JP2018033259A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of fears of an excessive surge voltage being generated at a main terminal of a power semiconductor element in the case of intercepting large main current.SOLUTION: When an overcurrent detection circuit 108 detects main current flowing through an IGBT 101 being overcurrent, a third switching element 113 is turned on by a control signal from a control circuit 150 receiving a signal from the overcurrent detection circuit 108. In this case, the control signal from the control circuit 150 is not input to a second switching element 112, making the second switching element 112 be off. When the third switching element 113 is turned on, a gate capacitor 103 of the IGBT 101 is made to discharge electricity via a saturation current circuit 114 at speed lower than that in the case where the second switching element 112 is turned on.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power conversion device.

  In a hybrid vehicle or an electric vehicle, a power converter is used to drive a motor. The power converter is configured by an inverter circuit using a power semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). And a power converter device is calculated | required in size reduction, a loss reduction, and high reliability.

  Patent Document 1 discloses a circuit that enables high-speed operation of a power semiconductor element by disposing an inductor around a path through which a main current of the power semiconductor element flows, and connecting the inductor to the gate of the power semiconductor element. ing.

JP 2008-235997 A

  In the circuit described in Patent Document 1 described above, when a large main current is interrupted, the coupling inductor formed between the main current path and the control current path increases the speed at which the gate voltage of the power semiconductor element decreases. Thus, an excessive surge voltage may be generated in the power semiconductor element.

  The power conversion device according to the present invention is provided in a path of a power semiconductor element that is on / off controlled by a gate drive circuit and a control current that turns off the power semiconductor element, and limits the control current to a predetermined saturation current and And a saturation current circuit for turning off the power semiconductor element.

  According to the present invention, the surge voltage of the power semiconductor element can be reduced.

It is a figure which shows the system configuration | structure of a motor vehicle. It is a figure which shows the circuit structure of a power converter device. It is a circuit diagram which shows the principal part of the power converter device which concerns on 1st Embodiment. It is a time chart of a gate drive circuit and IGBT. It is a figure which shows the voltage-current characteristic of a saturation current circuit. It is a figure which shows the external appearance of a power semiconductor module. It is a figure which shows the mounting structure of a power converter device. It is a figure which shows the external appearance of the power semiconductor module for an up-and-down arm. It is a circuit diagram which shows the coupling inductor of a power converter device. It is a circuit diagram which shows the coupling inductor of a power converter device. It is a circuit diagram which shows the coupling inductor of a power converter device. It is a circuit diagram which shows the principal part of a power converter device. It is a circuit diagram which shows the principal part of a power converter device. It is a graph which shows the surge voltage of IGBT. It is a circuit diagram which shows the principal part of the power converter device which concerns on 2nd Embodiment. It is a circuit diagram which shows the principal part of the power converter device which concerns on 3rd Embodiment.

(First embodiment)
A power converter according to the present embodiment will be described with reference to the drawings. The power conversion device according to the present embodiment can be applied to a hybrid vehicle or an electric vehicle. As an example, a case where the power conversion device is applied to a hybrid vehicle will be described.

  FIG. 1 is a diagram showing a system configuration of a hybrid vehicle. The internal combustion engine EGN and the motor generator MG are power sources that generate driving torque for the automobile. Motor generator MG not only generates rotational torque but also has a function of converting mechanical energy (rotational force) applied to motor generator MG into electric power. The motor generator MG is, for example, a synchronous motor / generator or an induction motor / generator, and operates as a motor or a generator depending on the driving method of the automobile.

  The output side of the internal combustion engine EGN is transmitted to the motor generator MG via the power distribution mechanism TSM, and the rotation torque from the power distribution mechanism TSM or the rotation torque generated by the motor generator MG is transmitted to the wheels via the transmission TM and the differential gear DEF. It is transmitted to WH.

