phase short circuit operation.

(Operation at short circuit failure)
Next, the operation of the current cutoff circuit 233 and the low voltage protection circuit 234 when the transformer secondary side circuit 230 corresponding to one of the arms in the power supply circuit 115 is short-circuited will be described with reference to FIG. 4.

FIG. 4A shows an example of a signal waveform at the time of a short circuit failure when the power supply circuit 115 does not include the current cutoff circuit 233, as a comparative example of the present invention. In FIG. 4(a), the input voltage to the Vcc2 terminal of the control IC 313 and the output voltage of the FLT terminal in the transformer secondary circuit 230 in which a short-circuit failure has occurred, and the output voltage of the transformer secondary circuit 230 of the other arm are shown. It shows.

When a short-circuit failure occurs between both ends of the secondary winding of the transformer 210 in the transformer secondary circuit 230 corresponding to one of the arms, as shown in FIG. 4(a), the transformer secondary circuit 230 The input voltage to the Vcc2 terminal of the control IC 313 decreases. As a result, when the input voltage to the Vcc2 terminal becomes less than the predetermined threshold Vfl, the control IC 313 determines that it is in a low voltage state and changes the output voltage of the FLT terminal from the 'H' level to the 'L' level. Outputs low voltage detection signal. At this time, in the comparative example, the entire secondary side of the transformer 210 is in an overload state, so even in the transformer secondary side circuit 230 of the other arm where the short circuit failure has not occurred, the transformer secondary side circuit where the short circuit failure has occurred Similarly to 230, the input voltage to the Vcc2 terminal of the control IC 313, that is, the voltage of the power supply supplied from the transformer secondary circuit 230 to the driver circuit 121 decreases. Therefore, the driver circuit 121 of the other arm cannot operate normally, and it becomes difficult to shift the IGBT module 104 to three-phase short circuit operation.

FIG. 4(b) shows an example of a signal waveform at the time of a short-circuit failure in the power supply circuit 115 of this embodiment. Similarly to FIG. 4(a), in FIG. 4(b), the input voltage to the Vcc2 terminal of the control IC 313 and the output voltage of the FLT terminal in the transformer secondary circuit 230 where the short-circuit failure has occurred, and the transformer secondary of the other arm. The output voltage of the side circuit 230 is shown. Furthermore, the switching states of the semiconductor switching elements 304 and 305 of the current cutoff circuit 233 in the transformer secondary circuit 230 where a short-circuit failure has occurred are shown.

Similarly to the comparative example, in the power supply circuit 115 of this embodiment, if a short-circuit failure occurs between both ends of the secondary winding of the transformer 210 in the transformer secondary side circuit 230 corresponding to any arm, a short-circuit failure occurs between both ends of the secondary winding of the transformer 210. ), the input voltage to the Vcc2 terminal of the control IC 313 included in the transformer secondary circuit 230 decreases. As a result, when the input voltage to the Vcc2 terminal becomes less than the predetermined threshold Vfl, the control IC 313 determines that it is in a low voltage state and changes the output voltage of the FLT terminal from the 'H' level to the 'L' level. Outputs low voltage detection signal.

Furthermore, when the input voltage to the Vcc2 terminal falls below a predetermined threshold value Vtr lower than the threshold value Vfl, the current cutoff circuit 233 operates, and the switching states of the semiconductor switching elements 304 and 305 change from on to off. Then, the overload condition on the secondary side of the transformer 210 is resolved, and the input voltage to the Vcc2 terminal increases as shown in FIG. 4(b). Thereafter, when the input voltage to the Vcc2 terminal exceeds the threshold value Vtr, the switching states of the semiconductor switching elements 304 and 305 change from off to on. As a result, the state returns to the state when the short-circuit failure occurred, and the input voltage to the Vcc2 terminal decreases again.

