JP5065986B2 - Semiconductor device driving apparatus and driving method thereof - Google Patents

Description

  In particular, the present invention relates to a voltage-driven semiconductor device driving device and a driving method thereof.

  In order to avoid the recent problem of global warming, electric powered vehicles are attracting attention. A power-driven vehicle converts DC power supplied from a battery by a power converter into AC power, outputs the AC power to a motor, and drives the motor. In order to suppress the heat generation of this power converter, reduction of switching loss is regarded as important. In order to solve such a problem, for example, a technique of switching by switching the input resistance of an IGBT has been developed (eg, Patent Document 1).

  The drive voltage applied to the gate electrode of the semiconductor element incorporated in the power conversion device is appropriately changed according to the state of the element during the switching operation of the semiconductor element, and a predetermined voltage is detected, whereby the above-described element In a method of driving a semiconductor device that sets the timing of state change, there is a case where it is not necessary to change the voltage applied to the gate of the device depending on the amount of current flowing between the collector and the emitter.

  In addition, setting the gate voltage change timing in the vicinity of a period in which noise is a problem in order to reduce loss is likely to impair switching reliability.

  With the technique described in Patent Document 1, there is a possibility that noise is generated by switching the gate drive voltage regardless of the amount of current flowing between the collector and the emitter during switching. Further, when the timing for switching the drive circuit is determined in advance while avoiding the period in which noise is generated, a large margin must be secured. In the technique described in Patent Document 1, it has not been considered to achieve both sufficient loss reduction and sufficient reliability at the time of switching.

JP-A-9-46201

  The subject of this invention is implement | achieving coexistence of the heat_generation | fever suppression of a power converter device, and the reliability at the time of switching.

  Accordingly, the present invention provides a voltage-driven switching device drive device, wherein the drive circuit unit is electrically connected to the gate electrode of the switching device and applies a gate voltage to the gate electrode, and the gate A voltage detector that detects a gate voltage applied to the electrode; a voltage change rate detector that detects a change rate of the gate voltage applied to the gate electrode; a detection result of the voltage detector and the voltage change rate detection And a control circuit unit that controls the drive circuit unit based on a detection result of the unit to control the drive circuit unit so as to change a gate voltage applied to the gate electrode. provide. As a result, the mirror period of the voltage-driven switching element is detected and the gate voltage is changed according to the mirror period, so that it is possible to achieve both suppression of heat generation and reliability during switching.

  More preferably, the control circuit unit includes a plurality of gate resistance means electrically connected between the drive circuit unit and the gate electrode of the switching element, and the control circuit unit de-energizes a main current passing through the switching element. Comparison result between a gate voltage detected by the voltage detection unit and a predetermined reference voltage after receiving a gate-on signal for switching from a state to a conduction state or a gate-off signal for switching the main current from a conduction state to a non-conduction state And a switching element driving device that determines whether or not to change the electrical connection state of the gate resistance means based on the detection result of the voltage change rate detection unit, and further controls the driving circuit based on the determination result. To do. As a result, the mirror period of the voltage-driven switching element is detected and the gate voltage is changed according to the mirror period, so that it is possible to achieve both suppression of heat generation and reliability during switching.

  More preferably, the control circuit unit receives an effective gate resistance value when the gate voltage is greater than the reference voltage and the detection result of the voltage change rate detector is smaller than a predetermined voltage change rate. Provided is a switching element driving device that determines to change to an electrically connected state of the gate resistance means so that the gate resistance value is larger than before, and controls the driving circuit based on the determination result. Thereby, the reliability at the time of switching of a voltage drive type switching element can be improved especially.

  More preferably, the control circuit unit includes a plurality of gate resistance means electrically connected between the drive circuit unit and the gate electrode of the switching element, and the control circuit unit de-energizes a main current passing through the switching element. A gate voltage detected by the voltage detector after receiving a gate-on signal for switching from the current state to the energized state or a gate-off signal for switching the main current from the energized state to the non-energized state is compared with a predetermined first reference voltage And a switching element driving device for changing the electrical connection state of the gate resistance means so that the effective gate resistance value becomes a first effective gate resistance value larger than that before receiving the gate-on signal based on the comparison result. provide. Thereby, the reliability at the time of switching of a voltage drive type switching element can be improved especially.

  More preferably, after the connection state of the gate resistance means is changed, the control circuit unit compares the gate voltage with a second reference voltage larger than the first reference voltage and the detection result of the voltage change rate detection unit. In accordance with the present invention, there is provided a switching element drive device having a determination unit for determining whether or not to further change the electrical connection state of the gate resistance means. As a result, the mirror period of the voltage-driven switching element is detected and the gate voltage is changed according to the mirror period, so that it is possible to achieve both suppression of heat generation and reliability during switching.

  More preferably, the determination unit determines the effective gate resistance value when the gate voltage is smaller than the second reference voltage and the detection result of the voltage change rate detection unit is smaller than a predetermined voltage change rate. It is determined that the electrical connection state of the gate resistance means is changed so as to be smaller than the effective gate resistance value, and the control circuit unit provides a switching element drive device that controls the drive circuit based on the determination result. Thereby, especially heat_generation | fever suppression can be aimed at.

  More preferably, the determination unit determines the effective gate resistance value when the gate voltage is greater than the second reference voltage and the detection result of the voltage change rate detection unit is less than a predetermined voltage change rate. It is determined that the gate resistance means is changed to an electrical connection state that is maintained or increased to an effective gate resistance value, and the control circuit unit provides a switching element drive device that controls the drive circuit based on the determination result. . Thereby, the reliability at the time of switching of a voltage drive type switching element can be improved especially.

  More preferably, the inverter device for a vehicle includes the above-described switching element drive device, wherein the switching element is an IGBT, and a plurality of upper and lower arms to which the IGBTs are connected in series are connected in parallel. Inverter device for vehicles provided with the made inverter circuit. Thereby, the coexistence of the heat generation suppression of the inverter device and the reliability at the time of switching can be realized.

  According to the present invention, it is possible to realize both suppression of heat generation of the power conversion device and reliability during switching.

  The best mode will be described below with reference to the drawings.