  On the other hand, during regenerative braking operation, rotational torque is transmitted from wheel WH to motor generator MG, and motor generator MG generates AC power based on the transmitted rotational torque. The generated AC power is converted into DC power by the power conversion device 251 to charge the battery 901 for high voltage, and the charged power is used again as travel energy.

  The power conversion device 251 includes an inverter circuit 902 and a smoothing capacitor 255. The inverter circuit 902 is electrically connected to the battery 901 through the smoothing capacitor 255, and power is exchanged between the battery 901 and the inverter circuit 902. The smoothing capacitor 255 smoothes the DC power supplied to the inverter circuit 902.

  The control circuit 150 of the power conversion device 251 receives a command from the host control device via the communication connector 903, or transmits data representing the state to the host control device. Control circuit 150 calculates a control amount of motor generator MG based on the input command, generates a control signal based on the calculation result, and supplies the control signal to gate drive circuit 110. Based on this control signal, the gate drive circuit 110 generates a drive signal for controlling the inverter circuit 902.

  When motor generator MG is operated as an electric motor, inverter circuit 902 generates AC power based on the DC power supplied from battery 901 and supplies it to motor generator MG. The configuration composed of motor generator MG and inverter circuit 902 operates as an electric / power generation unit.

FIG. 2 is a diagram illustrating a circuit configuration of the power conversion device 251. In the following description, an example in which an IGBT (Insulated Gate Bipolar Transistor) is used as a power semiconductor element will be described.
The power conversion device 251 includes an upper arm and a lower arm each including the IGBT 101 and the diode 102 corresponding to three phases including a U phase, a V phase, and a W phase of AC power. These three-phase upper and lower arms constitute an inverter circuit 902.

  The collector electrode of the IGBT 101 of the upper arm is electrically connected to the capacitor terminal on the positive side of the smoothing capacitor 255, and the emitter electrode of the IGBT 101 of the lower arm is electrically connected to the capacitor terminal on the negative side of the smoothing capacitor 255.

  The IGBT 101 includes a collector electrode, an emitter electrode, and a gate electrode. A diode 102 is electrically connected between the collector electrode and the emitter electrode. Note that a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) may be used as the power semiconductor element, and in this case, the diode 102 is unnecessary. As a power semiconductor element, IGBT is suitable when the DC voltage is relatively high, and MOSFET is suitable when the DC voltage is relatively low.

  The gate drive circuit 110 is provided between the emitter electrode of the IGBT 101 and the gate electrode, and controls the IGBT 101 on and off. The control circuit 150 supplies a control signal to the gate driving circuit 110.

  The IGBT 101 includes a current detection emitter electrode, and the output of the current detection emitter electrode is input to the overcurrent detection circuit 108. When the overcurrent detection circuit 108 detects an overcurrent in which the main current flowing through the inverter circuit 902 having the upper and lower arms configured by the IGBT 101 exceeds a predetermined current, the overcurrent detection circuit 108 notifies the control circuit 150 of this. Upon receiving this notification, the control circuit 150 causes a later-described saturation current circuit in the gate drive circuit 110 to function. The saturation current circuit limits the control current flowing to the gate electrode of the IGBT 101 to a predetermined saturation current. There are various methods for detecting the overcurrent flowing through the IGBT 101, and the present invention is not limited to this embodiment.

  As described above, the control circuit 150 receives a control command from the host control device, generates a control signal for controlling the IGBT 101 that constitutes the upper arm or the lower arm of the inverter circuit 902 based on the control command, and sends it to the gate drive circuit 110. Supply. Based on the control signal, the gate drive circuit 110 supplies a drive signal for driving the IGBT 101 constituting the upper arm or the lower arm of each phase to the IGBT 101 of each phase.

  The IGBT 101 performs an on or off operation based on a drive signal from the gate drive circuit 110, converts the DC power supplied from the battery 901 into three-phase AC power, and the converted power is supplied to the motor generator MG. .

