CN114024538A - IGBT drive circuit - Google Patents

Abstract

The invention discloses an IGBT drive circuit, which is applied to an insulated gate bipolar transistor IGBT and comprises: drive chip, the IGBT that connects in parallel more than two and with the drive power amplifier circuit that every IGBT corresponds the setting, wherein: the output end of the driving chip is respectively connected with each driving power amplification circuit and used for providing a level driving signal for each driving power amplification circuit; each driving power amplifying circuit is connected with the base electrode of the corresponding IGBT, and the driving power amplifying circuits are used for converting the level driving signals into the driving voltage of the corresponding IGBT so as to drive the corresponding IGBT to work. The IGBT participating in parallel connection in each parallel connection group is provided with the independent driving power amplifying circuit, and power density of the controller is improved.

Description

IGBT drive circuit

Technical Field

The invention relates to the technical field of circuit design, in particular to an IGBT driving circuit.

Background

In the development of motor controllers for electric vehicles, power density is a key measure of controller performance. However, at present, the automotive high-power IGBT device still has limitations on voltage resistance and current capacity, and therefore, some effective measures are urgently needed to change the defect, so as to improve the power density of the motor controller.

Disclosure of Invention

The embodiment of the application provides an IGBT drive circuit, switches of a plurality of parallel IGBT power amplification circuit loops are controlled simultaneously through one drive chip, IGBT parallel drive is achieved, independent drive power amplification circuits are arranged for the IGBTs participating in parallel connection in each parallel connection group, and power density of a controller is improved.

In a first aspect, the present invention provides the following technical solutions through an embodiment of the present invention:

an IGBT drive circuit is applied to an Insulated Gate Bipolar Transistor (IGBT), and comprises: drive chip, the IGBT that connects in parallel more than two and with the drive power amplifier circuit that every IGBT corresponds the setting, wherein: the output end of the driving chip is respectively connected with each driving power amplification circuit and used for providing a level driving signal for each driving power amplification circuit; each driving power amplifying circuit is connected with the gate electrode of the corresponding IGBT, and the driving power amplifying circuits are used for converting the level driving signals into driving voltages of the corresponding IGBTs so as to drive the corresponding IGBTs to work.

Preferably, the driving power amplifying circuit includes: the power amplifier comprises a power amplification sub-circuit, a first power supply and energy storage sub-circuit and a second power supply and energy storage sub-circuit; the signal input end of the power amplification sub-circuit is connected with the output end of the driving chip, and the output end of the power amplification sub-circuit is connected with the gate pole of the corresponding IGBT and is used for converting the level driving signal into the driving voltage of the corresponding IGBT; the power supply ends of the first power supply energy storage sub-circuit and the second power supply energy storage sub-circuit are connected with a power supply circuit in the IGBT driving circuit, the power supply end of the first power supply energy storage sub-circuit is connected with the high-level input end of the power amplification sub-circuit, and the power supply end of the second power supply energy storage sub-circuit is connected with the low-level input end of the power amplification sub-circuit and used for providing working voltage for the power amplification sub-circuit.

Preferably, the first power supply energy storage sub-circuit and the second power supply energy storage sub-circuit are both formed by connecting a first capacitor and a second capacitor in parallel, wherein a capacitance value of the first capacitor is greater than a capacitance value of the second capacitor.

Preferably, the driving power amplifying circuit further includes: the gate electrode driving resistor, the gate electrode capacitor, the gate electrode pull-down resistor and the gate electrode clamping diode; one end of the gate driving resistor is connected with the output end of the power amplification sub-circuit, and the other end of the gate driving resistor, one end of the gate pull-down resistor, the positive electrode of the gate clamping diode, one end of the gate capacitor and the gate of the IGBT are connected with each other; the other end of the gate pull-down resistor, the other end of the gate capacitor and the emitter of the IGBT are all grounded, and the cathode of the gate clamping diode is connected with the high-level input end of the power amplification sub-circuit.

Preferably, the driving circuit further includes: and the isolation resistors are arranged in one-to-one correspondence with each power supply and energy storage sub-circuit in each driving power amplification circuit, one end of each isolation resistor is connected with the power supply circuit, and the other end of each isolation resistor is connected with the power supply end of the corresponding power supply and energy storage sub-circuit.

Preferably, the driving circuit further includes: and the temperature detection circuit is respectively connected with the junction temperature test end of each IGBT and is used for detecting the junction temperature signal of each IGBT and outputting the junction temperature signal with the highest detected junction temperature.