  A power converter according to an embodiment of the present invention will be described below in detail with reference to the drawings. The power conversion device according to the embodiment of the present invention can be applied to a hybrid vehicle or a pure electric vehicle. As a representative example, the power conversion device according to the embodiment of the present invention is applied to a hybrid vehicle. The control configuration and the circuit configuration of the power converter will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a control block of a hybrid vehicle.

  The power conversion device according to the embodiment of the present invention is used in a vehicle-mounted power conversion device for a vehicle-mounted electrical system mounted on an automobile, in particular, a vehicle drive electrical system, and has a very severe mounting environment and operational environment. The inverter device will be described as an example. A vehicle drive inverter device is provided in a vehicle drive electrical system as a control device for controlling the drive of a vehicle drive motor, and a DC power supplied from an onboard battery or an onboard power generator constituting an onboard power source is a predetermined AC power. Then, the AC power obtained is supplied to the vehicle drive motor to control the drive of the vehicle drive motor. Further, since the vehicle drive motor also has a function as a generator, the vehicle drive inverter device also has a function of converting the AC power generated by the vehicle drive motor into DC power according to the operation mode. Yes. The converted DC power is supplied to the on-vehicle battery.

  The configuration of the present embodiment is optimal as a power conversion device for driving a vehicle such as an automobile or a truck. However, other power conversion devices such as a power conversion device such as a train, a ship, and an aircraft, and a factory facility are also included. Applicable to industrial power converters used as drive motor control devices, or household power conversion devices used in home solar power generation systems and motor control devices that drive household appliances It is.

  In FIG. 1, a hybrid electric vehicle (hereinafter referred to as “HEV”) 110 is one electric vehicle and includes two vehicle drive systems. One of them is an engine system that uses an engine 120 that is an internal combustion engine as a power source. The engine system is mainly used as a drive source for HEV. The other is an in-vehicle electric system using motor generators 192 and 194 as a power source. The in-vehicle electric system is mainly used as an HEV drive source and an HEV power generation source. The motor generators 192 and 194 are, for example, synchronous machines or induction machines, and operate as both a motor and a generator depending on the operation method.

  A front wheel axle 114 is rotatably supported at the front portion of the vehicle body. A pair of front wheels 112 are provided at both ends of the front wheel axle 114. A rear wheel axle (not shown) is rotatably supported on the rear portion of the vehicle body. A pair of rear wheels are provided at both ends of the rear wheel axle. The HEV of this embodiment employs a so-called front wheel drive system in which the main wheel driven by power is the front wheel 112 and the driven wheel to be driven is the rear wheel. You may adopt.

  A front wheel side differential gear (hereinafter referred to as “front wheel side DEF”) 116 is provided at the center of the front wheel axle 114. The front wheel axle 114 is mechanically connected to the output side of the front wheel side DEF 116. The output shaft of the transmission 118 is mechanically connected to the input side of the front wheel side DEF 116. The front wheel side DEF 116 is a differential power distribution mechanism that distributes the rotational driving force that is shifted and transmitted by the transmission 118 to the left and right front wheel axles 114. The output side of the motor generator 192 is mechanically connected to the input side of the transmission 118. The output side of the engine 120 and the output side of the motor generator 194 are mechanically connected to the input side of the motor generator 192 via the power distribution mechanism 122. Motor generators 192 and 194 and power distribution mechanism 122 are housed inside the casing of transmission 118.

  The motor generators 192 and 194 are synchronous machines having permanent magnets on the rotor, and the AC power supplied to the armature windings of the stator is controlled by the inverter device 142 to drive the motor generators 192 and 194. Is controlled. A battery 136 is electrically connected to the inverter device 142, and power can be exchanged between the battery 136 and the inverter device 142.

  In the present embodiment, the first motor generator unit including the motor generator 192 and the inverter device 142 and the second motor generator unit including the motor generator 194 and the inverter device 142 are provided, and they are selectively used according to the operating state. ing. That is, in the case where the vehicle is driven by the power from the engine 120, when assisting the driving torque of the vehicle, the second motor generator unit is operated as the power generation unit by the power of the engine 120 to generate power. The first electric power generation unit is operated as an electric unit by the obtained electric power. Further, in the same case, when assisting the vehicle speed of the vehicle, the first motor generator unit is operated by the power of the engine 120 as a power generation unit to generate power, and the second motor generator unit is generated by the electric power obtained by the power generation. Operate as an electric unit.

  In the present embodiment, the vehicle can be driven only by the power of the motor generator 192 by operating the first motor generator unit as an electric unit by the electric power of the battery 136. Furthermore, in the present embodiment, the battery 136 can be charged by generating power by operating the first motor generator unit or the second motor generator unit as the power generation unit by the power of the engine 120 or the power from the wheels.

  The inverter device 142, the inverter device 43, and the capacitor module 500 are in a close electrical relationship. Furthermore, there is a common point that measures against heat generation are necessary. It is also desired to make the volume of the device as small as possible. The power conversion device 1 includes an inverter device 142 and a capacitor module 500 in the casing of the power conversion device 1. With this configuration, a small and highly reliable device can be realized.

  Also, by incorporating the inverter device 142 and the capacitor module 500 in one housing, it is effective in simplifying wiring and taking measures against noise. In addition, the inductance of the connection circuit between the capacitor module 500, the inverter device 142, and the inverter device 43 can be reduced, the spike voltage can be reduced, heat generation can be reduced, and heat dissipation efficiency can be improved.

  Next, the electric circuit configuration of the inverter device 142 will be described with reference to FIG. In the embodiment shown in FIGS. 1 and 2, the case where the inverter devices 142 are individually configured will be described as an example. Since the inverter device 142 has the same structure and performs the same function and has the same function, the inverter device 142 will be described here as a representative example.

  The power conversion device 1 according to the present embodiment includes an inverter circuit unit 140 and a capacitor module 500, and the inverter circuit unit 140 includes an inverter circuit unit 140 and a control unit 170. The inverter circuit unit 140 includes a plurality of upper and lower arm series circuits 150 each including an IGBT 100 (insulated gate bipolar transistor) and a diode 156 that operate as an upper arm, and an IGBT 100 and a diode 156 that operate as a lower arm. It connects with the alternating current power line (alternating current bus bar) to the motor generator 192 through the alternating current terminal from the middle point part of the upper and lower arm series circuit. In addition, the control unit 170 includes a driver circuit 174 that drives and controls the inverter circuit, and a control circuit 172 that supplies a control signal to the driver circuit 174 via the signal line 176.

