CN210297240U

CN210297240U - IGBT short-circuit fault rapid protection circuit

Info

Publication number: CN210297240U
Application number: CN201920970717.7U
Authority: CN
Inventors: 张经纬; 耿程飞; 杜祥威
Original assignee: China Mining Drives and Automation Co Ltd
Current assignee: Jiangsu Guochuan Electric Co ltd
Priority date: 2019-06-25
Filing date: 2019-06-25
Publication date: 2020-04-10
Anticipated expiration: 2029-06-25

Abstract

The utility model provides a quick protection circuit of IGBT short circuit fault, including short circuit detection circuitry, gate logic circuit and amplifier circuit. And the change state of different gate voltage and collector voltage when the short circuit occurs is compared with the normal opening state to detect the short circuit fault, and the push-pull amplification circuit is controlled by the logic circuit to turn off the IGBT in time. The utility model discloses can improve short-circuit fault detection rate, required short-circuit detection device and detection circuitry are simple, realize easily.

Description

IGBT short-circuit fault rapid protection circuit

Technical Field

The utility model relates to a quick protection circuit of IGBT short-circuit fault belongs to power electronic technology field.

Background

The short-circuit protection of the IGBT is a key factor for improving the reliability of a power electronic system. The conventional method of failsafe and short-circuit protection is to detect the collector-emitter voltage of the IGBT to determine whether an IGBT short-circuit fault has occurred. Blanking circuits need to be provided in this protection method to avoid false triggering of short circuit protection during IGBT turn-on transients. However, in order to make the driving board have universality, a longer blanking time is generally required to be set, so that short-circuit loss is increased, junction temperature is increased, and impact of short-circuit fault on the device is increased. In addition to the failsafe method, the currently used method is to extract two aspects of short-circuit protection from the short-circuit current information and the gate information, such as: the short-circuit current is extracted by using the induced potential between the power emitter and the auxiliary emitter according to the change of the gate voltage or the gate charge at the time of the short-circuit fault. However, compared with the traditional method of depreciation and protection, a large number of operational amplifiers are generally needed to extract information, and parameter design of a detection circuit is needed according to a specific application environment, so that the method is poor in universality and is not widely applied. It is therefore important to develop a short-circuit protection that can improve the short-circuit protection rate without requiring excessive detection elements.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the not enough in the prior art, provide a quick protection method of IGBT short-circuit fault and circuit. The circuit can improve the short-circuit protection rate, and the technical scheme is as follows:

an IGBT short-circuit fault rapid protection circuit, comprising: a short circuit detection circuit, a gate logic circuit and an amplification circuit;

the short circuit detection circuit detects the states of the collector voltage and the gate voltage to judge whether a short circuit fault occurs or not and outputs a fault signal to the gate logic circuit;

the gate logic circuit judges whether the IGBT to be tested needs to be switched on or switched off according to the PWM switching signal and the fault signal of the external controller, and outputs a control signal to the amplifying circuit;

the amplifying circuit outputs a positive driving voltage V to the IGBT according to the control signal output by the gate logic circuit_CCOr a negative drive voltage V_EEThe on and off of the IGBT are realized;

wherein: the gate logic circuit receives the switching signal V_pwmAnd a fault signal V_faultAnd outputs a control signal V to the amplifying circuit_p(ii) a Short circuit detectionCircuit detects IGBT's that awaits measuring collector voltage V_CEAnd gate voltage V_GAnd outputs a fault signal V to the gate logic circuit_fault(ii) a The amplifying circuit receives the control signal V_pAnd the output end of the power supply is connected with the gate pole of the IGBT to be tested.