(First embodiment)
FIG. 3 is a circuit diagram showing a main part of the power conversion device 251 according to the first embodiment of the present invention. The current detection emitter electrode and the overcurrent detection circuit 108 provided in the IGBT 101 are not shown.

  The IGBT 101 is ON / OFF controlled by the gate drive circuit 110 charging / discharging the gate capacitance 103. The collector wiring 104 and the auxiliary emitter wiring 105 of the IGBT 101 constitute a coupled inductor. The gate driving circuit 110 includes first to third switching elements 111, 112, 113, a saturation current circuit 114, gate resistors 115, 116, and a gate power source 117.

  The first switching element 111 is connected between the gate power supply 117 and the gate resistor 115, and is connected to the gate terminal of the IGBT 101 through the gate resistor 115. When the first switching element 111 is turned on by a control signal from the control circuit 150, the gate capacitance 103 of the IGBT 101 is charged from the gate power supply 117 via the gate resistor 115. As a result, the IGBT 101 is controlled to be on.

  The second switching element 112 is connected between the ground potential 118 and the gate resistor 116, and is connected to the gate terminal of the IGBT 101 via the gate resistor 116. When the second switching element 112 is turned on by a control signal from the control circuit 150, the gate capacitance 103 of the IGBT 101 is discharged through the gate resistance 116. As a result, the IGBT 101 is controlled to be off. In a normal state in which the overcurrent detection circuit 108 (see FIG. 2) does not detect that the main current flowing through the IGBT 101 is an overcurrent, the first switching element 111 and the second switching element 112 perform on / off control of the IGBT 101.

  One of the third switching elements 113 is connected to the ground potential 118, and the other is connected to the gate terminal of the IGBT 101 via the saturation current circuit 114. The saturation current circuit 114 is a circuit in which the gate and source of an N-channel JFET (Junction Field Effect Transistor) are connected. When the overcurrent detection circuit 108 detects that the main current flowing through the IGBT 101 is an overcurrent, the third switching element 113 is turned on by a control signal from the control circuit 150 that receives a signal from the overcurrent detection circuit 108. To do. In this case, the control signal from the control circuit 150 is not input to the second switching element 112, and the second switching element 112 is off. When the third switching element 113 is turned on, the gate capacitance 103 of the IGBT 101 is discharged through the saturation current circuit 114 at a slower rate than when the second switching element 112 is turned on. That is, the saturation current circuit 114 is provided in a control current path for turning off the IGBT 101, limits the control current to a predetermined saturation current, and turns off the IGBT 101. In other words, the saturation current circuit 114 suppresses the rate at which the gate voltage of the IGBT 101 decreases when turning off the IGBT 101.

FIG. 4 is a time chart of the gate drive circuit 110 and the IGBT 101 when an overcurrent is detected by the overcurrent detection circuit 108.
In FIG. 4, Q ₁ indicates the on / off timing of the first switching element 111, Q ₂ indicates the on / off timing of the second switching element 112, and Q ₃ indicates the on / off timing of the third switching element 113. Indicates. Further, V _GE indicates the gate voltage of the IGBT 101, and i _G indicates the gate current of the IGBT 101. In FIG. 4, a solid line is a time chart in the power converter device 251 according to the present embodiment shown in FIG. In FIG. 4, a broken line is a comparative example, and shows a case where a resistance element is used instead of the saturation current circuit 114 of FIG. 3, for example.

  The overcurrent of the IGBT 101 refers to a current that exceeds the collector current range that is normally used. When the overcurrent is detected and the IGBT 101 is turned off, the switching speed is reduced so that the surge voltage between the collector and the emitter of the IGBT 101 does not become excessive. Causes of overcurrent include arm short circuit due to breakdown or malfunction of IGBT 101 or diode 102, output short circuit due to load breakdown, and the like.

