IGBT short circuit protection circuit and device

Abstract

The utility model discloses an IGBT short circuit protection circuit and device, a short circuit detection module of the circuit is respectively connected with a short circuit protection module and an IGBT, the short circuit protection module is connected with an IGBT gate driver, and the IGBT gate driver is connected with the IGBT. When an IGBT short circuit is detected by a short circuit detection module, a short circuit detection signal is output to a short circuit protection module; when the short circuit protection module receives a short circuit detection signal, a driving signal output to an IGBT gate driver is in short circuit with a negative power supply so as to carry out first-stage turn-off; and when the driving signal is in short circuit with the negative power supply, if the short-circuit protection module receives a short-circuit wave sealing signal, the PWM signal generating the driving signal is switched into a low-level signal so as to perform second-stage turn-off. According to the utility model, the IGBT is turned off in a two-stage turn-off mode, an active clamping circuit comprising a TVS tube does not need to be arranged, and the IGBT is prevented from being damaged due to overheating failure of the TVS tube.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to an IGBT short-circuit protection circuit and a device. Background Art

[0002] With the development of the power electronics industry, the use of insulated gate bipolar transistors (IGBTs) as power control devices in products such as energy storage converters, photovoltaic inverters, and wind power converters is becoming increasingly important. When an IGBT is overcurrent or short-circuited, the current flowing through the IGBT will increase rapidly. At this time, if the IGBT is quickly turned off, its current will drop very quickly. Due to the parasitic inductance inside the IGBT, a very high voltage spike will be generated between the CE of the IGBT. This voltage spike will far exceed the safe working area of ​​the IGBT, so the IGBT module will be damaged by overvoltage.

[0003] The existing IGBT short-circuit protection method is to add an active clamping circuit to the IGBT driver. During the IGBT short-circuit shutdown process, when the voltage spike between the CE of the IGBT exceeds the threshold value, the IGBT gate voltage can be raised by the transient voltage suppressor (TVS) tube in the active clamping circuit to briefly turn on the IGBT, thereby reducing the CE voltage spike. However, during the IGBT short-circuit shutdown process, if the voltage spike between the CE is large, the active clamping will work frequently, causing the TVS tube in the active clamping feedback circuit to overheat and fail, thereby causing damage to the IGBT.

[0004] The above contents are only used to assist in understanding the technical solution of the present utility model and do not constitute an admission that the above contents are prior art. Utility Model Content

[0005] The main purpose of the utility model is to provide an IGBT short-circuit protection circuit and device, aiming to solve the technical problem in the prior art that during the IGBT short-circuit shutdown process, if the voltage spike between CE is large, the active clamp will work frequently, causing the TVS tube in the active clamp feedback circuit to overheat and fail, thereby causing damage to the IGBT.

[0006] To achieve the above object, the utility model provides an IGBT short-circuit protection circuit, the circuit comprising: a short-circuit detection module and a short-circuit protection module;

[0007] The short-circuit detection module is connected to the short-circuit protection module and the IGBT respectively, the short-circuit protection module is connected to the IGBT gate driver, and the IGBT gate driver is connected to the IGBT;

[0008] The short-circuit detection module is used to output a short-circuit detection signal to the short-circuit protection module when detecting that the IGBT is short-circuited;

[0009] The short-circuit protection module is used to short-circuit the drive signal output to the IGBT gate drive with the negative power supply to perform a first-level shutdown when receiving the short-circuit detection signal;

[0010] The short-circuit protection module is also used for switching the PWM signal generating the driving signal to a low-level signal to perform a second-level shutdown when the driving signal is short-circuited with the negative power supply and a short-circuit wave blocking signal is received.

[0011] Optionally, the short circuit protection module includes: a first switch unit and a second switch unit;

[0012] The first switch unit is respectively connected to the short-circuit detection module, the second switch unit, the positive power supply and the negative power supply, and the second switch unit is respectively connected to the positive power supply, the negative power supply, the isolation optocoupler and the IGBT gate driver;

[0013] The first switch unit is used to connect the positive power supply to the control end of the second switch unit when receiving the short-circuit detection signal;

[0014] The second switch unit is used to connect the output end of the isolation optocoupler to the negative power supply when the positive power supply is connected to the control end of the second switch unit, so that the driving signal output by the isolation optocoupler to the IGBT gate drive is short-circuited with the negative power supply.

[0015] Optionally, the first switch unit includes: a first transistor, a first resistor and a second resistor;

[0016] The second switch unit includes: a second transistor and a third resistor;

[0017] The base of the first transistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the short-circuit detection module, the collector of the first transistor is respectively connected to the first end of the second resistor and the base of the second transistor, the second end of the second resistor is connected to the positive power supply, the emitter of the first transistor is connected to the negative power supply, the collector of the second transistor is connected to the first end of the third resistor, the second end of the third resistor is respectively connected to the output end of the isolation optocoupler and the IGBT gate drive, and the emitter of the second transistor is connected to the negative power supply.