Preferably, the temperature detection circuit includes: the temperature gating sub-circuit, the highest temperature selection sub-circuit and the constant current source sub-circuits are arranged in one-to-one correspondence to the IGBTs; the power supply end of each constant current source sub-circuit is connected with the positive driving voltage of the power supply circuit in the IGBT driving circuit, and the output end of each constant current source sub-circuit is connected with the junction temperature testing end of the corresponding IGBT and used for providing constant current source current for the thermal diode in the IGBT to generate tube voltage drop and sending the tube voltage drop to the input ends of the temperature gating sub-circuit and the highest temperature selection sub-circuit; the output end of the highest temperature selection sub-circuit is connected with a selection port of the temperature gating sub-circuit, the highest temperature selection sub-circuit is used for comparing the received pipe voltage drop and outputting a level signal obtained by the comparison to the selection port of the temperature gating sub-circuit, and the temperature gating sub-circuit is used for gating the received pipe voltage drop based on the level signal and outputting a junction temperature signal with the highest junction temperature.

Preferably, the method further comprises the following steps: and the current detection circuits are arranged in one-to-one correspondence with the IGBTs and are connected with the current detection ends of the corresponding IGBTs and used for detecting the conduction current of the IGBT.

Preferably, the current detection circuit includes: the circuit comprises a sampling resistor, an RC filter sub-circuit, a clamping diode and an over-current comparison sub-circuit; one end of the sampling resistor is connected with the current detection end of the IGBT and the input end of the RC filter sub-circuit respectively, the other end of the sampling resistor is grounded, the output end of the RC filter sub-circuit is connected with the cathode of the clamping diode and the input end of the over-current comparison sub-circuit, the anode of the clamping diode is grounded, and the output end of the over-current comparison sub-circuit is used for outputting detected conduction current.

Preferably, the over-current comparator sub-circuit comprises an over-current comparator, an input end of the over-current comparator is connected with a cathode of the clamping diode, and an output end of the over-current comparator is used for outputting the detected conduction current.

One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

the embodiment of the invention provides an IGBT drive circuit, which comprises: drive chip, the IGBT that connects in parallel more than two and with the drive power amplifier circuit that every IGBT corresponds the setting, wherein: the output end of the driving chip is respectively connected with each driving power amplification circuit and used for providing a level driving signal for each driving power amplification circuit; each driving power amplifying circuit is connected with the gate pole of the corresponding IGBT and is used for converting the level driving signal into the driving voltage of the corresponding IGBT so as to drive the corresponding IGBT to work. The plurality of IGBTs are connected in parallel, each IGBT connected in parallel is provided with the independent driving power amplification circuit, so that the driving capacity of each IGBT is determined by the current capacity of the driving power amplification circuit, the output end of each driving chip is connected with each driving power amplification circuit, the driving signal source of each IGBT connected in parallel is unified, and the driving power amplification circuits can convert the level driving signals of the driving chips into the driving voltages of the corresponding IGBTs. This application comes the switch of a plurality of parallelly connected IGBT power amplification circuit return circuits of simultaneous control through using a driver chip to realize the parallelly connected drive of IGBT, and to the parallelly connected IGBT of participation in every parallel group, all have its independent drive power amplification circuit, improved controller power density.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic diagram of an IGBT driving circuit according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an IGBT temperature detection circuit provided in an embodiment of the present invention;

fig. 3 is a schematic diagram of an IGBT thermal diode constant current source sub-circuit provided in an embodiment of the present invention;

fig. 4 is a schematic diagram of an IGBT current detection circuit according to an embodiment of the present invention.

Detailed Description

The inventor finds that the existing automobile-grade high-power IGBT device has the limitations of voltage resistance and current capacity, the power density of the motor controller can be improved only by the series connection or parallel connection of the IGBT device, and the high-power inverter designed by the two methods has the advantages of simple structure, compatible control strategy, simple expansion and the like, so that the high-power inverter is low in cost, convenient for modular design and production and the like.

The voltage level of the inverter can be improved by connecting the IGBT devices in series, and the current level of the inverter can be improved by connecting the IGBT devices in parallel, so that the power level of the inverter is improved. Considering that the cost performance of the series connection mode is low, the IGBT parallel connection is a better choice for realizing the capacity expansion of the inverter.

In view of this, the present application provides an IGBT driving circuit, which uses one driving chip to simultaneously control the switches of multiple parallel IGBT power amplification circuit loops, so as to implement parallel driving of IGBTs, and for each parallel IGBT in each parallel group, there is an independent driving power amplification circuit, so as to improve the power density of the controller.