As an improvement of the utility model, the short circuit detection circuit, include: a collector detection circuit, a gate detection circuit and a fault judgment circuit; wherein: collector voltage V detected by collector detection circuit at input end of collector detection circuit_CEThe output end of the fault judging circuit is connected with the first input end of the fault judging circuit; gate pole voltage V detected by input end of gate pole detection circuit_GThe output end of the fault judging circuit is connected with the second input end of the fault judging circuit; fault signal V output by fault judging circuit output end_fault。

As an improvement of the utility model, collecting electrode detection circuitry, real-time detection collecting electrode voltage state, include: diode D₁Diode D₂Diode D₃Resistance R₁Capacitor C₁Switch Q₁(ii) a Wherein: diode D₁The cathode of the IGBT is connected with the collector of the IGBT to be tested, the anode of the IGBT is connected with one end of a resistor R1, and a capacitor C₁One terminal of (D), diode D₂Anode of (2), diode D₃P-type switching tube Q₁Is connected to the other end of the resistor R1, and a diode D₂Cathode of (2) and P-type switching tube Q₁And a positive driving voltage V_CCConnecting; capacitor C₁Another terminal of (1) and a diode D₃The anode of (2) is grounded.

As an improvement of the utility model, the gate pole detection circuit adopts a diode D₄Real-time detection of gate state, diode D₄The anode of the IGBT is connected with the gate pole of the IGBT to be tested.

As an improvement of the utility model, the fault judgment circuit, according to the change state of gate pole voltage and collector voltage, judges whether short-circuit fault takes place, and to gate logic circuit output fault signal, include: resistance R₂Resistance R₃Resistance R₄P-type switch tube Q₂Wherein: resistance R₂One end of the P-type switch tube Q₁Collector of (2), P-type switching tube Q₂Base electrode of (3), resistor R₃One end of the two ends are connected; resistance R₃Is connected with a reference voltage V at the other end_ref(ii) a Resistance R₂Another terminal of (1) and a diode D₄P-type switching tube Q₂Is connected with the emitting electrode of the P-type switching tube Q₂Collector and resistor R₄Is connected to output a fault signal V_fault(ii) a Resistance R₄And the other end of the negative driving voltage V_EEAre connected.

As an improvement of the present invention, the P-type switch tube Q₁And Q₂And a power switching device with a faster switching speed, such as a BJT or a MOSFET, is adopted.

As an improvement of the utility model, the gate logic circuit can adopt AND gate or NAND gate chip to build the logic circuit, also can adopt digital chip FPGA/CPLD to carry out logic control.

As an improvement of the present invention, the gate pole and the collector voltage detection circuit, the reference voltage V_refThe value of (d) is between the Miller platform voltage and the positive drive voltage V of the IGBT_CCIn the meantime.

Compared with the prior art, the utility model has the advantages of it is following:

the utility model discloses according to the influence of short-circuit fault to gate pole and collecting electrode, through real-time detection gate pole voltage and collecting electrode voltage, the blanking time that quick judgement short-circuit fault set up for preventing the wrong report trouble that the normal process of opening takes place in the traditional saturation method that moves back has been eliminated, has improved the protection rate of short circuit.

The utility model discloses detection circuitry is simple, and need not to adopt operational amplifier to carry out the parameter and draw, has reduced circuit cost and circuit area, and the commonality is better.

Drawings

The present invention will be further explained with reference to the accompanying drawings:

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a block diagram of a short circuit detection circuit;

FIG. 3 is a schematic circuit diagram of the present invention;

FIG. 4 is a schematic diagram of waveforms when the IGBT is normally switched on and off;

FIG. 5 is a schematic diagram of waveforms for short-circuit protection of an IGBT during a turn-on transient state;

FIG. 6 is a schematic diagram of waveforms for short-circuit protection of an IGBT in a conducting state;

FIG. 7 is a schematic diagram of the arrangement of the gate clamp circuit;

FIG. 8 is a schematic diagram of waveforms for short-circuit protection of an IGBT in the on state after a gate clamping circuit is provided;

FIG. 9 is a schematic diagram of a soft turn-off circuit;

FIG. 10 is an experimental waveform of the IGBT during the on transient state with short circuit protection by the conventional method;

FIG. 11 is an experimental waveform for protecting the IGBT in the short circuit in the switching-on transient state;

fig. 12 is an experimental waveform of protection of an IGBT in a short circuit state by a conventional method;

fig. 13 is an experimental waveform for short circuit of the IGBT in the on state to be protected by the present invention;

the specific implementation mode is as follows:

in order to clearly understand the present invention, the following description is made with reference to the accompanying drawings and the embodiments.

Example 1:

the connection relationship of the units of the present invention is shown in fig. 1.