[0018] Optionally, the short-circuit protection module further includes: a short-circuit wave-sealing unit;

[0019] The short-circuit wave-sealing unit is respectively connected to the input end of the isolation optical coupler and the wave-sealing signal generator;

[0020] The short-circuit wave-encapsulation unit is used to detect whether the short-circuit wave-encapsulation signal output by the wave-encapsulation signal generator is received when the driving signal is short-circuited with the negative power supply;

[0021] The short-circuit wave-encapsulation unit is used to switch the PWM signal input to the isolation optical coupler to a low-level signal when receiving the short-circuit wave-encapsulation signal output by the wave-encapsulation signal generator, so as to perform a second-level shutdown.

[0022] Optionally, the short-circuit wave-sealing unit comprises: a first diode and a fourth resistor;

[0023] The anode of the first diode is connected to the anode of the light emitting diode of the isolation optocoupler, the cathode of the first diode is connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the sealing wave signal generator.

[0024] Optionally, the short circuit detection module includes: a third switch unit and a short circuit detection unit;

[0025] The third switch unit is connected to the IGBT, the positive power supply and the short-circuit detection unit respectively, and the short-circuit detection unit is connected to the positive power supply, the negative power supply and the short-circuit protection module respectively;

[0026] The third switch unit is used to disconnect the positive power supply from the short-circuit detection unit when the collector and emitter of the IGBT are in an off state;

[0027] The short-circuit detection unit is further used to trigger the short-circuit detection signal of the IGBT short circuit when the positive power supply is disconnected, and output the short-circuit detection signal to the short-circuit protection module.

[0028] Optionally, the third switch unit is further configured to connect the positive power supply to the short-circuit detection unit when it is detected that the voltage between the gate and the emitter of the IGBT is a negative voltage;

[0029] The short-circuit detection unit is further used to conduct a short-circuit detection loop between the positive power supply and the negative power supply when the positive power supply is connected;

[0030] The short-circuit detection unit is also used to trigger a disconnection signal for normal shutdown of the IGBT when the short-circuit detection loop is turned on.

[0031] Optionally, the third switch unit is further used to disconnect the positive power supply from the short-circuit detection unit when the collector and emitter of the IGBT are in an off state, so as to disconnect the short-circuit detection loop;

[0032] The short-circuit detection unit is further used to trigger the short-circuit detection signal of the IGBT short circuit when the short-circuit detection loop is disconnected, and output the short-circuit detection signal to the short-circuit protection module.

[0033] Optionally, the third switch unit includes: a first MOS tube, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a second diode;

[0034] The gate of the first MOS tube is grounded;

[0035] The drain of the first MOS tube is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is respectively connected to the first end of the seventh resistor, the first end of the eighth resistor and the short-circuit detection unit, the second end of the seventh resistor is connected to the positive power supply, the second end of the eighth resistor is connected to the anode of the second diode, and the cathode of the second diode and the source of the first MOS tube are both connected to the IGBT.

[0036] Optionally, the short circuit detection unit includes: a third transistor, a ninth resistor, a tenth resistor and an eleventh resistor;

[0037] The base of the third transistor is connected to the second end of the sixth resistor and the first end of the eighth resistor respectively;

[0038] The emitter of the third triode is connected to the positive power supply;

[0039] The collector of the third triode is connected to the first end of the ninth resistor and the first end of the tenth resistor respectively, the second end of the ninth resistor and the second end of the tenth resistor are both connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the negative power supply;

[0040] The disconnection signal is triggered when there is a voltage difference between the first end and the second end of the eleventh resistor, and the short-circuit detection signal is triggered when there is no voltage difference between the first end and the second end of the eleventh resistor.

[0041] In addition, to achieve the above-mentioned purpose, the utility model also proposes an IGBT short-circuit protection device, which includes the IGBT short-circuit protection circuit as described above.