In order to solve the technical problems, the general idea of the embodiment of the application is as follows:

an IGBT drive circuit is applied to an Insulated Gate Bipolar Transistor (IGBT), and comprises: drive chip, the IGBT that connects in parallel more than two and with the drive power amplifier circuit that every IGBT corresponds the setting, wherein: the output end of the driving chip is respectively connected with each driving power amplification circuit and used for providing a level driving signal for each driving power amplification circuit; each driving power amplifying circuit is connected with the gate pole of the corresponding IGBT and is used for converting the level driving signal into the driving voltage of the corresponding IGBT so as to drive the corresponding IGBT to work.

In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.

In a first aspect, an embodiment of the present invention provides an IGBT driving circuit, specifically, as shown in fig. 1, the IGBT driving circuit includes: drive chip 10, two or more parallelly connected IGBTs and with the corresponding drive power amplifier circuit 20 that sets up of every IGBT, wherein: the output end of the driving chip 10 is respectively connected with each driving power amplifying circuit 20, and is used for providing a level driving signal to each driving power amplifying circuit; each driving power amplifying circuit 20 is connected to the gate of the corresponding IGBT, and the driving power amplifying circuit is configured to convert the level driving signal into the driving voltage of the corresponding IGBT so as to drive the corresponding IGBT to operate.

The driving chip 10 may be any chip capable of driving the IGBT, and the chip has protection and isolation functions, for example: IR2110, EXB841, M57962 and the like, which have the advantages of isolation driving, good circuit parameter consistency and stable operation.

The driving signal sources of all parallel IGBTs in the driving circuit are uniform and are all output from the same driving chip. Because each IGBT has its own independent drive circuit, the drive capability of IGBT is decided by the current capability of its own drive power amplifier circuit, and the drive capability of drive chip has decided the maximum parallel circuit number of IGBT.

Specifically, as shown in fig. 1, the driving power amplifying circuit 20 may include: a power amplification sub-circuit 201, a first supply tank sub-circuit 202 and a second supply tank sub-circuit 203. The signal input end of the power amplification sub-circuit 201 is connected with the output end of the driving chip 10, and the output end of the power amplification sub-circuit 201 is connected with the gate of the corresponding IGBT, and is used for converting the level driving signal into the driving voltage of the corresponding IGBT.

The power supply ends of the first power supply energy storage sub-circuit 202 and the second power supply energy storage sub-circuit 203 are both connected with the power supply circuit 40 in the IGBT driving circuit, the power supply end of the first power supply energy storage sub-circuit 202 is connected with the high-level input end VHx of the power amplification sub-circuit 201, and the power supply end of the second power supply energy storage sub-circuit 203 is connected with the low-level input end VLx of the power amplification sub-circuit 201, and is used for providing working voltage for the power amplification sub-circuit.

The positive driving voltage VH of the power supply circuit 40 in the IGBT driving circuit is set as the high-level input terminal VHx of the power amplification sub-circuit 201, and the negative driving voltage VL of the power supply circuit 40 in the IGBT driving circuit is set as the low-level input terminal VLx of the power amplification sub-circuit 201.

The power amplifier circuit 20 may be a push-pull circuit formed by a complementary NPN transistor and a PNP transistor, that is, an output circuit connected between two transistors with different polarities, and the power amplifier circuit can further amplify the electrical parameters (i.e., the voltage and the current) of the input signal.

For example, as shown in fig. 1, the power amplification circuit 20 may include: the base electrode of the NPN triode is connected with the base electrode of the PNP triode and serves as a signal input end of the power amplification circuit 20, the collector electrode of the NPN triode is connected with the high-level input end VHx, the emitter electrode of the NPN triode is connected with the emitter electrode of the PNP triode and serves as an output end of the power amplification circuit 20, and the collector electrode of the PNP triode is connected with the high-level input end VL x.

It should be noted that, if the driving chip 10 has an independent function of driving on and off output, the power amplifying circuit 20 may also be a push-pull circuit composed of P-MOS and N-MOS. Of course, any circuit that can convert the CMOS level driving signal of the driving chip into the IGBT driving voltage and can supply a sufficient driving current can be used as the power amplifying circuit.

Specifically, the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 can provide the power amplification circuit 201 with driving energy required for turning on and off the respective IGBTs. Since the driving power of the IGBT is mainly consumed during the time when the IGBT turns on and off, the power supply circuit 40 in the IGBT driving circuit supplies little energy to the IGBT when the IGBT turns on or off. Therefore, the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 can provide driving energy for the power amplifying circuit 201 nearby without taking power from the remote power circuit 40.

The first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 are disposed near the power amplification circuit 20, and the first power supply tank sub-circuit 202 is applied to the driving positive voltage VHx of the power supply circuit 40, and the second power supply tank sub-circuit 203 is applied to the driving negative voltage VLx of the power supply circuit 40.