The method comprises the following steps: short circuit detection circuit, gate logic circuit and amplifier circuit. Wherein: the gate logic circuit receives the switching signal V_pwmAnd a fault signal V_faultAnd outputs a control signal V to the amplifying circuit_p(ii) a Short-circuit detection circuit for detecting collector voltage V of IGBT to be detected_CEAnd gate voltage V_GAnd outputs a fault signal V to the gate logic circuit_fault(ii) a The amplifying circuit receives the control signal V_pAnd the output end of the power supply is connected with the gate pole of the IGBT to be tested.

Short circuit detection circuit for detecting the sum of collector voltagesThe state of the gate voltage to determine whether a short circuit fault has occurred and to output a fault signal to the gate logic circuit, comprising: collector detection circuit, gate pole detection circuit, failure judgment circuit. The short circuit detection circuit connection relationship is shown with reference to fig. 2, in which: collector voltage V detected by collector detection circuit at input end of collector detection circuit_CEThe output end of the fault judging circuit is connected with the first input end of the fault judging circuit; gate pole voltage V detected by input end of gate pole detection circuit_GThe output end of the fault judging circuit is connected with the second input end of the fault judging circuit; fault signal V output by fault judging circuit output end_fault。

A schematic diagram of each unit specific device provided in this embodiment is shown in fig. 3.

Collecting electrode detection circuitry, real-time detection collecting electrode voltage state includes: diode D₁Diode D₂Diode D₃Resistance R₁Capacitor C₁Switch Q₁. Wherein: diode D₁The cathode of the IGBT is connected with the collector of the IGBT to be tested, the anode of the IGBT is connected with one end of a resistor R1, and a capacitor C₁One terminal of (D), diode D₂Anode of (2), diode D₃P-type switching tube Q₁Is connected with the base electrode of the substrate; the other end of the resistor R1, diode D₂Cathode of (2) and P-type switching tube Q₁And a positive driving voltage V_CCConnecting; capacitor C₁Another terminal of (1) and a diode D₃The anode of (2) is grounded.

Gate detection circuit using diode D₄Real-time detection of gate state, diode D₄The anode of the IGBT is connected with the gate pole of the IGBT to be tested.

The fault judging circuit judges whether short-circuit fault occurs according to the change state of the gate voltage and the collector voltage, and outputs a fault signal to the gate logic circuit, and comprises: resistance R₂Resistance R₃Resistance R₄P-type switch tube Q₂Wherein: resistance R₂One end of the P-type switch tube Q₁Collector of (2), P-type switching tube Q₂Base electrode of (3), resistor R₃One end of the two ends are connected; resistance R₃Is connected with a reference voltage V at the other end_ref(ii) a Resistance R₂Another terminal of (1) and a diode D₄P-type switching tube Q₂Is connected with the emitting electrode of the P-type switching tube Q₂Collector and resistor R₄Is connected to output a fault signal V_fault(ii) a Resistance R₄And the other end of the negative driving voltage V_EEAre connected.

Gate and collector voltage detection circuit, switch Q₁And Q₂And a power switching device with a faster switching speed, such as a BJT or a MOSFET, is adopted.

The gate logic circuit is used for judging whether the IGBT to be tested needs to be switched on or switched off according to the PWM switching signal and the fault signal of the external controller and outputting a control signal to the amplifying circuit; a logic circuit can be built by adopting an AND gate chip or an NAND gate chip, and a digital chip FPGA/CPLD can also be adopted for logic control; in this embodiment, an and gate or nand gate chip is used to build a logic circuit, as shown in fig. 3, including: NOT gate U₁OR gate U₂NAND gate U₃AND gate U₄(ii) a Wherein: NOT gate U₁A first input terminal of receives a switching signal V_pwm，U₁And U₂And U and a second input and an output of₃Is connected with the first input end of the first input end; OR gate U₂Receives a fault signal V_faultA second input terminal and U₁Are connected to the output terminal of U₂And U₂And U and a second input terminal of₃Is connected with the first input end of the first input end; NAND gate U₃First input terminal and U₂Is connected with the output end of the first input end, and the second input end receives a switching signal V_pwm(ii) a AND gate U₄First input terminal and U₃Is connected with the output end of the first input end, and the second input end receives the control signal V_pwm(ii) a AND gate U₄Output terminal of the control circuit outputs a control signal V_p。