With reference to FIG. 4, the operation of each switching element 111 to 113 and the change in gate voltage V _GE and gate current i _G will be described based on the passage of time (t _{0 to} t ₂ , t ₂ ′).
At time t ₀ , the overcurrent of the IGBT 101 is detected by the overcurrent detection circuit 108, and the first switching element 111 (Q ₁ ) is turned off by the control signal from the control circuit 150 that receives the signal from the overcurrent detection circuit 108. Then, the third switching element 113 (Q ₃ ) is turned on. The second switching element 112 (Q ₂ ) remains off. The gate capacitance 103 of the IGBT 101 is discharged through a path including the third switching element 113 (Q ₃ ), and the gate voltage V _{GE of the} IGBT 101 decreases with a time constant determined by the resistance in the current path of the gate capacitance 103 and the gate current i _G. Beginning, the IGBT 101 remains on until the gate voltage V _GE falls below the threshold voltage V _TH of the IGBT 101.

At time _{t 1,} the gate voltage _{V GE} of IGBT101 is lower than the threshold voltage _{V TH,} the collector current of IGBT101 begins to decrease. Depending on the speed of decrease of the collector current of IGBT101, the discharge current of the gate capacitance 103 of IGBT101 Coupled inductors by the collector wiring 104 and the auxiliary emitter wiring 105 (the negative direction of the gate current _{i G)} is increased.

In the power conversion device of the comparative example, as shown by the broken line in FIG. 4, the increase in the negative direction of the gate current i _G increases from time t ₁ to time t ₂ when the gate voltage V _{GE of the} IGBT 101 becomes 0. As a result, the gate voltage _VGE decreases sharply. For this reason, the rate of decrease in the collector current of the IGBT 101 becomes steep, and the surge voltage applied between the collector and the emitter of the IGBT 101 may become excessive.

In the power conversion apparatus 251 according to the present embodiment, an increase in the discharge direction of the gate current _{i G} between the time _{t 2} 'of the gate voltage _{V GE} from the time _{t 1} IGBT 101 becomes 0, the saturation current of the saturation current circuit 114 It is clamped by the value _{I SAT,} to prevent a steep drop in the gate voltage _{V GE.} Therefore, as compared with the comparative example, the rate of decrease in the collector current of the IGBT 101 becomes moderate, and the surge voltage applied between the collector and the emitter of the IGBT 101 is suppressed. That is, when the IGBT 101 is turned off, the saturation current circuit 114 suppresses the acceleration of the decrease in the gate voltage of the IGBT 101 due to the coupled inductor formed between the main current path flowing through the inverter circuit and the control current path. Thus, according to this embodiment, since the switching speed of IGBT101 can be suppressed, a surge voltage can be suppressed.

FIG. 5 is a diagram illustrating the voltage-current characteristics of the saturation current circuit 114. The saturation current value _ISAT is a current value at the threshold voltage _VTH . A desirable characteristic for the saturation current circuit 114 is to provide a boundary between the linear region and the saturation region at a voltage value equal to or lower than the threshold voltage V _TH , and as shown in FIG. The current value in the discharge direction is limited to the saturation current value I _SAT to suppress a rapid drop in the gate voltage V _GE . Further, when V _b is a voltage value three times the threshold voltage V _TH and I _b is a current value at V _b, the saturation current is such that I _b is 1.2 times or less of the saturation current value I _SAT. By using the circuit 114, the surge voltage is effectively suppressed.

  FIG. 6 is a view showing the appearance of the power semiconductor module 201. A power semiconductor module 201 shown in FIG. 6 includes an IGBT 101 and a diode 102, and includes a collector terminal 202, an emitter terminal 203, a gate terminal 211, an auxiliary emitter terminal 212, a current detection terminal 213, and temperature detection terminals 214 and 215. ing.