[0042] The utility model provides an IGBT short-circuit protection circuit and device, the circuit includes: a short-circuit detection module and a short-circuit protection module; the short-circuit detection module is respectively connected to the short-circuit protection module and the IGBT, the short-circuit protection module is connected to the IGBT gate driver, and the IGBT gate driver is connected to the IGBT. When the short-circuit detection module of the utility model detects that the IGBT is short-circuited, it outputs a short-circuit detection signal to the short-circuit protection module; when the short-circuit protection module receives the short-circuit detection signal, it short-circuits the drive signal output to the IGBT gate driver with the negative power supply to perform the first-level shutdown; when the drive signal is short-circuited with the negative power supply, if the short-circuit protection module receives a short-circuit wave blocking signal, it switches the PWM signal that generates the drive signal to a low-level signal to perform the second-level shutdown. When the IGBT is short-circuited, the circuit of the utility model turns off the IGBT through a two-stage turn-off method consisting of a first-stage turn-off and a second-stage turn-off, without the need to set an active clamping circuit including a TVS tube, effectively avoiding damage to the IGBT due to overheating and failure of the TVS tube when the voltage spike between CE is large, thereby improving the safety of the IGBT turn-off. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic structural diagram of a first embodiment of an IGBT short-circuit protection circuit of the utility model;

[0044] Figure 2 This is a schematic diagram of the peripheral structure of the IGBT in the first embodiment of the IGBT short-circuit protection circuit of the utility model;

[0045] Figure 3 It is a structural schematic diagram of a second embodiment of the IGBT short-circuit protection circuit of the utility model;

[0046] Figure 4 This is a circuit schematic diagram of the first switch unit and the second switch unit in the second embodiment of the IGBT short-circuit protection circuit of the utility model;

[0047] Figure 5 This is a circuit schematic diagram of a short-circuit wave blocking unit in the second embodiment of the IGBT short-circuit protection circuit of the utility model;

[0048] Figure 6 It is a structural schematic diagram of a third embodiment of the IGBT short-circuit protection circuit of the utility model;

[0049] Figure 7 This is a circuit schematic diagram of the third embodiment of the IGBT short-circuit protection circuit of the utility model.

[0050] Description of Figure Numbers:

[0051] Label name Label name Q1 The first transistor Q2 The second transistor Q3 The first MOS tube Q4 The third transistor D1 The first diode D2 The second diode R1 First resistor R2 Second resistor R3 The third resistor R4 The fourth resistor R5 Fifth resistor R6 The sixth resistor R7 Seventh resistor R8 Eighth resistor R9 Ninth resistor R10 Tenth resistor R11 The eleventh resistor

[0052] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0054] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0055] It should be noted that the descriptions of "first", "second", etc. in the embodiments of the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0056] Reference Figure 1 , Figure 1 It is a structural schematic diagram of the first embodiment of the IGBT short-circuit protection circuit of the utility model.

[0057] like Figure 1 As shown, in this embodiment, the IGBT short-circuit protection circuit includes: a short-circuit detection module 100 and a short-circuit protection module 200 .

[0058] The short-circuit detection module 100 is connected to the short-circuit protection module 200 and the IGBT respectively. The short-circuit protection module 200 is connected to the IGBT gate driver 300 , and the IGBT gate driver 300 is connected to the IGBT.

[0059] The short-circuit detection module 100 is used to output a short-circuit detection signal to the short-circuit protection module 200 when a short circuit of the IGBT is detected.

[0060] In a specific implementation, when a short circuit occurs in the IGBT, the Vce of the IGBT is in an off state, that is, the collector and emitter of the IGBT are disconnected. When the short circuit detection module 100 detects that the Vce of the IGBT is in an off state, it can generate a short circuit detection signal representing the IGBT short circuit fault to the short circuit protection module 200.

[0061] In addition, the short-circuit detection module 100 can also send the short-circuit detection signal to a complex programmable logic device (CPLD). After the CPLD conditions the short-circuit detection signal, it generates a short-circuit fault signal and feeds back the short-circuit fault signal to the user to remind the user that a short-circuit fault occurs in the IGBT.

[0062] The short-circuit protection module 200 is used to short-circuit the drive signal output to the IGBT gate driver 300 with the negative power supply when receiving the short-circuit detection signal, so as to perform a first-level shutdown.

[0063] It should be noted that the on and off of the IGBT is controlled by the voltage on its gate (G pole). When a positive voltage is applied to the gate, the IGBT will be turned on, allowing current to pass; and when the gate voltage is removed or becomes a negative voltage, the IGBT will be turned off, preventing current from passing. The above-mentioned IGBT gate driver 300 is a circuit that generates a gate voltage to control the IGBT.

[0064] like Figure 2 As shown, Figure 2 This is a schematic diagram of the peripheral structure of the IGBT in the first embodiment of the IGBT short-circuit protection circuit of the utility model. In addition to the IGBT short-circuit protection circuit, the above-mentioned IGBT peripheral circuit also includes a level conversion circuit, a CPLD, an isolation optocoupler, a secondary side signal processing circuit and a fault signal isolation optocoupler.