An amplifier circuit for outputting a positive drive voltage V to the IGBT according to the control signal output from the gate logic circuit_CCOr a negative drive voltage V_EEThe on and off of the IGBT are realized; the method comprises the following steps: n-type switch tube Q_nP-type switch tube Q_pAnd gate resistance R_g(ii) a Wherein: n-type switch tube Q_nIs transmitted byPole and P type switch tube Q_pEmitter, gate resistance R_gOne end of the two ends are connected; gate resistance R_gThe other end of the diode (D) is connected with an IGBT gate pole to be tested and a diode (D)₄The anodes of the anode groups are connected; n-type switch tube Q_nIs connected to a positive drive voltage V_CC(ii) a P-type switch tube Q_pCollector electrode of the collector is connected with a negative driving voltage V_EE(ii) a N-type switch tube Q_nBase and P-type switch tube Q_pBase electrode of the transistor receives a control signal V_p。

The utility model discloses a short-circuit protection principle does:

(1) at normal turn-on transient, at gate voltage V_GUp to a reference voltage V_refAt this time, the collector voltage has already dropped to the turn-on voltage drop by the high voltage.

The normal switching process of the IGBT is shown in fig. 4.

At t₀Before the moment, the switching signal V_pwmFor turning off the signal, the amplifying circuit supplies a negative drive voltage V to the gate_EEThe IGBT to be tested is in a turn-off state, and the collector side V_CEBearing full bus voltage V_DCAnd thus the voltage Va at point a is clamped to the positive drive voltage V_CCUpper, P type switch tube Q₁Is in an off state, and the voltage V at the point b_bAnd voltage V at point c_cAre all equal to a reference voltage V_refThus P-type switch tube Q₂The off state is maintained. Fault signal V_faultOutput voltage of V_EEAnd no short-circuit fault is output.

At t₀Time of day, switching signal V_pwmThe amplifier circuit is switched to an ON signal and the amplifier circuit is switched to a positive voltage V_CCGate voltage V_GStarting to rise, the collector voltage V before rising to the Miller plateau voltage_CEP-type switching tube Q with high voltage₁Still remains in the off state, voltage V at point b_bAnd voltage V at point c_cRemains unchanged, so that the P-type switching tube Q₂Remaining in the off state, fault signal V_faultThe output voltage does not output a short circuit fault.

After entering the Miller stage, V_CERapidly dropping to the conduction voltage drop. At t₁Time, voltage V at point aa is less than the positive drive voltage V_CCSo that the P-type switch tube Q₁Is turned on, thereby the voltage V at the point b_bAnd voltage V at point c_cConversion to positive drive voltage V_CCP-type switch tube Q₂Remaining in the off state, fault signal V_faultNo short-circuit fault is output.

Thereafter the IGBT enters the conducting state, V_GContinuously rising, voltage V at point b_bAnd voltage V at point c_cAlways keep V_CCOf fault signal V_faultNo short-circuit fault is output.

At t₃Time of day, switching signal V_pwmThe amplifier circuit is switched to an off signal and the negative driving voltage V is switched to the amplifying circuit_EEGate voltage V_GBegins to rapidly drop to a Miller plateau voltage less than a reference voltage V_refVoltage V at point b_bAnd voltage V at point c_cIs still maintained at the positive drive voltage V_CC(ii) a With collector voltage V_CEGradually increases from conduction voltage drop to t₄At the time point, the voltage Va at the point a starts to be clamped at the positive drive voltage V_CCTo make the P-type switch tube Q₁Off, voltage V at point b_bAnd voltage V at point c_cConversion to a reference voltage V_ref(ii) a During the whole turn-off process, the voltage V at the point b_bIs always equal to the voltage V at the point c_cThus P-type switch tube Q₂Remaining in the off state, fault signal V_faultNo short-circuit fault is output.