  The IGBTs 100 of the upper arm and the lower arm are switching power semiconductor elements, operate in response to a drive signal output from the control unit 170, and convert DC power supplied from the battery 136 into three-phase AC power. The converted electric power is supplied to the armature winding of the motor generator 192.

  The inverter circuit unit 140 is configured by a three-phase bridge circuit, and upper and lower arm series circuits for three phases are respectively connected to a positive electrode terminal and a negative electrode terminal that are electrically connected to the positive electrode side and the negative electrode side of the battery 136. They are electrically connected in parallel.

  In this embodiment, using IGBT100 as a power semiconductor element for switching is illustrated. A diode 156 is electrically connected between the collector electrode and emitter electrode of the IGBT 100 as shown. The diode 156 includes two electrodes, a cathode electrode and an anode electrode. The cathode electrode is the collector electrode of the IGBT 100 and the anode electrode is the IGBT 100 so that the direction from the emitter electrode to the collector electrode of the IGBT 100 is the forward direction. Each is electrically connected to the emitter electrode. As the switching power semiconductor element, a MOSFET (metal oxide semiconductor field effect transistor) may be used. In this case, the diode 156 is unnecessary.

  The upper and lower arm series circuits are provided for three phases corresponding to each phase winding of the armature winding of the motor generator 192. Each of the three upper and lower arm series circuits 150 forms a U phase, a V phase, and a W phase to the motor generator 192 via an intermediate electrode and an AC terminal that connect the emitter electrode of the IGBT 100 and the collector electrode of the IGBT 100, respectively. The upper and lower arm series circuits are electrically connected in parallel.

  The collector electrode of the upper arm IGBT 100 is connected to the positive capacitor electrode of the capacitor module 500 via the positive terminal (P terminal), and the emitter electrode of the lower arm IGBT 100 is connected to the negative electrode side of the capacitor module 500 via the negative terminal (N terminal). Each capacitor electrode is electrically connected (connected by a DC bus bar). The intermediate electrode corresponding to the midpoint portion of each arm (the connection portion between the emitter electrode of the IGBT 100 of the upper arm and the collector electrode of the IGBT 100 of the lower arm) is connected to the corresponding phase winding of the armature winding of the motor generator 192 by the AC connector 188. It is electrically connected via.

  Capacitor module 500 is for configuring a smoothing circuit that suppresses fluctuations in DC voltage caused by the switching operation of IGBT 100. A positive electrode side of the battery 136 is electrically connected to the positive electrode side capacitor electrode of the capacitor module 500 and a negative electrode side of the battery 136 is electrically connected to the negative electrode side capacitor electrode of the capacitor module 500 via a DC connector. Thereby, the capacitor module 500 is connected between the collector electrode of the upper arm IGBT 100 and the positive electrode side of the battery 136, and between the emitter electrode of the lower arm IGBT 100 and the negative electrode side of the battery 136. Electrically connected in parallel to the circuit.

  The control unit 170 is for operating the IGBT 100, and based on input information from other control devices and sensors, a control circuit 172 that generates a timing signal for controlling the switching timing of the IGBT 100, and a control circuit And a drive circuit 174 that generates a drive signal for switching the IGBT 100 based on the timing signal output from 172.

  The control circuit 172 includes a microcomputer (hereinafter referred to as “microcomputer”) for calculating the switching timing of the IGBT 100. The microcomputer receives as input information a target torque value required for the motor generator 192, a current value supplied to the armature winding of the motor generator 192 from the upper and lower arm series circuit 150, and a magnetic pole of the rotor of the motor generator 192. The position has been entered. The target torque value is based on a command signal output from a host controller (not shown). The current value is detected based on a detection signal output from a current sensor (not shown). The magnetic pole position is detected based on a detection signal output from a rotating magnetic pole sensor (not shown) provided in the motor generator 192. In the present embodiment, the case where the current values of three phases are detected will be described as an example, but the current values for two phases may be detected.

  The microcomputer in the control circuit 172 calculates the d and q axis current command values of the motor generator 192 based on the target torque value, and the calculated d and q axis current command values and the detected d and q The voltage command values for the d and q axes are calculated based on the difference from the current value of the shaft, and the calculated voltage command values for the d and q axes are calculated based on the detected magnetic pole position. Convert to W phase voltage command value. Then, the microcomputer generates a pulse-like modulated wave based on the comparison between the fundamental wave (sine wave) and the carrier wave (triangular wave) based on the voltage command values of the U-phase, V-phase, and W-phase, and the generated modulation The wave is output to the driver circuit 174 as a PWM (pulse width modulation) signal.

  When driving the lower arm, the driver circuit 174 amplifies the PWM signal, and when driving the upper arm to the corresponding gate electrode of the IGBT 100 of the lower arm, the driver circuit 174 sets the level of the reference potential of the PWM signal. After shifting to the level of the reference potential of the upper arm, the PWM signal is amplified and output as a drive signal to the gate electrode of the corresponding IGBT 100 of the upper arm. Thereby, each IGBT100 performs switching operation based on the input drive signal.

  FIG. 3 is a block configuration diagram of the drive device of the IGBT 100 according to the present embodiment. In this figure, only the IGBT 100 to be driven is displayed, and the configuration related to the load connected to the IGBT 100, the turn-off control, and other IGBT devices are omitted.

  The driving apparatus of the present embodiment includes a driving circuit 200 and a driving circuit 300, a driving circuit 200, a resistor 400 and a resistor 410 that connect the driving circuit 300 and the gate of the IGBT 100, a gate power supply V, and each driving circuit. A control circuit unit 600 that controls the operation of the first, a voltage change rate detection circuit 700, and voltage detection circuits 800, 900, and 1000 that detect a voltage applied to the gate. There are three voltage detection circuits for one IGBT 100. This is because there are three reference voltages for the gate voltage described later. These voltage detection circuits 800, 900, and 1000 are built in the driver circuit 174. Further, the control circuit unit 600 and the drive circuits 200 and 300 are also built in the driver circuit 174.