[0065] Specifically, the power supply is connected to the isolated power supply, and the isolated power supply provides power for the secondary side signal processing circuit. The input initial PWM signal is level-converted by the level conversion circuit and then input into the CPLD for signal conditioning. The conditioned PWM signal is level-converted again by the level conversion circuit and then enters the isolation optocoupler 400. The isolation optocoupler 400 outputs a drive signal to the secondary side signal processing circuit for processing. The processed drive signal is input into the IGBT gate driver 300. The IGBT gate driver 300 converts the processed drive signal into a gate voltage for driving the IGBT, and applies the gate voltage to the gate of the IGBT to achieve precise control of the IGBT.

[0066] The short-circuit detection module 100 performs short-circuit detection on the IGBT, and outputs a short-circuit detection signal to the short-circuit protection module 200 when the IGBT is short-circuited. In addition, the short-circuit detection module 100 can send the short-circuit detection signal to the CPLD through the fault signal isolation optocoupler. After the CPLD conditions the short-circuit detection signal, it inputs the conditioned signal into the level conversion signal for level conversion, and outputs a short-circuit fault signal.

[0067] It should be noted that in order to facilitate understanding, Figure 2 The circuit protection module 200 is shown separately from the secondary signal processing circuit. In actual application, the short circuit protection module 200 can be arranged in the secondary signal processing circuit to become a part of the secondary signal processing circuit.

[0068] In a specific implementation, when the short-circuit protection module 200 receives the short-circuit detection signal output by the short-circuit detection module 100, the output end of the isolation optocoupler 400 can be short-circuited with the negative power supply, so that the drive signal output by the isolation optocoupler 400 to the secondary signal processing circuit is short-circuited with the negative power supply. Since the drive signal is short-circuited with the negative power supply, the secondary signal processing circuit has no corresponding signal input, and the IGBT gate driver 200 cannot generate a gate voltage to drive the IGBT, thereby realizing the first-level shutdown of the IGBT.

[0069] The short-circuit protection module 200 is also used for switching the driving signal to a low-level signal to perform a second-level shutdown when the driving signal is short-circuited with the negative power supply and a short-circuit wave blocking signal is received.

[0070] It should be noted that the short-circuit blocking signal may be a signal for stopping the generation of the PWM waveform or setting the PWM signal to a low level.

[0071] In a specific implementation, when the IGBT is turned off by disconnecting the first-level turn-off method of the driving signal, a voltage spike will be generated between the CE (collector and emitter) of the IGBT, and the voltage spike will far exceed the safe working area of ​​the IGBT, causing damage to the IGBT. Therefore, the short-circuit protection module 200 can be provided with a device that generates a short-circuit wave-sealing signal at the input end of the isolation optocoupler 400 (i.e., where the PWM signal is received). When the driving signal is short-circuited to the negative power supply for a set time or the short-circuit time of the IGBT reaches a set time (the set time can be determined according to demand), the device can be triggered to generate a short-circuit wave-sealing signal, so that the PWM signal that generates the driving signal is switched to a low-level signal through the short-circuit wave-sealing signal, thereby pulling down the PWM signal, that is, switching the level of the PWM signal to 0 level, so that the isolation optocoupler 400 has no PWM signal input, and then no driving signal is generated, thereby shutting down the IGBT at the source, avoiding the voltage spike between the CE of the IGBT causing damage to the IGBT. Furthermore, the above two-stage shutdown method does not involve an active clamping circuit formed by a TVS tube, and the TVS tube will not overheat and fail, resulting in damage to the IGBT. In addition, the above two-stage shutdown method has a fast response and can shut down the IGBT in a timely, safe and effective manner.

[0072] The IGBT short-circuit protection circuit of this embodiment includes: a short-circuit detection module and a short-circuit protection module; the short-circuit detection module is connected to the short-circuit protection module and the IGBT respectively, the short-circuit protection module is connected to the IGBT gate driver, and the IGBT gate driver is connected to the IGBT. When the short-circuit detection module of this embodiment detects that the IGBT is short-circuited, it outputs a short-circuit detection signal to the short-circuit protection module; when the short-circuit protection module receives the short-circuit detection signal, the driving signal output to the IGBT gate driver is short-circuited with the negative power supply to perform the first-level shutdown; when the driving signal is short-circuited with the negative power supply, if the short-circuit protection module receives a short-circuit wave blocking signal, the PWM signal generating the driving signal is switched to a low-level signal to perform the second-level shutdown. When the IGBT is short-circuited, the above-mentioned circuit of this embodiment shuts down the IGBT through a two-level shutdown method consisting of the first-level shutdown and the second-level shutdown, without the need to set an active clamping circuit including a TVS tube, effectively avoiding the damage of the IGBT caused by the overheating failure of the TVS tube when the voltage spike between CE is large, thereby improving the safety of the IGBT shutdown.