In the power supply circuit 115 of this embodiment, the above-described operation is repeatedly performed in the current cutoff circuit 233 of the transformer secondary circuit 230 in which a short-circuit failure has occurred, so that the input voltage to the Vcc2 terminal of the control IC 313 increases. The low voltage detection signal is controlled to be within a certain range lower than the threshold value Vfl at which the control IC 313 outputs the low voltage detection signal. As a result, in the transformer secondary circuit 230 of the other arm where the short-circuit failure has not occurred, as shown in FIG. 4(b), the input voltage to the Vcc2 terminal of the control IC 313, that is, A drop in the voltage of the power supply supplied to the driver circuit 121 can be prevented. Therefore, it is possible to protect the driver circuit 121 of the other arm from an overload state and operate it normally, and to shift the IGBT module 104 to three-phase short circuit operation.

According to the embodiment of the present invention described above, the following effects are achieved.

(1) The inverter 101, which is a power conversion device that converts DC power into AC power, includes an IGBT module 104 having a plurality of IGBTs as switching elements, a plurality of driver circuits 121 that respectively drive the plurality of IGBTs, and a plurality of IGBT modules. A power supply circuit 115 that supplies power to the driver circuit 121 is provided. The power supply circuit 115 includes a transformer 210 having a primary winding common to a plurality of driver circuits 121 and a plurality of secondary windings respectively corresponding to the plurality of driver circuits 121, and a current flowing through the primary winding of the transformer 210. It has a transformer primary side circuit 220 to control, and a current cutoff circuit 233 to conduct or cut off the current path between the secondary winding of the transformer 210 and the driver circuit 121. When any of the plurality of driver circuits 121 has a short-circuit failure, the current cutoff circuit 233 connected to the failed driver circuit 121 interrupts the current path between the failed driver circuit 121 and the secondary winding. do. By doing this, even if the transformer secondary side circuit 230 corresponding to any arm in the power supply circuit 115 is short-circuited, the inverter 101 is a power conversion device that can shift to three-phase short-circuit operation. be able to.

(2) The current interrupt circuit 233 includes a semiconductor switching element 304 that conducts or interrupts current between one end of the secondary winding of the transformer 210 and the driver circuit 121, and a semiconductor switching element 304 that conducts or interrupts current between one end of the secondary winding of the transformer 210 and the driver circuit 121, and a gate terminal of the semiconductor switching element 304 and a terminal of the transformer 210. It has a semiconductor switching element 305 connected between the other end of the secondary winding and a resistance element 301 connected between the gate terminal of the semiconductor switching element 305 and one end of the secondary winding of the transformer 210. By doing this, it is possible to realize the current interrupting circuit 233 that can operate reliably with a simple circuit configuration.

(3) The inverter 101 supplies signals for controlling the driving of the plurality of IGBTs of the IGBT module 104 to the plurality of driver circuits 121 from the motor control board 102 and the power supply circuit 115, respectively, which outputs signals to the plurality of driver circuits 121. The low voltage protection circuit 234 detects a low voltage state and notifies the motor control board 102 when the voltage of the power supply becomes less than a predetermined threshold value Vfl. When the voltage of the power supply supplied from the power supply circuit 115 to any one of the plurality of driver circuits 121 becomes less than the threshold value Vtr, which is lower than the threshold value Vfl, the current cutoff circuit 233 connected to the driver circuit 121 is a semiconductor switching circuit. The element 304 and the semiconductor switching element 305 are each switched from a conductive state to a cutoff state to cut off the current path between the driver circuit 121 and the secondary winding of the transformer 210. With this configuration, when any of the plurality of driver circuits 121 has a short-circuit failure, the current cutoff circuit 233 connected to the failed driver circuit 121 can connect the failed driver circuit 121 and the secondary winding. The current path between the two can be reliably cut off.

(4) The current cutoff circuit 233 further includes a resistance element 302 connected between the gate terminal of the semiconductor switching element 305 and the other end of the secondary winding of the transformer 210. Semiconductor switching element 304 and semiconductor switching element 305 are controlled based on the output voltage of a voltage divider circuit configured by resistance element 301 and resistance element 302. With this configuration, it is possible to appropriately adjust the voltage for switching the semiconductor switching element 304 and the semiconductor switching element 305 in the current cutoff circuit 233.