  The control circuit unit 600 receives the on-gate input signal Vin, the voltage change rate detection circuit 700 and the output signals of the gate voltage detection circuits 800, 900, and 1000, and determines the timing for switching the drive circuits 200 and 300. Further, the control circuit unit 600 includes a logic circuit that switches between the drive circuit 200 and the drive circuit 300 in accordance with the timing. In the present embodiment, the drive circuits 200 and 300 are configured by pMOS transistors, but may be devices having other switch functions. The configuration of other circuit blocks may not be the same as the configuration described in this embodiment as long as it has the same function.

  FIG. 4 is a waveform showing the switching timing of the gate resistance according to the present embodiment. FIG. 4A is a waveform showing the switching timing of the gate resistance when the gate voltage in the mirror period (period 2) is smaller than a predetermined reference voltage (Vsp (2)). On the other hand, FIG. 4B is a waveform showing the switching timing of the gate resistance when the gate voltage in the mirror period (period 2) is larger than a predetermined reference voltage (Vsp (2)).

  As shown in FIG. 4A, when the gate voltage in the mirror period (period 2) is smaller than the reference voltage Vsp (2), the collector current becomes small (the collector current in period 2 from the latter half of period 2). Since the collector current is small, noise and the like are hardly generated. Therefore, when the possibility of noise generation is low, the gate resistance during the mirror period (period 2) is reduced in order to actively reduce the switching loss. Here, although it is required to detect the mirror period with high accuracy, in this embodiment, the voltage conversion rate detection circuit 700 detects the mirror period (period 2) which is a timing for switching the gate resistance. The gate voltage change rate (dV / dt value) is used.

  Specifically, the gate resistance switching timing according to the present embodiment will be described based on the waveform shown in FIG.

  First, when a Hi signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-on operation, and the gate voltage starts to rise (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage rises with time, and the gate voltage is detected by the voltage detection circuits 800, 900, and 1000. When the voltage detection circuit detects that the gate voltage has increased and reached a predetermined voltage Vsp (1) (t2), the control circuit unit 600 shuts off the drive circuit 300. Thereby, the power supply voltage V is applied to the IGBT gate through the resistor Ra connected to the drive circuit 200 (t2 to t3). The resistance value of the resistor Ra is set larger than the resistance value of the resistor Rb. This predetermined voltage Vsp (1) is determined by the characteristics of each IGBT, but is set to be smaller than at least the gate voltage value during the mirror period of the IGBT.

  Thereafter, the gate voltage detection circuit 900 detects the gate voltage and outputs a gate voltage waveform to the control circuit unit 600, and the control circuit unit 600 compares the detected gate voltage with a predetermined voltage Vsp (2).

  On the other hand, the gate voltage after the on-gate input signal Vin is input is input to the voltage change rate detection circuit 700, and the voltage change rate detection circuit 700 detects the change rate of the gate voltage. As described above, the mirror period, which is the gate resistance switching timing, is detected based on the gate voltage change rate. Specifically, when the gate voltage change rate (dV1) in the period (t1 to t2) in which the gate voltage starts to rise after entering the turn-on operation is 100%, for example, 30% of the gate voltage change rate (dV1). When the gate voltage change rate decreases to about% (dV2), it can be determined that it is the mirror period of the IGBT 100. In the determination of the mirror period, the decrease rate of the gate voltage change rate is determined by the characteristics of each IGBT, and a threshold value of the gate voltage change rate can be set according to the IGBT to be used.

  As described above, based on the gate voltage change rate, the mirror period which is the gate resistance switching timing is detected (t3), and when the gate voltage at that time is smaller than the predetermined voltage Vsp (2), the collector current Noise is less likely to occur because of the smaller. Therefore, in order to actively reduce the switching loss, the gate resistance during the mirror period (period 2) is reduced (t3).

  As a result, when the possibility of noise generation is low, it is possible to actively reduce the switching loss and suppress the heat generation of the entire drive device.

  On the other hand, as shown in FIG. 4B, when the gate voltage is larger than a predetermined reference voltage (Vsp (2)) as in the mirror period (period 2), the collector current increases (period 2 Current from second half to period 3). Since the collector current is large, there is a risk of malfunction and element destruction due to noise or the like. Therefore, when the possibility of noise generation is high, the gate resistance during the mirror period (period 2) is increased in order to positively suppress noise generation. As in the case of FIG. 4A, it is required to detect the mirror period with high accuracy. In this embodiment, in order to detect the mirror period (period 2) which is the timing for switching the gate resistance, The conversion rate detection circuit 700 uses the gate voltage change rate (dV / dt value).

  Specifically, the gate resistor switching timing according to the present embodiment will be described based on the waveform shown in FIG. Here, from the time when the on-gate input signal Vin is input (t1) to the time when the mirror period is reached, the description is similar to the description of FIG.

  At t3, the gate voltage detection circuit 900 detects the gate voltage and outputs a gate voltage waveform to the control circuit unit 600, and the control circuit unit 600 compares the detected gate voltage with a predetermined voltage Vsp (2).

  On the other hand, as described above, based on the gate voltage change rate, the mirror period which is the switching timing of the gate resistance is detected (t3), and when the gate voltage at that time is larger than the predetermined voltage Vsp (2), There is a high possibility that noise will occur because the collector current increases. Therefore, in order to positively suppress noise generation, the gate resistance value in the mirror period (period 2) is increased, that is, Ra is maintained (t3 to t4). Note that the gate resistance value may not only be maintained as Ra but also be larger than Ra. That is, the drive circuits 200 and 300 may be controlled so that the gate resistance value does not become smaller than Ra.

  As a result, when the possibility of noise generation is high, the possibility of malfunction and element destruction due to noise or the like is reduced even if a small amount of switching loss is sacrificed.

  In the embodiment described in FIG. 4, the gate resistance is decreased when the gate voltage is smaller than the reference voltage Vsp (2), and the gate resistance is increased when the gate voltage is larger than the reference voltage Vsp (2). The reverse relationship may be used. Depending on the characteristics of IBGT, noise may easily occur when the gate voltage is lower than the reference voltage Vsp (2). In this case, the gate resistance is increased in order to actively suppress noise generation. . Even in this case, since it is necessary to detect the mirror period with higher accuracy, the mirror period which is the switching timing of the gate resistance is detected based on the gate voltage change rate.