  In FIG. 6, since the collector terminal 202 and the auxiliary emitter terminal 212 are close to each other, a coupled inductor is formed without using a magnetic material. If the collector terminal 202 and the auxiliary emitter terminal 212 are brought closer to each other in order to reduce the size of the power converter 251, the coupling coefficient that is the degree of coupling of the coupled inductor increases, and the influence on the switching speed of the IGBT 101 increases. Therefore, in the power conversion device 251 according to the present embodiment, the surge voltage can be suppressed by the saturation current circuit 114 in the gate drive circuit 110 when the collector overcurrent of the IGBT 101 is cut off.

  FIG. 7 is a diagram showing a mounting structure of the power conversion device 251 using the power semiconductor module 201 of FIG. The power conversion device 251 includes housings 252, 253, 254, a power semiconductor module 201, a smoothing capacitor 255, a bus bar 256, a circuit board 257, and a flow path 258. The power semiconductor module 201 is cooled by the refrigerant flowing through the flow path 258. A gate drive circuit 110 and a control circuit 150 are mounted on the circuit board 257. The collector terminal 202 and the emitter terminal 203 of the power semiconductor module 201 are connected to the bus bar 256 by welding or soldering, and the gate terminal 211, the auxiliary emitter terminal 212, and the current detection terminal 213 of the power semiconductor module 201 are connected to the circuit board 257. The temperature detection terminals 214 and 215 are connected by soldering.

  FIG. 8 is a view showing an appearance of a power semiconductor module 501 incorporating power semiconductor elements for upper and lower arms. A power semiconductor module 501 shown in FIG. 8 includes a P terminal 502, an N terminal 503, an AC terminal 504, a gate terminal 511 of an upper arm power semiconductor element, an auxiliary emitter terminal 512, a current detection terminal 513, and a power semiconductor element of a lower arm. A gate terminal 521, an auxiliary emitter terminal 522, a current detection terminal 523, and temperature detection terminals 524 and 525 are provided. The P terminal 502 is a collector terminal of the upper arm, the N terminal 503 is an emitter terminal of the lower arm, and the AC terminal 504 is a connection portion between the upper arm and the lower arm. In FIG. 8, the P inductor 502 and the auxiliary emitter terminal 512 are close to each other to form a coupled inductor.

  9 to 11 are circuit diagrams showing the main parts of the power conversion device 251 having different coupling inductors. Although FIG. 3 shows the coupled inductor of the IGBT 101 collector and auxiliary emitter, other locations may constitute the coupled inductor.

  FIG. 9 is a circuit diagram showing a main part of the power converter 251 having a coupled inductor by the collector 104 and the gate 106 of the IGBT 101, and FIG. 10 shows the power converter 251 having a coupled inductor by the emitter 107 and the auxiliary emitter 105 of the IGBT 101. FIG. 11 is a circuit diagram showing a main part of a power conversion device 251 having a coupled inductor formed by the emitter 107 and the gate 106 of the IGBT 101. 9 to 11, the surge current between the collector and the emitter of the IGBT 101 can be suppressed by the saturation current circuit 114 in the gate drive circuit 110.

12 and 13 are circuit diagrams showing the main part of the power converter 251. FIG. As shown in these drawings, a resistance element or a capacitance element may be added to the saturation current circuit 114.
FIG. 12 shows an example in which a resistance element 121 is connected in series to the JFET of the saturation current circuit 114. FIG. 13 shows an example in which the capacitive element 122 is connected in parallel to the series circuit of the third switching element 113 and the saturation current circuit 114. In the circuit diagram shown in FIG. 13, the substantial gate capacitance can be increased. 12 and 13, the surge voltage between the collector and the emitter of the IGBT 101 can be suppressed by the saturation current circuit 114 in the gate drive circuit 110.

FIG. 14 is a graph showing a surge voltage between the collector and the emitter of the IGBT 101. In FIG. 14, the vertical axis represents the collector-emitter voltage, and the horizontal axis represents time.
The graph shown by the solid line in FIG. 14 is a simulation waveform when the overcurrent of the IGBT 101 is cut off in the power conversion device 251 according to this embodiment using the saturation current circuit 114 shown in FIG. On the other hand, a graph indicated by a broken line in FIG. 14 shows a simulation waveform in the case of a comparative example using a resistance element instead of the saturation current circuit 114 shown in FIG.