[0073] Figure 3 It is a structural schematic diagram of the second embodiment of the IGBT short-circuit protection circuit of the utility model.

[0074] Based on the above first embodiment, in this embodiment, the short circuit protection module 200 includes: a first switch unit 201 and a second switch unit 202 .

[0075] The first switch unit 201 is respectively connected to the short circuit detection module 100 , the second switch unit 202 , the positive power supply and the negative power supply, and the second switch unit 202 is respectively connected to the positive power supply, the negative power supply, the isolation optocoupler 400 and the IGBT gate driver 300 .

[0076] The first switch unit 201 is used to connect the positive power supply to the control end of the second switch unit 202 when receiving the short-circuit detection signal.

[0077] The second switch unit 202 is used to connect the output end of the isolation optocoupler 400 to the negative power supply when the positive power supply is connected to the control end of the second switch unit, so that the drive signal output by the isolation optocoupler 400 to the IGBT gate driver 300 is short-circuited with the negative power supply.

[0078] like Figure 4 As shown, Figure 4 This is a circuit schematic diagram of the first switch unit and the second switch unit in the second embodiment of the IGBT short-circuit protection circuit of the utility model. Figure 4 In the embodiment, the first switch unit 201 includes: a first transistor Q1, a first resistor R1 and a second resistor R2.

[0079] The second switch unit 202 includes a second transistor Q2 and a third resistor R3.

[0080] The base of the first transistor Q1 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the short-circuit detection module 100, the collector of the first transistor Q1 is respectively connected to the first end of the second resistor R2 and the base of the second transistor Q2, the second end of the second resistor R2 is connected to the positive power supply, the emitter of the first transistor Q1 is connected to the negative power supply, the collector of the second transistor Q2 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is respectively connected to the output end of the isolation optocoupler 400 and the IGBT gate driver 300, and the emitter of the second transistor Q2 is connected to the negative power supply.

[0081] In a specific implementation, the first transistor Q1 and the second transistor Q2 may be NPN transistors. When the short-circuit detection module 100 detects that the IGBT is not short-circuited, it may send a high-level signal to the base of the first transistor Q1 to close the first transistor Q1 and turn on the loop formed by the positive power supply, the second resistor R2 and the negative power supply. At this time, the second transistor Q2 is in a disconnected state. When the IGBT is short-circuited, the short-circuit detection module 100 can output a low-level short-circuit detection signal to the base of the first transistor Q1, so that the first transistor Q1 is disconnected, and the positive power supply is connected to the base of the second transistor Q2 through the second resistor R2. At this time, the positive power supply can output a high-level drive signal to the base of the second transistor Q2 through the second resistor R2, so that the second transistor Q2 is closed, and the output end of the isolation optocoupler 400 is connected to the negative power supply through the third resistor R3, so that the drive signal output by the isolation optocoupler 400 to the IGBT gate driver 300 is short-circuited with the negative power supply, thereby accurately realizing the first-level shutdown.

[0082] Further, in this embodiment, reference Figure 3 In this embodiment, the short circuit protection module 200 further includes: a short circuit wave blocking unit 203.

[0083] The short-circuit wave-encapsulation unit 203 is connected to the input end of the isolation optical coupler 400 and the wave-encapsulation signal generator 204 respectively.

[0084] The short-circuit wave-encapsulation unit 203 is used to detect whether the short-circuit wave-encapsulation signal output by the wave-encapsulation signal generator 204 is received when the driving signal is short-circuited with the negative power supply.

[0085] The short-circuit encapsulation unit 203 is used to switch the PWM signal input to the isolation optical coupler 400 to a low-level signal when receiving the short-circuit encapsulation signal output by the encapsulation signal generator 204, so as to perform a second-level shutdown.

[0086] like Figure 5 As shown, Figure 5 This is a circuit schematic diagram of a short-circuit wave blocking unit in the second embodiment of the IGBT short-circuit protection circuit of the utility model. Figure 5 In the embodiment, the short-circuit wave-encapsulating unit 203 includes: a first diode D2 and a fourth resistor R4.

[0087] The anode of the first diode D2 is connected to the anode of the light emitting diode of the isolation optocoupler 400 , the cathode of the first diode D1 is connected to the first end of the fourth resistor R4 , and the second end of the fourth resistor R4 is connected to the envelope signal generator 204 .