  FIG. 5 is a waveform showing the switching timing of the gate resistance when the voltage change rate detection circuit 700 fails to detect the change rate of the gate voltage. In this figure, the gate voltage change rate and gate resistance according to (A) show the case where the detection of the gate voltage change rate did not fail, and the gate voltage change rate and gate resistance according to (B) are: The case where the detection of the change rate of the gate voltage has failed is shown. Since Δt1 is a mirror period, the voltage change rate is small. Vg1 indicates a change in the gate voltage when the detection of the gate voltage change rate fails. Δt2 is a period in which the voltage change rate is small because it is a mirror period like Δt1, but it indicates that the mirror period of Δt1 is long due to a large gate resistance value, as will be described later.

  In the present embodiment, even if the voltage change rate detection circuit 700 fails to detect the gate voltage change rate, a measure is taken to reduce the possibility of malfunction due to noise or the like and element destruction.

  Specifically, when a Hi signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-on operation, and the gate voltage starts to rise (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage rises with time, and the gate voltage is detected by the voltage detection circuits 800, 900, and 1000. When the voltage detection circuit detects that the gate voltage has increased and has reached a predetermined voltage Vsp (1) (t2), the control circuit unit 600 first shuts off the drive circuit 300. As illustrated in FIG. 4, the predetermined voltage Vsp (1) is determined by the characteristics of each IGBT, but is set to be smaller than at least the gate voltage value during the mirror period of the IGBT.

  Thereafter, the voltage change rate detection circuit 700 detects the gate voltage change rate even though the change rate of the IGBT 100 is dV2 (mirror period from t3 to t6) as in the case of the gate voltage change rate detection failure according to (B). And the detection value of the voltage change rate detection circuit 700 is between dV1 and dV2, and the mirror period cannot be detected. If the gate resistance is changed from a large resistance value Ra to a small resistance value RaRb / (Ra + Rb) in such a state that the mirror period cannot be detected, the collector current may increase rapidly, and malfunctions due to noise or the like may occur. There is a risk of device destruction.

  Therefore, in the present embodiment, the gate resistance is first changed to a large resistance value Ra when the gate voltage reaches a predetermined voltage Vsp (1) (t2). Since the mirror period cannot be detected correctly until the voltage change rate detection circuit 700 detects dV2, the gate resistance is maintained at the large resistance value Ra. As a result, when there is a high possibility of noise generation, the possibility of malfunction and element destruction due to noise or the like is reduced even at the expense of a small switching loss, thereby improving reliability.

  After that, when the detection value of the voltage change rate detection circuit 700 detects dV1 again without detecting dV2, the gate resistance is changed from a large resistance value Ra to a small resistance value RaRb / (Ra + Rb). (T6). This prevents the gate resistance from remaining high for a long period of time, thereby reducing the switching loss.

  FIG. 6 is a waveform showing the switching timing of the gate resistance when the voltage change rate detection circuit 700 fails to detect the change rate of the gate voltage. In this figure, the gate voltage change rate and gate resistance according to (A) show the case where the detection of the gate voltage change rate did not fail, and the gate voltage change rate and gate resistance according to (B) are: The case where the detection of the change rate of the gate voltage has failed is shown. Since Δt1 is a mirror period, the voltage change rate is small. Vg1 indicates a change in the gate voltage when the detection of the gate voltage change rate fails. Δt2 is a period in which the voltage change rate is small because it is a mirror period like Δt1, but it indicates that the mirror period of Δt1 is long due to a large gate resistance value, as will be described later.

  In the present embodiment, even when the voltage change rate detection circuit 700 fails to detect the gate voltage change rate, it is possible to reduce the switching loss while reducing the possibility of malfunction due to noise or the like and element destruction. Take measures.

  Specifically, when a Hi signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-on operation, and the gate voltage starts to rise (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage rises with time, and the gate voltage is detected by the voltage detection circuits 800, 900, and 1000. When the voltage detection circuit detects that the gate voltage has increased and reached a predetermined voltage Vsp (1) (t2), the control circuit unit 600 shuts off the drive circuit 300.

  Here, it is assumed that the gate voltage becomes larger than a predetermined voltage Vsp (2) as shown in FIG. Therefore, in order to suppress noise generation, the gate resistance is maintained as the resistance Ra during the period from t3 to t4.

  On the other hand, when the actual gate voltage change rate of the IGBT 100 has changed to dV1 at t4, the detection value of the voltage change rate detection circuit 700 remains dV2 as shown in FIG. Cannot detect the end of the mirror period (t3 to t4) and cannot change the gate resistance. If the gate resistance Ra is kept large as it is, the switching loss increases.

  Therefore, when the voltage detection circuit 800, 900, 1000 detects that the gate voltage has reached Vsp (3) as in the case of the gate voltage change rate detection failure according to (B), Regardless of the detection, the gate resistance is changed from the large resistance value Ra to the small resistance value RaRb / (Ra + Rb) (t6). This prevents the gate resistance from maintaining a large resistance value Ra for a long period of time, thereby reducing the switching loss.

  FIG. 7 is a waveform showing the off timing of switching of the gate resistance according to the present embodiment. FIG. 7A is a waveform showing the switching timing of the gate resistance when the gate voltage in the mirror period (period 5) is smaller than a predetermined reference voltage (Vsp (2)). On the other hand, FIG. 7B is a waveform showing the switching timing of the gate resistance when the gate voltage in the mirror period (period 5) is larger than a predetermined reference voltage (Vsp (2)).

  As shown in FIG. 7A, when the gate voltage in the mirror period (period 5) is smaller than the reference voltage Vsp (2), the collector current becomes small (collector current in the period 5 to the period 6). Since the collector current is small, noise and the like are hardly generated. Therefore, when the possibility of noise generation is low, the gate resistance during the mirror period (period 5) is reduced in order to actively reduce the switching loss. Here, although it is required to detect the mirror period with high accuracy, in this embodiment, the voltage conversion rate detection circuit 700 detects the mirror period (period 5) which is a timing for switching the gate resistance. The gate voltage change rate (dV / dt value) is used.