As an alternative embodiment, the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 may both be composed of a first capacitor and a second capacitor connected in parallel, where a capacitance value of the first capacitor is greater than a capacitance value of the second capacitor. So that the first supply tank sub-circuit 202 and the second supply tank sub-circuit 203 are composed of a capacitor with a large capacitance value and a capacitor with a small capacitance value.

Specifically, in order to make the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 equivalent to independent voltage sources, the types of the first capacitor and the second capacitor may be selected from Multi-layer ceramic capacitors (MLCC), and the MLCC capacitor has low equivalent inductance ESL and low equivalent resistance ESR characteristics. In this way, each power amplifier circuit 20 in the parallel group has an independent driving power supply, instead of sharing the driving power supply circuit 40. Therefore, the driving commutation caused on the power supply loop can be effectively avoided, and the independence of each parallel IGBT driving loop flow path is ensured.

For example, the MLCC capacitor selected for use in the present application may be: NPO, COG, Y5V, Z5U, X7R or X5R, etc.

Of course, as another alternative embodiment, the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 may also have other structures, for example, the first power supply tank sub-circuit 202 and the second power supply tank sub-circuit 203 are both formed by a capacitor with a larger capacitance value.

Specifically, as shown in fig. 1, the driving power amplifying circuit 20 further includes: gate drive resistor R1, gate capacitor, gate pull-down resistor R2, and gate clamp diode 204. One end of the gate drive resistor R1 is connected to the output terminal of the power amplifier sub-circuit 201, and the other end of the gate drive resistor R1, one end of the gate pull-down resistor R2, the anode of the gate clamp diode 204, one end of the gate capacitor C1, and the gate G of the IGBT are connected to each other. The other end of the gate pull-down resistor R2, the other end of the gate capacitor C1, and the emitter E of the IGBT are all grounded VE, and the cathode of the gate clamp diode 204 is connected to the high-level input terminal VHx of the power amplification sub-circuit 201.

Among other things, the gate drive resistor R1 is capable of amplifying a logic (on/off) signal from the power amplification circuit 201 to provide sufficient drive current to the corresponding IGBT, provide level conversion from logic to gate, particularly high-side transistors, and the like. The gate pull-down resistor R2 can clamp the indeterminate signal at a low level through a resistor, thereby realizing the filtering effect. The gate capacitor C1 can play a role in resisting interference and improving the stability of the circuit. The gate clamp diode 204 can conduct the diode to pull down the potential of the positive terminal circuit when the cathode of the diode is grounded and the potential of the positive terminal circuit is higher than the ground, i.e. the positive terminal circuit is clamped to zero potential or below zero potential (neglecting the tube voltage drop); when the anode of the diode is grounded, the potential of the cathode circuit is higher than the ground, the diode is cut off, and the potential of the diode is not affected by any action of the diode.

Specifically, with the driving power amplifier circuit 20 provided in the embodiment of the present application, the turn-on commutation path of the IGBT is: the current flows from VE connected to the first power supply tank sub-circuit 202 to the gate driving resistor R1 through the gate capacitor C1, the gate pull-down resistor R2 and the anode of the gate clamp diode 204 to the gate of the IGBT, and flows to the emitter of the IGBT to VE.

Accordingly, the turn-off commutation path of the driving power amplification circuit 20 to the IGBT is: the current flows into the emitter of the IGBT from VE connected with the emitter of the IGBT, then flows out from the gate of the IGBT, passes through the gate capacitor C1, the gate pull-down resistor R2, and the positive electrode of the gate clamp diode 204, and then sequentially flows into the gate drive resistor R1 and the second power supply and storage sub-circuit 203 to VE.

Further, in order to enhance the independence of the first power supply energy storage sub-circuit 202 and the second power supply energy storage sub-circuit 203 and suppress the drive commutation, as shown in fig. 1, the IGBT drive circuit provided in the present application further includes: and the isolation resistors R3 are arranged in one-to-one correspondence with each power supply energy storage sub circuit in each driving power amplification circuit, one end of each isolation resistor R3 is connected with the power supply circuit 40, and the other end of each isolation resistor R3 is connected with the power supply end of the corresponding power supply energy storage sub circuit. Therefore, impedance between each parallel-connection-group driving power supply energy storage circuit can be increased, independence of the power supply energy storage sub-circuits is enhanced, and therefore when a plurality of IGBTs are connected in parallel, an independent driving loop can be provided for each IGBT, and mutual influence between parallel-connection IGBT drives is reduced.