[0088] In a specific implementation, during the short-circuit process between the driving signal and the negative power supply, the sealing signal generator 204 can generate a short-circuit sealing signal after a certain delay, and output the short-circuit sealing signal to the anode of the light-emitting diode in the isolation optocoupler 400 through the fourth resistor R4 and the first diode D1, so as to switch the PWM signal input to the isolation optocoupler 400 to a low-level signal through the short-circuit sealing signal, thereby pulling down the PWM signal, and accurately realizing the second-level shutdown, ensuring that when the IGBT is short-circuited, it can accurately and safely realize the shutdown under the action of the first-level shutdown and the second-level shutdown, thereby improving the safety of the IGBT shutdown.

[0089] refer to Figure 6 , Figure 6 It is a schematic structural diagram of a third embodiment of an IGBT short-circuit protection circuit of the utility model.

[0090] Based on the above first embodiment, in this embodiment, the short circuit detection module 100 includes: a third switch unit 101 and a short circuit detection unit 102 .

[0091] The third switch unit 101 is connected to the IGBT, the positive power supply and the short-circuit detection unit 102 respectively, and the short-circuit detection unit 102 is connected to the positive power supply, the negative power supply and the short-circuit protection module 200 respectively.

[0092] The third switch unit 101 is used to disconnect the positive power supply from the short-circuit detection unit 102 when the collector and emitter of the IGBT are in an off state, so as to disconnect the short-circuit detection loop.

[0093] like Figure 7 As shown, Figure 7 This is a circuit schematic diagram of the third embodiment of the IGBT short-circuit protection circuit of the utility model. Figure 7 In the embodiment, the third switch unit includes: a first MOS tube Q3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a second diode D2; the short circuit detection unit 102 includes: a third transistor D3, a ninth resistor R9, a tenth resistor R10 and an eleventh resistor R11.

[0094] The gate of the first MOS tube Q3 is grounded, the drain of the first MOS tube Q3 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is respectively connected to the first end of the seventh resistor R7, the first end of the eighth resistor R8 and the short-circuit detection unit 102, the second end of the seventh resistor R7 is connected to the positive power supply, the second end of the eighth resistor R8 is connected to the anode of the second diode D2, and the cathode of the second diode D2 and the source of the first MOS tube Q3 are both connected to the IGBT.

[0095] The base of the third transistor Q4 is respectively connected to the second end of the sixth resistor R6 and the first end of the eighth resistor R8, the emitter of the third transistor Q4 is connected to the positive power supply, the collector of the third transistor Q4 is respectively connected to the first end of the ninth resistor R9 and the first end of the tenth resistor R10, the second end of the ninth resistor R9 and the second end of the tenth resistor R10 are both connected to the first end of the eleventh resistor R11, and the second end of the eleventh resistor R11 is connected to the negative power supply.

[0096] In a specific implementation, the first MOS tube Q3 can be an NMOS tube. When the IGBT is short-circuited, the collector and emitter of the IGBT are in an off state, that is, IGBTVce is in a disconnected state, and the loop formed by the positive power supply, the seventh resistor R7, the eighth resistor R8, the second diode D2 and the IGBT is disconnected, so that the base of the third triode Q4 cannot receive the corresponding trigger signal and is disconnected, so that the short-circuit detection loop is in a disconnected state.

[0097] The short-circuit detection unit 102 is used to trigger the short-circuit detection signal of the IGBT short circuit when the short-circuit detection loop is disconnected, and output the short-circuit detection signal to the short-circuit protection module 200 .

[0098] In a specific implementation, when the short-circuit detection loop formed by the positive power supply, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 and the negative power supply is disconnected, there is no voltage difference across the eleventh resistor R11. At this time, the eleventh resistor R11 can trigger a short-circuit detection signal representing an IGBT short circuit.

[0099] It should be understood that, when the IGBT is normally turned off, the circuit formed by the positive power supply, the seventh resistor R7, the eighth resistor R8, the second diode D2 and the IGBT is turned on, so that the third transistor Q4 is closed, the above short-circuit detection circuit is turned on, and then the disconnection signal is triggered across the eleventh resistor R11. When the IGBT is short-circuited, no matter whether the driving Vge is a positive voltage or a negative voltage, the circuit formed by the positive power supply, the seventh resistor R7, the eighth resistor R8, the second diode D2 and the IGBT is disconnected.

[0100] Furthermore, in this embodiment, the third switch unit 101 is also used to connect the positive power supply to the short-circuit detection unit 102 when it is detected that the voltage between the gate and the emitter of the IGBT is a negative voltage, so that the positive power supply outputs a trigger signal to the short-circuit detection unit 102.