In the above embodiment, an example has been described in which the current cutoff circuit 233 and the low voltage protection circuit 234 are realized by the circuit configuration shown in FIG. 3, but other circuit configurations may be used. For example, in the current cutoff circuit 233, semiconductor switching elements 304 and 305 may be other than P-type MOSFETs and N-type MOSFETs, and a voltage dividing circuit using resistive elements 301 and 302 may not be used. Further, in the low voltage protection circuit 234, the voltage dividing circuit formed by the resistive elements 311 and 312 may not be used, and the low voltage state may be determined using something other than the control IC 313. Furthermore, the functions of the current cutoff circuit 233 and the low voltage protection circuit 234 may be incorporated into another circuit, for example, the driver circuit 121. The current cutoff circuit 233 and the low voltage protection circuit 234 can be realized by any circuit configuration as long as it has the same functions as those described in the above embodiments.

The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above have been described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

The embodiments and modifications described above are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments considered within the technical spirit of the present invention are also included within the scope of the present invention.

100: 12V power supply, 101: Inverter, 102: Motor control board, 103: Gate drive board, 104: IGBT module, 105: 3-phase motor, 106: High voltage power supply, 107: Contactor, 108P, 108N: Gate control signal, 109 : Smoothing capacitor, 110: Current sensor, 115: Power supply circuit, 121: Driver circuit, 210: Transformer, 220: Transformer primary side circuit, 230: Transformer secondary side circuit, 231: Rectifier diode, 232: Smoothing capacitor, 233 : Current cutoff circuit, 234: Low voltage protection circuit, 240: Feedback circuit, 301, 302, 303: Resistance element, 304, 305: Semiconductor switching element, 311, 312: Resistance element, 313: Control IC

Claims (3)

A power conversion device that converts DC power to AC power,
multiple switching elements;
a plurality of driver circuits that respectively drive the plurality of switching elements;
a power supply circuit that supplies power to the plurality of driver circuits;
The power supply circuit is
a power transformer having a primary winding common to the plurality of driver circuits and a plurality of secondary windings respectively corresponding to the plurality of driver circuits;
a current control circuit that controls the current flowing through the primary winding;
a current interrupting circuit that conducts or interrupts a current path between the secondary winding and the driver circuit;
When any of the plurality of driver circuits has a short-circuit failure, the current cutoff circuit connected to the failed driver circuit interrupts a current path between the failed driver circuit and the secondary winding. ,
The current cutoff circuit is
a first semiconductor switching element that conducts or interrupts current between one end of the secondary winding and the driver circuit;
a second semiconductor switching element connected between a control terminal of the first semiconductor switching element and the other end of the secondary winding;
A power conversion device comprising: a first resistance element connected between a control terminal of the second semiconductor switching element and one end of the secondary winding. The power conversion device according to claim 1 ,
a control board that outputs signals for controlling the driving of the plurality of switching elements to the plurality of driver circuits;
a low voltage protection circuit that detects a low voltage state and notifies the control board when the voltage of the power supply supplied from the power supply circuit to each of the plurality of driver circuits becomes less than a predetermined first threshold; Equipped with
the current cutoff circuit that is connected to the driver circuit when the voltage of the power supply supplied from the power supply circuit to any of the plurality of driver circuits becomes less than a second threshold that is lower than the first threshold; The power converter device switches the first semiconductor switching element and the second semiconductor switching element from a conductive state to a cutoff state to cut off a current path between the driver circuit and the secondary winding. The power conversion device according to claim 2 ,
The current interrupting circuit further includes a second resistance element connected between the control terminal of the second semiconductor switching element and the other end of the secondary winding,
The first semiconductor switching element and the second semiconductor switching element are controlled based on the output voltage of a voltage divider circuit configured by the first resistance element and the second resistance element. .

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