(2) When the short circuit occurs in the turn-on transient state of the IGBT to be tested, the gate pole rises to the reference voltage V_refTime, collector voltage V_CEThe voltage is kept high, the short circuit detection circuit identifies short circuit faults according to the high voltage, and the gate logic circuit controls the amplifying circuit to rapidly switch off the IGBT to be detected.

The protection process of the IGBT to be tested in the on transient state with short circuit is shown in fig. 5.

At t₅Time of day, switching signal V_pwmThe switch is switched from off signal to on signal, and the amplifying circuit is switched to positive voltage V_CCGate voltage V_GStarts to rise continuously, generates short-circuit fault and is influenced by desaturation effect, and the collector voltage V_CEAlways keeping high voltage, the voltage Va at point a is clamped at the positive driving voltage V_CCUpper, P type switch tube Q₂Remains in an off state, and thus a voltage V at a point b_bAnd voltage V at point c_cIs a reference voltage V_ref。

At time t6, gate voltage V_GWill be higher than the reference voltage V_refVoltage V at point b_bAnd voltage V at point c_cStart to rise with R₂And R₃Form a divided voltage, voltage V at point b_bAnd voltage V at point c_cRespectively as follows:

wherein: VD₄Is a diode D₄The conduction voltage drop of (1).

At this time, the voltage V at the point b_bVoltage V initially lower than point c_cSo that the P-type switch tube Q₂Open, fault signal V_faultAnd converting to high level and outputting short-circuit fault. The gate logic circuit immediately controls the amplifier circuit after receiving the short-circuit fault, and supplies a negative driving voltage V to the gate at time t7_EEAnd turning off the IGBT to be tested.

(3) When short circuit occurs in the on state of the IGBT to be tested, if no gate clamping circuit exists, the gate voltage V is generated in the process that the collector current rapidly rises_GA voltage spike occurs, and the collector V is at this time_CEIn order to conduct the voltage drop, the short circuit detection circuit identifies the short circuit fault according to the short circuit fault, and the gate logic circuit controls the amplifying circuit to rapidly turn off the IGBT to be tested.

The protection process of the IGBT to be tested when short circuit occurs in the on state is shown in fig. 6.

At t₈At the moment, the IGBT to be tested is in short circuit fault due to the fact that an external device is switched on, the current of a collector rapidly rises, the inductance of an emitter generates induction potential, and gate voltage V is caused_GGenerating a voltage peak to convert the voltage V at the point c_cIs raised, at this time, due to the collector voltage V_CEIs still conducted voltage drop, P-type switch tube Q₁In the on state, a voltage V at point b_bIs still a positive drive voltage V_CCAnd thus the voltage V at point b_bVoltage V less than point c_cP-type switch tube Q₂Open, fault signal V_faultAnd converting to high level and outputting short-circuit fault. The gate logic circuit immediately controls the amplifier circuit after receiving the short-circuit fault, and supplies a negative driving voltage V to the gate at time t9_EEAnd turning off the IGBT to be tested.

Example 2:

if a gate clamp is provided in the amplifier circuit, as shown in FIG. 7. The anode of the diode D5 is connected with the gate pole of the IGBT to be tested, and the cathode is connected with the positive driving voltage V_CC。

When the short circuit occurs in the on state of the IGBT to be tested, the gate pole clamping circuit restrains the gate pole voltage spike, no obvious voltage spike can be generated, the collector current continuously rises to enable the IGBT to be tested to begin to generate the desaturation phenomenon, and the collector voltage V is_CEThe conduction voltage drop rapidly rises to high voltage, the short circuit detection circuit identifies short circuit faults according to the high voltage, and the gate logic circuit controls the amplifying circuit to rapidly turn off the IGBT to be detected.

The protection process of the IGBT to be tested when short circuit occurs in the on state is shown in fig. 8.

At t₈At time, the collector current rises rapidly, at t₈-t₉The intra-phase gate clamp suppresses the gate voltage spike. When the IGBT to be tested begins to generate desaturation, the voltage V of the collector electrode_CERises rapidly and at t₉At the moment, the voltage Va at the point a is clamped at the positive driving voltage V_CCUpper, P type switch tube Q₁In an off state, a voltage V at a point b_bFrom a positive drive voltage V_CCThe following steps are changed:

at this time, the voltage V at the point b_bVoltage V less than point c_cThen P-type switch tube Q₂Open, fault signal V_faultAnd the IGBT is converted into a high level, short-circuit faults are output, the gate logic circuit controls the amplifying circuit, and the IGBT to be tested is quickly switched off.