[0101] In a specific implementation, when the IGBT is normally turned off, the voltage between the gate and emitter of the IGBT (i.e., the driving Vge) is a negative voltage, and the source of the first MOS tube Q3 is connected to the negative voltage, so that the first MOS tube Q3 is turned on, and the loop composed of the positive power supply, the seventh resistor R7, the sixth resistor R6, the fifth resistor R5 and the IGBT is turned on. The positive power supply can be connected to the third transistor Q4 of the short-circuit detection unit 102 through the seventh resistor R7, so that the positive power supply outputs a trigger signal to the third transistor Q4 through the seventh resistor R7.

[0102] The short circuit detection unit 102 is further configured to switch on a short circuit detection loop between the positive power supply and the negative power supply when receiving the trigger signal.

[0103] In a specific implementation, the third transistor Q4 can be a PNP tube, the emitter of the third transistor Q4 is directly connected to the positive power supply, and receives the power supply voltage provided by the positive power supply, and the voltage of the trigger signal received by the base of the third transistor Q4 is the power supply voltage obtained by dividing the seventh resistor R7, the sixth resistor R6 and the fifth resistor R5. Therefore, the emitter voltage of the third transistor Q4 is higher than the base voltage, so that the third transistor Q4 is closed, and the short-circuit detection loop composed of the positive power supply, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 and the negative power supply is turned on.

[0104] The short-circuit detection unit 102 is further configured to trigger a disconnection signal for normal shutdown of the IGBT when the short-circuit detection loop is turned on.

[0105] In a specific implementation, the eleventh resistor R11 can be used as a short-circuit detection device. When the short-circuit detection loop is turned on, there is a voltage difference across the eleventh resistor R11. Based on the voltage difference, a disconnection signal for normal shutdown of the IGBT can be triggered.

[0106] In addition, when the IGBT is normally turned on, the voltage between the gate and emitter of the IGBT (i.e., the driving Vge) is a positive voltage, so that the first MOS tube Q3 is disconnected, and the loop composed of the positive power supply, the seventh resistor R7, the sixth resistor R6, the fifth resistor R5 and the IGBT is in a disconnected state. When the IGBT is normally turned on, IGBTVce is in a turned-on state. Therefore, the loop composed of the positive power supply, the seventh resistor R7, the eighth resistor R8, the second diode D2 and the IGBT is turned on, so that the base of the third triode Q4 can receive the corresponding trigger signal and close, turning on the above-mentioned short-circuit detection circuit, and there is a voltage difference across the eleventh resistor R11 to trigger the normal signal of the normal conduction of the IGBT, thereby avoiding misjudging the normal conduction of the IGBT as a short circuit.

[0107] In this embodiment, the positive power supply is disconnected from the short-circuit detection unit by the third switch unit when the collector and emitter of the IGBT are in the off state; the short-circuit detection unit triggers the short-circuit detection signal of the IGBT short circuit when the positive power supply is disconnected, and outputs the short-circuit detection signal to the short-circuit protection module; the third switch unit connects the positive power supply to the short-circuit detection unit when it detects that the voltage between the gate and the emitter of the IGBT is a negative voltage; the short-circuit detection unit turns on the short-circuit detection circuit between the positive power supply and the negative power supply when the positive power supply is connected; the short-circuit detection unit triggers the disconnection signal of the normal shutdown of the IGBT when the short-circuit detection circuit is turned on. Based on this, the short-circuit and normal shutdown situations of the IGBT can be accurately distinguished, effectively improving the accuracy of short-circuit detection.

[0108] In addition, an embodiment of the utility model further provides an IGBT short-circuit protection device, which includes the IGBT short-circuit protection circuit described above.

[0109] Other embodiments or specific implementations of the stream data writing device of the present invention can refer to the above-mentioned alarm circuit embodiment, which will not be described in detail here.

[0110] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0111] The serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0112] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An IGBT short-circuit protection circuit, characterized in that: The circuit comprises: a short circuit detection module and a short circuit protection module; The short-circuit detection module is connected to the short-circuit protection module and the IGBT respectively, the short-circuit protection module is connected to the IGBT gate driver, and the IGBT gate driver is connected to the IGBT; The short-circuit detection module is used to output a short-circuit detection signal to the short-circuit protection module when detecting that the IGBT is short-circuited; The short-circuit protection module is used to short-circuit the drive signal output to the IGBT gate drive with the negative power supply to perform a first-level shutdown when receiving the short-circuit detection signal; The short-circuit protection module is also used to switch the PWM signal used to generate the drive signal to a low-level signal to perform a second-level shutdown if a short-circuit wave blocking signal is received after the drive signal is short-circuited with the negative power supply.