For example, the isolation resistor R3 may be a magnetic bead or a large-resistance resistor, wherein the magnetic bead is capable of suppressing high-frequency noise and spike interference on the signal line and the power line, and further has an ability to absorb electrostatic pulses.

Further, in order to realize independent temperature detection of each parallel IGBT, as shown in fig. 2, the IGBT driving circuit provided in the embodiment of the present application may further include: and the temperature detection circuit 50 is respectively connected with the junction temperature test end Tj of each IGBT, and is used for detecting the junction temperature signal of each IGBT and outputting the junction temperature signal with the highest detected junction temperature.

Specifically, the temperature detection circuit 50 includes: a temperature gate sub-circuit 503, a maximum temperature selection sub-circuit 502, and constant current source sub-circuits 501 provided in one-to-one correspondence with each IGBT. The power supply terminal of each constant current source sub-circuit 501 is connected to the driving positive voltage VHx of the power supply circuit 40 in the IGBT driving circuit, and the output terminal of each constant current source sub-circuit 501 is connected to the junction temperature test terminal Tj of the corresponding IGBT, for supplying a constant current source current to the thermal diode in the IGBT to generate a tube voltage drop, and sending the tube voltage drop to the input terminals of the temperature gating sub-circuit 503 and the highest temperature selecting sub-circuit 502.

The output end of the highest temperature selection sub-circuit 502 is connected to a selection port of the temperature gating sub-circuit 503, the highest temperature selection sub-circuit 502 is configured to compare the received tube voltage drops and output a level signal obtained by the comparison to the selection port of the temperature gating sub-circuit 503, and the temperature gating sub-circuit 503 is configured to gate the received tube voltage drops based on the level signal and output a junction temperature signal with the highest junction temperature.

Specifically, the present application is directed to IGBTs having the functionality of providing IGBT junction temperature provided by their thermal diodes integrated on the IGBT wafer. The temperature measurement principle of the thermal diode is that when the current flowing through the thermal diode is constant, the tube voltage drop Vf and the junction temperature of the thermal diode are in a reverse linear change relationship. Therefore, in order to ensure the temperature measurement accuracy of the thermal diode, the constant current source sub-circuit 501 is additionally arranged to provide an independent constant current source circuit for the thermal diode.

As an alternative embodiment, the constant current source sub-circuit 501 may be a mirror current source, and an independent constant current source circuit is provided for the thermal diode by designing the mirror current source. Specifically, the constant current source circuit 21 takes power from the driving positive voltage VHx, a triode is used to build a mirror current source, the current value of the constant current source is adjusted through a resistor, the current of the constant current source flows through a thermal diode inside the IGBT to form a tube voltage drop Vf, and the Vf is filtered and then sent to the temperature gating sub-circuit 503 and the highest temperature selection sub-circuit 502.

For example, as shown in fig. 3, the IGBT thermal diode constant current source sub-circuit 501 may include: the circuit comprises a first triode, a second triode, a first resistor and a second resistor. The collector of the first triode 5010 and one end of the first resistor are both connected with the positive driving voltage +16V-UT of the power circuit 40, the base of the first triode is respectively connected with the other end of the first resistor and the collector of the second triode, the emitter of the first triode is respectively connected with one end of the second resistor and the base of the second triode, the emitter of the second triode is connected with the positive electrode of a thermal diode in the IGBT, and the negative electrode of the thermal diode and the other end of the second resistor are both grounded E-UT.

Therefore, each parallel IGBT is provided with the independent thermal diode constant current source sub-circuit 501, and the phenomenon that the driving current flows through the temperature detection circuit 50 in parallel to influence the driving consistency can be effectively avoided. Further, temperature detection signals of different IGBTs are sent to the temperature gating sub-circuit 503, and one path of signal with high junction temperature in the parallel IGBTs is sent out.

As an alternative embodiment, the temperature gating sub-circuit 503 may be a multi-channel analog switch, as shown in fig. 2, taking 2 IGBT modules connected in parallel as an example, the input of the temperature gating sub-circuit 503 is junction temperatures Tj1 and Tj2 of the 2 parallel IGBTs, and the output Vo is the one with higher temperature among Tj1 and Tj 2.

The maximum temperature selection sub-circuit 502 may consist of a temperature comparator circuit, the non-inverting (+) and inverting (-) terminals of which receive the junction temperatures Tj1 and Tj2, respectively. Since the voltage drop Vf of the thermal diode and the junction temperature Tj of the IGBT are in a negative temperature characteristic relationship, when Tj1> Tj2, the temperature comparator outputs a low level to the selection port of the temperature gating sub-circuit 503, and the temperature gating sub-circuit 503 outputs a value of Tj 1; when Tj1< Tj2, the temperature comparator outputs a high level to the select port of the temperature gating sub-circuit 503, and the temperature gating sub-circuit 503 outputs a value of Tj 2.