The short-circuit protection time point of this embodiment is delayed backward compared to when the gate clamp is not provided.

Example 3:

when the amplifying circuit is provided with a soft-off circuit, as shown in fig. 9, the soft-off circuit of the amplifying circuit includes: p-type switch tube Qs and resistor R_gsWherein: collector of P-type switch tube Qs and negative driving voltage V_EEConnected to an emitter electrode and a resistor R_gsIs connected to one end of a resistor R_gsThe other end of the power supply is connected with a gate pole of the IGBT to be tested.

The AND gate or NAND gate chip that this embodiment adopted builds logic circuit, includes: NOT gate U₁OR gate U₂NAND gate U₃AND gate U₄(ii) a Wherein: NOT gate U₁A first input terminal of receives a switching signal V_pwm，U₁And U₂And U and a second input and an output of₃Is connected with the first input end of the first input end; OR gate U₂Receives a fault signal V_faultA second input terminal and U₁Are connected to the output terminal of U₂And U₂And U and a second input terminal of₃Is connected with the first input end of the first input end; NAND gate U₃First input terminal and U₂Is connected with the output end of the first input end, and the second input end receives a switching signal V_pwm(ii) a AND gate U₄First input terminal and U₃Is connected with the output end of the first input end, and the second input end receives the control signal V_pwm(ii) a AND gate U₄Output terminal of the control circuit outputs a control signal V_p. Control signal V_pN-type switching tube Q for controlling amplifying circuit_nAnd a soft turn-off switch tube Q_sOn and off. Switching signal V_pwmP-type switching tube Q for controlling amplifying circuit_pOn and off.

The soft turn-off circuit is arranged to avoid that when the short-circuit fault is turned off, the too high collector current change rate causes the too high voltage spike of the collector voltage, thereby preventing the breakdown of the IGBT.

When the circuit is normally turned off, the amplifying circuit realizes normal turn-off, and when short circuit occurs, the gate logic circuit turns on the soft turn-off circuit, so that the turn-off process is slowed down, and turn-off overvoltage is reduced.

Example 4:

the IGBT module adopts FF1400R17IP4 of England flying company, and positive driving voltage V in the amplifying circuit_CCIs 15V, a negative driving voltage V_EEis-15V, reference voltage V_refA12V zener diode of type MM1Z12 is used. The types of other devices of the short circuit detection circuit are respectively as follows: q_nZXTN2010Z, Q_pZXTP2012Z, Q1 and Q2 are S8050, D1 is STTH112U, D2 and D3 are BAV 99. When a short circuit occurs at the turn-on transient of the IGBT to be tested, the conventional short circuit waveform is shown in fig. 10. The device to be tested is switched on at 4 mus, and the short-circuit current continuously rises. Due to the blanking time, the device to be tested is turned off only by driving at 11 mus, and the maximum short-circuit current is 4.3kA at this moment. Compared with the conventional short circuit waveform, the short circuit waveform of the present invention is shown in fig. 11. And similarly, the IGBT to be tested is switched on at 4 mu s, when the gate voltage rises to 12V, the amplifying circuit detects the short-circuit fault, and the IGBT to be tested is switched off at 7.4 mu s. The maximum short-circuit current at this moment is only 2.9 kA.

When a short circuit occurs in the on state of the IGBT to be tested, a conventional short circuit waveform is shown in fig. 12. The IGBT to be tested has short-circuit fault at 25.1 mu s, and the IGBT to be tested is turned off after 4.1 mu s by the traditional method. The maximum short-circuit current at this time was 4.2 kA. The short circuit waveform of the present invention is shown in fig. 13. And similarly, the IGBT to be tested has short-circuit fault after 25.1 mu s, at the moment, the drive detects the short-circuit fault according to the voltage peak appearing at the gate pole, and the IGBT to be tested is turned off at the moment of 1.2 mu s. The maximum short-circuit current at this time is only 3600A.