  Specifically, the gate resistor switching timing according to the present embodiment will be described based on the waveform shown in FIG.

  First, when a Low signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-off operation, and the gate voltage starts to decrease (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage rises with time, and the gate voltage is detected by the voltage detection circuits 800, 900, and 1000. When the voltage detection circuit detects that the gate voltage has increased and reached a predetermined voltage Vsp (3) (t2), the control circuit unit 600 shuts off the drive circuit 300. Thereby, the power supply voltage V is applied to the IGBT gate through the resistor Ra connected to the drive circuit 200 (t2 to t3). The resistance value of the resistor Ra is set larger than the resistance value of the resistor Rb. The predetermined voltage Vsp (3) is determined by the characteristics of each IGBT, but is set to be larger than at least the gate voltage value during the mirror period of the IGBT.

  Thereafter, the gate voltage detection circuit 900 detects the gate voltage and outputs a gate voltage waveform to the control circuit unit 600, and the control circuit unit 600 compares the detected gate voltage with a predetermined voltage Vsp (2).

  On the other hand, the gate voltage after the on-gate input signal Vin is input is input to the voltage change rate detection circuit 700, and the voltage change rate detection circuit 700 detects the change rate of the gate voltage. As described above, the mirror period, which is the gate resistance switching timing, is detected based on the gate voltage change rate. More specifically, when the gate voltage change rate (dV1) in the period (t1 to t2) in which the gate voltage starts to fall after entering the turn-off operation is 100%, for example, the gate voltage change rate (dV1) is 30%. When the gate voltage change rate decreases to about% (dV2), it can be determined that it is the mirror period of the IGBT 100. In the determination of the mirror period, the decrease rate of the gate voltage change rate is determined by the characteristics of each IGBT, and a threshold value of the gate voltage change rate can be set according to the IGBT to be used.

  As described above, based on the gate voltage change rate, the mirror period which is the gate resistance switching timing is detected (t3), and when the gate voltage at that time is smaller than the predetermined voltage Vsp (2), the collector current Noise is less likely to occur because of the smaller. Therefore, in order to actively reduce the switching loss, the gate resistance during the mirror period (period 2) is reduced (t3).

  As a result, when the possibility of noise generation is low, it is possible to actively reduce the switching loss and suppress the heat generation of the entire drive device.

  On the other hand, as shown in FIG. 7B, when the gate voltage is larger than a predetermined reference voltage (Vsp (2)) as in the mirror period (period 5), the collector current increases (period 5 from the second half to the current in period 6). Since the collector current is large, there is a risk of malfunction and element destruction due to noise or the like. Therefore, when the possibility of noise generation is high, the gate resistance during the mirror period (period 2) is increased in order to positively suppress noise generation. As in the case of FIG. 7A, it is required to accurately detect the mirror period. In the present embodiment, in order to detect the mirror period (period 5) that is the timing for switching the gate resistance, The conversion rate detection circuit 700 uses the gate voltage change rate (dV / dt value).

  Specifically, the gate resistor switching timing according to the present embodiment will be described based on the waveform shown in FIG. Here, from the time when the on-gate input signal Vin is input (t1) to the time when the mirror period is reached, the description is similar to the description of FIG.

  At t3, the gate voltage detection circuit 900 detects the gate voltage and outputs a gate voltage waveform to the control circuit unit 600, and the control circuit unit 600 compares the detected gate voltage with a predetermined voltage Vsp (2).

  On the other hand, as described above, based on the gate voltage change rate, the mirror period which is the switching timing of the gate resistance is detected (t3), and when the gate voltage at that time is larger than the predetermined voltage Vsp (2), There is a high possibility that noise will occur because the collector current increases. Therefore, in order to positively suppress noise generation, the gate resistance value in the mirror period (period 5) is increased, that is, Ra is maintained (t3 to t4).

  As a result, when the possibility of noise generation is high, the possibility of malfunction and element destruction due to noise or the like is reduced even if a small amount of switching loss is sacrificed.

  In the embodiment described in FIG. 7, the gate resistance is decreased when the gate voltage is smaller than the reference voltage Vsp (2), and the gate resistance is increased when the gate voltage is larger than the reference voltage Vsp (2). The reverse relationship may be used. Depending on the characteristics of IBGT, noise may easily occur when the gate voltage is lower than the reference voltage Vsp (2). In this case, the gate resistance is increased in order to actively suppress noise generation. . Even in this case, since it is necessary to detect the mirror period with higher accuracy, the mirror period which is the switching timing of the gate resistance is detected based on the gate voltage change rate.

  FIG. 8 is a waveform showing the switching timing of the gate resistance when the voltage change rate detection circuit 700 fails to detect the change rate of the gate voltage. In this figure, the gate voltage change rate and gate resistance according to (A) show the case where the detection of the gate voltage change rate did not fail, and the gate voltage change rate and gate resistance according to (B) are: The case where the detection of the change rate of the gate voltage has failed is shown. The same reference numerals as those in FIG. 5 are used in the same manner as in FIG.

  In the present embodiment, even if the voltage change rate detection circuit 700 fails to detect the gate voltage change rate, a measure is taken to reduce the possibility of malfunction due to noise or the like and element destruction.

  Specifically, when a Low signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-on operation, and the gate voltage starts to rise (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage decreases with time, and the voltage detection circuits 800, 900, and 1000 detect this gate voltage. When the voltage detection circuit detects that the gate voltage has dropped and reached a predetermined voltage Vsp (3) (t2), the control circuit unit 600 first shuts off the drive circuit 300. As illustrated in FIG. 7, the predetermined voltage Vsp (3) is determined by the characteristics of each IGBT, but is set to be smaller than at least the gate voltage value during the mirror period of the IGBT.

  Thereafter, the voltage change rate detection circuit 700 detects the gate voltage change rate even though the change rate of the IGBT 100 is dV2 (mirror period from t3 to t6) as in the case of the gate voltage change rate detection failure according to (B). And the detection value of the voltage change rate detection circuit 700 is between dV1 and dV2, and the mirror period cannot be detected. If the gate resistance is changed from a large resistance value Ra to a small resistance value RaRb / (Ra + Rb) in such a state that the mirror period cannot be detected, the collector current may increase rapidly, and malfunctions due to noise or the like may occur. There is a risk of device destruction.