  From FIG. 14, the peak value of the surge voltage in this embodiment is reduced by 230 V compared to the peak value of the surge voltage when the saturation current circuit 114 is not used. Moreover, the Joule loss generated when the overcurrent was cut off was the same in both cases. Thus, according to the present embodiment, the surge voltage between the collector and the emitter of the IGBT 101 can be reduced.

(Second Embodiment)
FIG. 15 is a circuit diagram illustrating a main part of the power conversion device 251 according to the second embodiment. The current detection emitter electrode and the overcurrent detection circuit 108 provided in the IGBT 101 are not shown.
In this embodiment, an nMOSFET (metal-oxide-semiconductor junction field effect transistor) is used as the saturation current circuit 314. When the overcurrent is detected, the nMOSFET as saturation current circuit 314 is ON at the time of _{Q 3} shown in FIG. Further, the nMOSFET as the saturation current circuit 314 is turned on with a lower gate voltage than when the second switching element 112 is turned on.

In the power conversion apparatus 251 according to the present embodiment, similarly to the time chart shown in FIG. 4, during the time _{t 2} 'of the gate voltage _{V GE} from the time _{t 1} IGBT 101 becomes zero discharge direction of the gate current _{i G} The increase is clamped by the saturation current value I _SAT of the saturation current circuit 314 to prevent a sharp decrease in the gate voltage V _GE . Therefore, the rate of decrease in the collector current of the IGBT 101 becomes moderate, and the surge voltage applied between the collector and the emitter of the IGBT 101 can be suppressed.

  Thus, according to this embodiment, since the switching speed of IGBT101 can be suppressed, a surge voltage can be suppressed. Furthermore, in the present embodiment, the third switching element 113 shown in FIG. 3 can be deleted. Thereby, the nMOSFET can obtain the same voltage-current characteristics as shown in FIG. According to the present embodiment, in addition to the same effects as those of the first embodiment, the number of components of the power conversion device 251 can be reduced.

(Third embodiment)
FIG. 16 is a circuit diagram illustrating a main part of a power converter 251 according to the third embodiment. The current detection emitter electrode and the overcurrent detection circuit 108 provided in the IGBT 101 are not shown.
In this embodiment, an N-channel JFET is used as the saturation current circuit 414. When the overcurrent is detected, the JFET (junction field effect transistor) as the saturation current circuit 414 is ON at the time of Q ₃ shown in FIG. When turning off the JFET, a negative voltage is applied to the gate, and when turning on the JFET, a zero (GND) voltage is applied to the gate.

In the power conversion apparatus 251 according to the present embodiment, similarly to the time chart shown in FIG. 4, during the time _{t 2} 'of the gate voltage _{V GE} from the time _{t 1} IGBT 101 becomes zero discharge direction of the gate current _{i G} The increase is clamped by the saturation current value I _SAT of the saturation current circuit 414 to prevent a sharp decrease in the gate voltage V _GE . Therefore, the rate of decrease in the collector current of the IGBT 101 becomes moderate, and the surge voltage applied between the collector and the emitter of the IGBT 101 can be suppressed.

  Thus, according to this embodiment, since the switching speed of IGBT101 can be suppressed, a surge voltage can be suppressed. Furthermore, in the present embodiment, the third switching element 113 shown in FIG. 3 can be deleted. According to the present embodiment, in addition to the same effects as those of the first embodiment, the number of components of the power conversion device 251 can be reduced.

According to the embodiment described above, the following operational effects can be obtained.
(1) The power conversion device 251 is provided in the path of the IGBT 101 that is on / off controlled by the gate drive circuit 110 and the control current that turns off the IGBT 101, and the saturation that limits the control current to a predetermined saturation current and turns off the IGBT 101. And a current circuit 114. Thereby, the surge voltage of power semiconductor elements, such as IGBT101, can be reduced.