In brief, when the junction temperature at the in-phase end is higher than the junction temperature at the anti-phase end, the temperature gating sub-circuit 503 outputs the value at the in-phase end, and when the junction temperature at the in-phase end is lower than the junction temperature at the anti-phase end, the temperature gating sub-circuit 503 outputs the value at the anti-phase end.

It should be noted that the value of the voltage drop Vf of the thermal diode in the IGBT is a very sensitive quantity, and in general, a voltage value of 10mV corresponds to 1 ℃. When a general diode is used, the highest temperature selection sub-circuit 502 may have a great influence on the IGBT temperature detection due to the diode's pipe voltage drop fluctuation, for example: the common signal diode changes with the temperature, the tube voltage drop of the common signal diode changes by 0.1V, and the junction temperature converted to the IGBT is 10 ℃. The advantages of using the analog switch are: the on resistance of the signal path is extremely small, and the voltage drop of the signal cannot be generated, so that the output signal value is reduced, and the junction temperature Tj can be accurately detected.

Further, the voltage value Vo of the temperature signal output by the temperature gating sub-circuit 503 is a negative temperature coefficient, that is, the higher the junction temperature of the IGBT is, the smaller the value Vo is, so that the amplitude of Vo is too small at high temperature, which is not favorable for detection. Therefore, in order to facilitate the detection of the output signal of the temperature gating sub-circuit 503 and ensure the accuracy of temperature sampling, as shown in fig. 3, the temperature detection circuit 50 may further include: temperature modulation subcircuit 504, isolation subcircuit 505, and low pass filtering 506.

The output end of the temperature gating sub-circuit 503 is connected to the input end of the temperature modulating sub-circuit 504, the output end of the temperature modulating sub-circuit 504 is connected to the input end of the isolating sub-circuit 505, the output end of the isolating sub-circuit 505 is connected to the input end of the low-pass filter 506, and the output end of the low-pass filter 506 is used as the output end of the temperature detection circuit 50.

The temperature modulation sub-circuit 504 is configured to modulate a signal output by the temperature gating sub-circuit 503, the isolation circuit 505 is configured to isolate the modulated signal, and the low-pass filter 506 is configured to restore the signal to an analog voltage value for input to an analog-digital a/D port of a microprocessor, where the microprocessor is configured to detect and determine a received maximum temperature.

Specifically, the temperature modulation sub-circuit 504 may employ a PWM modulation circuit, and a PWM signal is obtained by comparing the temperature signal voltage value Vo with the triangular carrier Vtri in the PWM modulation circuit. The modulated IGBT junction temperature Tj and the PWM duty ratio are in a direct proportion relation, namely the higher the Tj is, the larger the PWM duty ratio is, and therefore detection is facilitated. The resulting PWM signal is then isolated by isolation circuit 505 and then passed to the low voltage side. For example, the isolation circuit 505 may be a transformer or an optocoupler, and the application is not limited thereto.

On the low side, the PWM voltage signal is low pass filtered 506 and restored to the analog voltage value Vpri, which is also proportional to Tj. The accuracy of temperature sampling can be guaranteed by inputting Vpri into the A/D port of the processor.

Of course, as another alternative embodiment, the PWM signal of the low voltage side may be directly sent to the a/D port of the processor.

Further, the IGBT driving circuit may further include: and the current detection circuits 60 are arranged in one-to-one correspondence with the IGBTs, and the current detection circuits 60 are connected with the current detection ends Is of the corresponding IGBTs and used for detecting the breakover current of the IGBTs.

As shown in fig. 4, the current detection circuit 60 may include: a sampling resistor R4, an RC filtering sub-circuit 601, a clamping diode 602, and an over-current comparison sub-circuit 603.

One end of the sampling resistor R4 Is connected with the current detection end Is of the IGBT and the input end of the RC filter sub-circuit 601 respectively, the other end of the sampling resistor R4 Is grounded, the output end of the RC filter sub-circuit 601 Is connected with the cathode of the clamping diode 602 and the input end of the over-current comparison sub-circuit 603, the anode of the clamping diode 602 Is grounded, and the output end of the over-current comparison sub-circuit 603 Is used for outputting detected conduction current.