  Therefore, in the present embodiment, the gate resistance is first changed to a large resistance value Ra when the gate voltage reaches a predetermined voltage Vsp (3) (t2). Since the mirror period cannot be detected correctly until the voltage change rate detection circuit 700 detects dV2, the gate resistance is maintained at the large resistance value Ra. As a result, when there is a high possibility of noise generation, the possibility of malfunctions and element destruction due to noise or the like is reduced even if a small amount of switching loss is sacrificed, thereby improving reliability.

  After that, when the detection value of the voltage change rate detection circuit 700 detects dV1 again without detecting dV2, the gate resistance is changed from a large resistance value Ra to a small resistance value RaRb / (Ra + Rb). (T6). This prevents the gate resistance from remaining high for a long period of time, thereby reducing the switching loss.

  FIG. 9 is a waveform showing the switching timing of the gate resistance when the voltage change rate detection circuit 700 fails to detect the change rate of the gate voltage. In this figure, the gate voltage change rate and gate resistance according to (A) show the case where the detection of the gate voltage change rate did not fail, and the gate voltage change rate and gate resistance according to (B) are: The case where the detection of the change rate of the gate voltage has failed is shown. What uses the same reference numerals as those in FIG. 6 is the same as the description in FIG.

  In the present embodiment, even when the voltage change rate detection circuit 700 fails to detect the gate voltage change rate, it is possible to reduce the switching loss while reducing the possibility of malfunction due to noise or the like and element destruction. Take measures.

  Specifically, when a Low signal is input to the on-gate input signal Vin (t1), the IGBT 100 enters a turn-off operation, and the gate voltage starts to decrease (t1 to t2). At this time, the drive circuit 200 and the drive circuit 300 are conductive, and the power supply voltage V is applied to the IGBT gate via RaRb / (Ra + Rb), which is a resistance value lower than the resistance Ra (t1 to t2).

  The gate voltage rises with time, and the gate voltage is detected by the voltage detection circuits 800, 900, and 1000. When the voltage detection circuit detects that the gate voltage has dropped and reached a predetermined voltage Vsp (3) (t2), the control circuit unit 600 shuts off the drive circuit 300.

  Here, it is assumed that the gate voltage becomes higher than a predetermined voltage Vsp (2) as shown in FIG. Therefore, in order to suppress noise generation, the gate resistance is maintained as the resistance Ra during the period from t3 to t4.

  On the other hand, when the actual gate voltage change rate of the IGBT 100 has changed to dV1 at t4, the detection value of the voltage change rate detection circuit 700 remains dV2 as shown in FIG. Cannot detect the end of the mirror period (t3 to t4) and cannot change the gate resistance. If the gate resistance Ra is kept large as it is, the switching loss increases.

  Therefore, when the voltage detection circuits 800, 900, and 1000 detect that the gate voltage has reached Vsp (1) as in the case of the gate voltage change rate detection failure according to (B), Regardless of the detection, the gate resistance is changed from the large resistance value Ra to the small resistance value RaRb / (Ra + Rb) (t6). This prevents the gate resistance from maintaining a large resistance value Ra for a long period of time, thereby reducing the switching loss.

  FIG. 10 is a perspective view in which the entire configuration of the power conversion device according to the embodiment of the present invention is disassembled into components.

  As shown in FIG. 10, a cooling water channel 19 is provided in the middle of the housing 12, and two sets of openings are formed in the upper part of the cooling water channel 19 side by side in the flow direction. Two inverter devices 142 are fixed to the upper surface of the cooling water channel 19 so that the two sets of openings are respectively closed by the inverter devices 142. Each inverter device 142 is provided with a fin for heat dissipation, and the fin of each inverter device 142 protrudes from the opening of the cooling water passage 19 into the flow of cooling water.

  An opening 404 for facilitating aluminum casting is formed below the cooling water channel 19, and the opening is closed by a cover 420. An auxiliary inverter device 43 is attached to the lower side of the cooling water passage 19. The inverter device 43 for auxiliary machinery has a circuit similar to the inverter circuit 144 built therein, and has an inverter circuit having a built-in power semiconductor element constituting the inverter circuit 144. The auxiliary inverter device 43 is fixed to the lower surface of the cooling water passage 19 such that the heat dissipating metal surface of the built-in inverter circuit faces the lower surface of the cooling water passage 19.

  In addition, a lower case 16 is provided in the lower part of the cooling water flow path 19 so as to dissipate heat. It is fixed to the surface of the lower case 16 so as to face the surface. With this structure, cooling can be efficiently performed using the upper surface and the lower surface of the cooling water channel 19, which leads to downsizing of the entire power conversion device.

  When the cooling water from the inlet / outlet pipes 13 and 14 flows through the cooling water flow path 19, the heat dissipating fins of the two inverter devices 142 provided together are cooled, and the entire two inverter devices 142 are cooled. . The auxiliary inverter device 43 provided on the lower surface of the cooling water passage 19 is also cooled at the same time.

  Further, the casing 12 provided with the cooling water flow path 19 is cooled, whereby the lower case 16 provided at the lower portion of the casing 12 is cooled, and by this cooling, the heat of the capacitor module 500 is transferred to the lower case 16 and the casing. The capacitor module 500 is cooled by being thermally conducted to the cooling water through the body 12.

  A control circuit board 20 and a drive circuit board 22 are disposed above the inverter device 142, a driver circuit 174 is mounted on the drive circuit board 22, and a control circuit 172 having a CPU is mounted on the control circuit board 20. . Further, a metal base plate 11 is disposed between the drive circuit board 22 and the control circuit board 20, and the metal base plate 11 functions as an electromagnetic shield for a circuit group mounted on both the boards 22 and 20, and also the drive circuit board. The heat generated by the control circuit board 20 and the control circuit board 20 is released and cooled. In this way, the cooling water channel 19 is provided in the central portion of the housing 19, the inverter device 142 for driving the vehicle is arranged on one side thereof, and the inverter device 43 for auxiliary machines is arranged on the other side. Thus, cooling can be efficiently performed in a small space, and the entire power conversion device can be downsized. Further, by making the main structure of the cooling water channel 19 at the center of the casing by casting an aluminum material integrally with the casing 12, the cooling water channel 19 has the effect of increasing the mechanical strength in addition to the cooling effect. Further, by making the aluminum casting, the housing 12 and the cooling water flow path 19 are integrated with each other, heat conduction is improved, and cooling efficiency is improved.