2. The IGBT short-circuit protection circuit according to claim 1, characterized in that: The short circuit protection module comprises: a first switch unit and a second switch unit; The first switch unit is respectively connected to the short-circuit detection module, the second switch unit, the positive power supply and the negative power supply, and the second switch unit is respectively connected to the positive power supply, the negative power supply, the isolation optocoupler and the IGBT gate driver; The first switch unit is used to connect the positive power supply to the control end of the second switch unit when receiving the short-circuit detection signal; The second switch unit is used to connect the output end of the isolation optocoupler to the negative power supply when the positive power supply is connected to the control end of the second switch unit, so that the driving signal output by the isolation optocoupler to the IGBT gate drive is short-circuited with the negative power supply.

3. The IGBT short-circuit protection circuit according to claim 2, characterized in that: The first switch unit includes: a first transistor, a first resistor and a second resistor; The second switch unit includes: a second transistor and a third resistor; The base of the first transistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the short-circuit detection module, the collector of the first transistor is respectively connected to the first end of the second resistor and the base of the second transistor, the second end of the second resistor is connected to the positive power supply, the emitter of the first transistor is connected to the negative power supply, the collector of the second transistor is connected to the first end of the third resistor, the second end of the third resistor is respectively connected to the output end of the isolation optocoupler and the IGBT gate drive, and the emitter of the second transistor is connected to the negative power supply.

4. The IGBT short-circuit protection circuit according to claim 2, characterized in that: The short circuit protection module further comprises: a short circuit wave blocking unit; The short-circuit wave-sealing unit is respectively connected to the input end of the isolation optical coupler and the wave-sealing signal generator; The short-circuit wave-encapsulation unit is used to detect whether the short-circuit wave-encapsulation signal output by the wave-encapsulation signal generator is received when the driving signal is short-circuited with the negative power supply; The short-circuit wave-encapsulation unit is used to switch the PWM signal input to the isolation optical coupler to a low-level signal when receiving the short-circuit wave-encapsulation signal output by the wave-encapsulation signal generator, so as to perform a second-level shutdown.

5. The IGBT short-circuit protection circuit according to claim 4, characterized in that: The short-circuit wave-sealing unit comprises: a first diode and a fourth resistor; The anode of the first diode is connected to the anode of the light emitting diode of the isolation optocoupler, the cathode of the first diode is connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the sealing signal generator.

6. The IGBT short-circuit protection circuit according to claim 1, characterized in that: The short circuit detection module comprises: a third switch unit and a short circuit detection unit; The third switch unit is connected to the IGBT, the positive power supply and the short-circuit detection unit respectively, and the short-circuit detection unit is connected to the positive power supply, the negative power supply and the short-circuit protection module respectively; The third switch unit is used to disconnect the positive power supply from the short-circuit detection unit when the collector and emitter of the IGBT are in an off state; The short-circuit detection unit is further used to trigger the short-circuit detection signal of the IGBT short circuit when the positive power supply is disconnected, and output the short-circuit detection signal to the short-circuit protection module.

7. The IGBT short-circuit protection circuit according to claim 6, characterized in that: The third switch unit is further used to connect the positive power supply to the short-circuit detection unit when it is detected that the voltage between the gate and the emitter of the IGBT is a negative voltage; The short-circuit detection unit is further used to conduct a short-circuit detection loop between the positive power supply and the negative power supply when the positive power supply is connected; The short-circuit detection unit is also used to trigger a disconnection signal for normal shutdown of the IGBT when the short-circuit detection loop is turned on.

8. The IGBT short-circuit protection circuit according to claim 7, characterized in that: The third switch unit includes: a first MOS tube, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a second diode; The gate of the first MOS tube is grounded; The drain of the first MOS tube is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is respectively connected to the first end of the seventh resistor, the first end of the eighth resistor and the short-circuit detection unit, the second end of the seventh resistor is connected to the positive power supply, the second end of the eighth resistor is connected to the anode of the second diode, and the cathode of the second diode and the source of the first MOS tube are both connected to the IGBT.

9. The IGBT short-circuit protection circuit according to claim 8, characterized in that: The short circuit detection unit includes: a third transistor, a ninth resistor, a tenth resistor and an eleventh resistor; The base of the third transistor is connected to the second end of the sixth resistor and the first end of the eighth resistor respectively; The emitter of the third triode is connected to the positive power supply; The collector of the third triode is connected to the first end of the ninth resistor and the first end of the tenth resistor respectively, the second end of the ninth resistor and the second end of the tenth resistor are both connected to the first end of the eleventh resistor, and the second end of the eleventh resistor is connected to the negative power supply; The disconnection signal is triggered when there is a voltage difference between the first end and the second end of the eleventh resistor, and the short-circuit detection signal is triggered when there is no voltage difference between the first end and the second end of the eleventh resistor.

10. An IGBT short-circuit protection device, characterized in that: The device comprises the IGBT short-circuit protection circuit according to any one of claims 1 to 9.

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