And compare with current protection circuit and method based on short-circuit current information or gate pole information extraction, the utility model discloses detection circuitry is simple, and need not to adopt operational amplifier to carry out the parameter and draw, has reduced circuit cost and circuit area, and the commonality is better.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and equivalents or substitutions made on the basis of the above-mentioned technical solutions all belong to the scope of the present invention.

Claims

1. An IGBT short-circuit fault rapid protection circuit, comprising: a short circuit detection circuit, a gate logic circuit and an amplification circuit;

wherein: the gate logic circuit receives the switching signal V_pwmAnd a fault signal V_faultAnd outputs a control signal V to the amplifying circuit_p(ii) a Short-circuit detection circuit for detecting collector voltage V of IGBT to be detected_CEAnd gate voltage V_GAnd outputs a fault signal V to the gate logic circuit_fault(ii) a The amplifying circuit receives the control signal V_pAnd the output end of the power supply is connected with the gate pole of the IGBT to be tested.

2. The IGBT short-circuit fault fast protection circuit according to claim 1, wherein the short-circuit detection circuit comprises: a collector detection circuit, a gate detection circuit and a fault judgment circuit; wherein: collector voltage V detected by collector detection circuit at input end of collector detection circuit_CEThe output end of the fault judging circuit is connected with the first input end of the fault judging circuit; gate pole voltage V detected by input end of gate pole detection circuit_GOutput terminal and thereforeThe second input end of the fault judging circuit is connected with the first input end of the fault judging circuit; fault signal V output by fault judging circuit output end_fault。

3. The IGBT short-circuit fault fast protection circuit according to claim 2, wherein the collector detection circuit detects a collector voltage state in real time, comprising: diode D₁Diode D₂Diode D₃Resistance R₁Capacitor C₁Switch Q₁(ii) a Wherein: diode D₁The cathode of the IGBT is connected with the collector of the IGBT to be tested, the anode of the IGBT is connected with one end of a resistor R1, and a capacitor C₁One terminal of (D), diode D₂Anode of (2), diode D₃P-type switching tube Q₁Is connected to the other end of the resistor R1, and a diode D₂Cathode of (2) and P-type switching tube Q₁And a positive driving voltage V_CCConnecting; capacitor C₁Another terminal of (1) and a diode D₃The anode of (2) is grounded.

4. The IGBT short-circuit fault fast protection circuit according to claim 2, wherein the gate detection circuit employs a diode D₄Real-time detection of gate state, diode D₄The anode of the IGBT is connected with the gate pole of the IGBT to be tested.

5. The fast protection circuit for short-circuit fault of IGBT according to claim 2, wherein the fault determining circuit determines whether a short-circuit fault occurs according to the change state of the gate voltage and the collector voltage, and outputs a fault signal to the gate logic circuit, comprising: resistance R₂Resistance R₃Resistance R₄P-type switch tube Q₂Wherein: resistance R₂One end of the P-type switch tube Q₁Collector of (2), P-type switching tube Q₂Base electrode of (3), resistor R₃One end of the two ends are connected; resistance R₃Is connected with a reference voltage V at the other end_ref(ii) a Resistance R₂Another terminal of (1) and a diode D₄P-type switching tube Q₂Is connected with the emitting electrode of the P-type switch tubeQ₂Collector and resistor R₄Is connected to output a fault signal V_fault(ii) a Resistance R₄And the other end of the negative driving voltage V_EEAre connected.

6. The IGBT short-circuit fault rapid protection circuit of claim 3 or 5, characterized in that the P-type switch tube Q₁And Q₂And a power switching device with a faster switching speed, such as a BJT or a MOSFET, is adopted.

7. The IGBT short-circuit fault rapid protection circuit according to claim 1, wherein the gate logic circuit can be built by an AND gate or NAND gate chip, and can also be logically controlled by a digital chip FPGA/CPLD.

8. The IGBT short-circuit fault fast protection circuit of claim 2, wherein the gate-to-collector voltage detection circuit, reference voltage V_refThe value of (d) is between the Miller platform voltage and the positive drive voltage V of the IGBT_CCIn the meantime.