(Modification)
The present invention can be implemented by modifying the first to third embodiments described above as follows.
(1) In the first embodiment, the series circuit of the third switching element 113 and the saturation current circuit 114 is provided in parallel with the second switching element 112, but the second switching element 112 may be omitted. In this case, normal ON / OFF control of the IGBT 101 is performed by a series circuit of the third switching element 113 and the saturation current circuit 114. Further, when an overcurrent is detected in the IGBT 101, the IGBT 101 is controlled to be OFF.

(2) In the second to third embodiments, the saturation current circuits 314 and 414 are provided in parallel with the second switching element 112, but the second switching element 112 may be omitted. In this case, normal ON / OFF control of the IGBT 101 is performed by the saturation current circuits 314 and 414. Further, when an overcurrent is detected in the IGBT 101, the IGBT 101 is controlled to be OFF.

  The present invention is not limited to the above-described embodiment, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention as long as the characteristics of the present invention are not impaired. . Moreover, it is good also as a structure which combined the above-mentioned embodiment and a some modification.

101 IGBT
102 Diode 103 Gate capacitance 104, 105, 106, 107 Coupled inductor 110 Gate drive circuit 111 First switching element 112 Second switching element 113 Third switching element 114, 314, 414 Saturation current circuit 115, 116 Gate resistance 117 Gate power supply 118 Ground potential 122 Capacitor 150 Microcomputer circuit 201, 501 Power semiconductor module 202 Collector terminal 203 Emitter terminal 211, 511, 521 Gate terminal 212, 512, 522 Auxiliary emitter terminal 213, 513, 523 Current detection terminal 214, 215, 524, 525 Temperature detection terminal 251 Power conversion device 252, 253, 254 Housing 255 Smoothing capacitor 256 Bus bar 257 Circuit board 258 Channel 502 P terminal 03 N terminal 504 AC terminals 901 the battery 902 inverter circuit 903 connector

Claims (7)

A power semiconductor element that is on / off controlled by a gate drive circuit;
And a saturation current circuit that is provided in a control current path for turning off the power semiconductor element and limits the control current to a predetermined saturation current to turn off the power semiconductor element. The power conversion device according to claim 1,
The saturation current circuit is a power conversion device that suppresses a rate at which a gate voltage of the power semiconductor element is lowered when the power semiconductor element is turned off. The power conversion device according to claim 1,
Comprising an inverter circuit in which upper and lower arms are constituted by the power semiconductor element;
In the saturation current circuit, when the power semiconductor element is turned off, the gate voltage of the power semiconductor element is reduced by a coupled inductor formed between the path of the main current flowing through the inverter circuit and the path of the control current. A power converter that suppresses acceleration. In the power converter device as described in any one of Claim 1- Claim 3,
The saturation current circuit has a voltage-current characteristic in which a change in conduction current is 1.2 times or less in a voltage region between a threshold voltage of the power semiconductor element and a triple voltage of the threshold voltage. Power conversion device. In the power converter device as described in any one of Claim 1- Claim 3,
The said saturation current circuit is a power converter device comprised by the junction field effect transistor which restrict | limits the said control current to the said saturation current. In the power converter device according to claim 1 or 2,
An inverter circuit in which upper and lower arms are constituted by the power semiconductor element;
An overcurrent detection circuit for detecting an overcurrent in which a main current flowing through the inverter circuit is equal to or greater than a predetermined current,
The saturation current circuit is a power converter that limits the control current to the saturation current when the overcurrent is detected by the overcurrent detection circuit. The power conversion device according to claim 6, wherein
When the overcurrent is detected by the overcurrent detection circuit, the drive voltage of the saturation current circuit that turns off the power semiconductor element is lower than the drive voltage of the gate drive circuit.

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