It should be noted that, the IGBT to which the present application is directed integrates a mirror current source on an IGBT wafer, and can provide a current detection function of an IGBT on-current. Because a certain proportional relation exists between the output current of the mirror current source and the conduction current of the IGBT, the conduction current of each IGBT can be obtained by detecting the output current of the mirror current source, and overcurrent or short-circuit protection is carried out on each IGBT.

Specifically, first, the current mode signal of the mirror current source is converted into the voltage mode signal VIs by the sampling resistor R4. Of course, it is possible to use a circuit other than the sampling resistor R4 as long as it can convert the current signal of the mirror current source into a voltage signal, for example: a hall sensor or the like is used.

Further, since the current value of the current source output fluctuates sharply during the transient of the switching operation of the IGBT, the voltage value VIs flowing from the sampling resistor R4 is passed through the RC filter sub-circuit 601, and the ac component in the pulsating voltage is removed to obtain a smooth dc voltage. Then, the voltage value Vso flows into the clamp diode 602, and is clamped by the clamp diode 602, and then the obtained voltage value Vso is sent to the overcurrent comparison sub-circuit 603.

The over-current comparator circuit 603 may include an over-current comparator, an input end of the over-current comparator is connected to a negative electrode of the clamping diode 602, and an output end of the over-current comparator is configured to output an IGBT on-current.

Specifically, each IGBT in the parallel group has an independent over-current comparison sub-circuit 603. The over-current comparison circuit 603 is composed of an over-current comparator, a comparison threshold Vthoc of the over-current comparator can be obtained by dividing a driving voltage of the power supply voltage 40, and when Vso is greater than Vthoc, the over-current comparator outputs a high level to report an over-current fault; when Vso < Vthoc, the over-current comparator outputs a low level without an over-current fault.

As shown in fig. 4, taking 2 parallel IGBTs as an example, the current detection value Vso1 of the IGBT1 is fed to the first overcurrent comparison sub-circuit, and the current detection value Vso2 of the IGBT2 is fed to the second overcurrent comparison sub-circuit. When the first overcurrent comparator sub-circuit reports overcurrent faults, a high level is output; and the second over-current comparison sub-circuit still outputs a low level.

In addition, the over-current comparison sub-circuit 603 may further include a blocking diode, which blocks the low level output by the over-current comparator, so that only the high level of the over-current comparison sub-circuit 603 is output to the fault protection pin of the driving chip 40, and when the fault protection pin of the driving chip 40 receives a high level signal, an over-current fault is reported, thereby implementing independent over-current and short-circuit detection on each parallel IGBT.

The scheme provided by the embodiment of the application has at least the following advantages:

1. the IGBT modules participating in parallel connection in each parallel connection group are provided with independent driving power amplification circuits, so that the power density of the controller is improved; 2. the mirror current source current is adopted to provide an independent constant current source circuit for the thermal diode, so that the temperature measurement precision of the thermal diode is ensured, the parallel driving circulation current is prevented from flowing through the temperature measurement circuit, and the driving consistency is ensured; 3. an independent temperature detection circuit, a current detection circuit and a short-circuit protection circuit are designed for each parallel IGBT module, so that independent detection and protection of each parallel IGBT are realized.

Therefore, the IGBT driving circuit provided by the application controls the parallel IGBT through one driving chip, and the driving circuit is provided with an independent push-pull amplification circuit loop, a temperature detection circuit, a current detection circuit, short-circuit protection and over-temperature protection. The temperature detection circuit can be understood as that the temperature of the two is sampled and compared, the analog switch is triggered, the channel is opened, and a signal with high temperature is sent to the processor for processing; the current detection circuit can be understood as that after the overcurrent protection threshold voltage is set to be compared with the current signal, whether overcurrent occurs is judged to carry out protection, and any one path of IGBT can trigger protection when overcurrent occurs. According to the IGBT parallel protection device, the power density of the controller can be improved, meanwhile, the IGBT parallel driving and multiple protection functions are provided for the controller, and each parallel IGBT can be detected and protected. On the premise of realizing the static and dynamic current sharing of the parallel connection of the IGBTs, the parallel connection driving scheme and the peripheral circuit are simplified, and the research and development design of the high-power motor controller is facilitated.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. An IGBT drive circuit is characterized by being applied to an Insulated Gate Bipolar Transistor (IGBT), and comprising: drive chip, the IGBT that connects in parallel more than two and with the drive power amplifier circuit that every IGBT corresponds the setting, wherein:

the output end of the driving chip is respectively connected with each driving power amplification circuit and used for providing a level driving signal for each driving power amplification circuit;

each driving power amplifying circuit is connected with the gate electrode of the corresponding IGBT, and the driving power amplifying circuits are used for converting the level driving signals into driving voltages of the corresponding IGBTs so as to drive the corresponding IGBTs to work.