  The drive circuit board 22 is provided with an inter-board connector 23 that passes through the metal base plate 11 and is connected to a circuit group of the control circuit board 20. The control circuit board 20 is provided with a connector 21 for electrical connection with the outside. The connector 21 transmits a signal to, for example, a lithium battery module mounted on the vehicle as the battery 136, for example, outside the power conversion device, and a signal indicating the state of the battery from the lithium battery module or a charging state of the lithium battery. A signal is sent. The inter-board connector 23 is provided in order to exchange signals with the control circuit 172 held on the control circuit board 20, and a signal line 176 is provided although not shown. The inverter circuit switching timing signal is transmitted from the control circuit board 20 to the drive circuit board 22 through the connector 176 and the board-to-board connector 23, and the drive circuit board 22 generates a gate drive signal which is a drive signal. Applied to each electrode.

  Openings are formed in the upper part and the lower part of the housing 12, and these openings are closed by fixing the upper case 10 and the lower case 16 to the housing 12 with, for example, screws. A cooling water channel 19 is provided in the center of the housing 12, and the inverter device 142 and the cover 420 are fixed to the cooling water channel 19. In this way, the cooling water channel 19 is completed, and a water leak test of the water channel is performed. When the water leakage test is passed, the operation of attaching the substrate and the capacitor module 500 from the upper and lower openings of the housing 12 can be performed next. In this way, the cooling water flow path 19 is arranged in the center, and then the work for fixing the necessary parts from the upper and lower openings of the housing 12 can be performed, thereby improving the productivity. Moreover, it becomes possible to complete the cooling water flow path 19 first and to attach other parts after the water leak test, which improves both productivity and reliability.

It is a figure which shows the control block of a hybrid electric vehicle. It is explanatory drawing of the electric circuit structure of the inverter circuit part 140 and the inverter apparatus 142. FIG. It is a block block diagram of the drive device of IGBT100 which concerns on this embodiment. It is a wave form diagram which shows the switching timing of the gate resistance which concerns on this embodiment (at the time of turn-on). It is a wave form diagram which shows the switching timing of the gate resistance when the detection of the change rate of the gate voltage according to the present embodiment has failed (when turned on). It is a wave form diagram which shows the switching timing of the gate resistance when the detection of the change rate of the gate voltage according to the present embodiment has failed (when turned on). It is a wave form diagram which shows the switching timing of the gate resistance which concerns on this embodiment (at the time of turn-off). It is a wave form diagram which shows the switching timing of the gate resistance when the detection of the rate of change of the gate voltage according to the present embodiment fails (at the time of turn-off). It is a wave form diagram which shows the switching timing of the gate resistance when the detection of the rate of change of the gate voltage according to the present embodiment fails (at the time of turn-off). It is the perspective view which decomposed | disassembled the whole structure of the power converter device which concerns on embodiment of this invention into each component.

Explanation of symbols

1 Power converters 43, 142 Inverter device 100 IGBT (insulated gate bipolar transistor)
110 hybrid electric vehicle 112 front wheel 114 front wheel axle 116 front wheel side differential gear 112 transmission 120 engine 122 power distribution mechanism 136 battery 140 inverter circuit unit 150 upper and lower arm series circuit 156 diode 170 control unit 172 control circuit 174 driver circuit 176 signal line 192 194 Motor generator 200, 300 Drive circuit 400, 410 Resistance 500 Capacitor module 600 Control circuit unit 700 Voltage change rate detection circuit 800, 900, 1000 Voltage detection circuit Vin On-gate input signal

Claims (4)

A voltage-driven switching device drive device,
A drive circuit unit electrically connected to the gate electrode of the switching element and applying a gate voltage to the gate electrode;
A voltage detector for detecting a gate voltage applied to the gate electrode;
A voltage change rate detector that detects a change rate of the gate voltage applied to the gate electrode;
The drive circuit unit is controlled based on the detection result of the voltage detection unit and the detection result of the voltage change rate detection unit, and the drive circuit unit is controlled to change the gate voltage applied to the gate electrode. A control circuit unit;
A plurality of gate resistance means electrically connected between the drive circuit section and the gate electrode of the switching element,
The control circuit unit is
The gate detected by the voltage detection unit after receiving a gate-on signal for switching the main current energizing the switching element from a non-energized state to a conductive state or a gate-off signal for switching the main current from the energized state to the non-energized state The voltage of the gate resistance means is compared with a predetermined first reference voltage, and based on the comparison result, the electrical resistance of the gate resistance means is such that the effective gate resistance value becomes a first effective gate resistance value that is larger than that before receiving the gate-on signal. Change the connection status,
After changing the connection state of the gate resistance means, based on a comparison result between the gate voltage and a second reference voltage higher than the first reference voltage and a detection result of the voltage change rate detection unit, A switching element driving device including a determination unit that determines whether or not to change the connection state . The switching element drive device according to claim 1 ,
The determination unit determines the effective gate resistance value as the first effective gate resistance value when the gate voltage is smaller than the second reference voltage and the detection result of the voltage change rate detection unit is smaller than a predetermined voltage change rate. A switching element driving device that determines to change the electrical connection state of the gate resistance means so as to be smaller, and the control circuit unit controls the driving circuit based on the determination result. The switching element drive device according to claim 1 ,
The determination unit determines the effective gate resistance value as the first effective gate resistance value when the gate voltage is greater than the second reference voltage and the detection result of the voltage change rate detection unit is smaller than a predetermined voltage change rate. A switching element driving device that determines to change to an electrical connection state of the gate resistance means so as to be maintained or increased, and the control circuit unit controls the driving circuit based on the determination result. A vehicle inverter device comprising the switching element drive device according to any one of claims 1 to 3 ,
The switching element is an IGBT;
A vehicle inverter device comprising an inverter circuit configured by connecting a plurality of upper and lower arms connected in series with the IGBTs in parallel.

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