2. The drive circuit according to claim 1, wherein the drive power amplification circuit comprises: the power amplifier comprises a power amplification sub-circuit, a first power supply and energy storage sub-circuit and a second power supply and energy storage sub-circuit;

the signal input end of the power amplification sub-circuit is connected with the output end of the driving chip, and the output end of the power amplification sub-circuit is connected with the gate pole of the corresponding IGBT and is used for converting the level driving signal into the driving voltage of the corresponding IGBT;

the power supply ends of the first power supply energy storage sub-circuit and the second power supply energy storage sub-circuit are connected with a power supply circuit in the IGBT driving circuit, the power supply end of the first power supply energy storage sub-circuit is connected with the high-level input end of the power amplification sub-circuit, and the power supply end of the second power supply energy storage sub-circuit is connected with the low-level input end of the power amplification sub-circuit and used for providing working voltage for the power amplification sub-circuit.

3. The driving circuit as claimed in claim 2, wherein the first power supply energy storage sub-circuit and the second power supply energy storage sub-circuit are each formed by a first capacitor and a second capacitor connected in parallel, wherein a capacitance value of the first capacitor is greater than a capacitance value of the second capacitor.

4. The drive circuit according to claim 2, wherein the drive power amplification circuit further comprises: the gate electrode driving resistor, the gate electrode capacitor, the gate electrode pull-down resistor and the gate electrode clamping diode;

one end of the gate driving resistor is connected with the output end of the power amplification sub-circuit, and the other end of the gate driving resistor, one end of the gate pull-down resistor, the positive electrode of the gate clamping diode, one end of the gate capacitor and the gate of the IGBT are connected with each other;

the other end of the gate pull-down resistor, the other end of the gate capacitor and the emitter of the IGBT are all grounded, and the cathode of the gate clamping diode is connected with the high-level input end of the power amplification sub-circuit.

5. The drive circuit of claim 2, further comprising:

and the isolation resistors are arranged in one-to-one correspondence with each power supply and energy storage sub-circuit in each driving power amplification circuit, one end of each isolation resistor is connected with the power supply circuit, and the other end of each isolation resistor is connected with the power supply end of the corresponding power supply and energy storage sub-circuit.

6. The drive circuit of claim 1, further comprising:

and the temperature detection circuit is respectively connected with the junction temperature test end of each IGBT and is used for detecting the junction temperature signal of each IGBT and outputting the junction temperature signal with the highest detected junction temperature.

7. The drive circuit according to claim 6, wherein the temperature detection circuit includes: the temperature gating sub-circuit, the highest temperature selection sub-circuit and the constant current source sub-circuits are arranged in one-to-one correspondence to the IGBTs;

the power supply end of each constant current source sub-circuit is connected with the positive driving voltage of the power supply circuit in the IGBT driving circuit, and the output end of each constant current source sub-circuit is connected with the junction temperature testing end of the corresponding IGBT and used for providing constant current source current for the thermal diode in the IGBT to generate tube voltage drop and sending the tube voltage drop to the input ends of the temperature gating sub-circuit and the highest temperature selection sub-circuit;

the output end of the highest temperature selection sub-circuit is connected with a selection port of the temperature gating sub-circuit, the highest temperature selection sub-circuit is used for comparing the received pipe voltage drop and outputting a level signal obtained by the comparison to the selection port of the temperature gating sub-circuit, and the temperature gating sub-circuit is used for gating the received pipe voltage drop based on the level signal and outputting a junction temperature signal with the highest junction temperature.

8. The drive circuit of claim 1, further comprising:

and the current detection circuits are arranged in one-to-one correspondence with the IGBTs and are connected with the current detection ends of the corresponding IGBTs and used for detecting the conduction current of the IGBT.

9. The drive circuit of claim 8, wherein the current sense circuit comprises: the circuit comprises a sampling resistor, an RC filter sub-circuit, a clamping diode and an over-current comparison sub-circuit;

one end of the sampling resistor is connected with the current detection end of the IGBT and the input end of the RC filter sub-circuit respectively, the other end of the sampling resistor is grounded, the output end of the RC filter sub-circuit is connected with the cathode of the clamping diode and the input end of the over-current comparison sub-circuit, the anode of the clamping diode is grounded, and the output end of the over-current comparison sub-circuit is used for outputting detected conduction current.

10. The driving circuit of claim 9, wherein the over-current comparator sub-circuit comprises an over-current comparator, an input terminal of the over-current comparator is connected to a cathode of the clamping diode, and an output terminal of the over-current comparator is used for outputting the detected on-current.

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