Short-circuit protection circuit and motor controller

Abstract

An embodiment of the present invention discloses a short - circuit protection circuit and a motor controller. The short - circuit protection circuit includes a short - circuit detection module, a soft - turn - off circuit switching module, and a drive current amplification module; the input end of the short - circuit detection module is connected to the first pole of the IGBT, the output end of the short - circuit detection module is connected to the over - current detection end of the drive module, and the short - circuit detection module is used to detect the current of the first pole of the IGBT; the soft - turn - off circuit switching module includes a first switching transistor, a first resistor is connected in parallel between the first end and the second end of the first switching transistor, the first end of the first switching transistor is connected to the output end of the drive module, and the second end of the first switching transistor is connected to the input end of the drive current amplification module; the control end of the first switching transistor is connected to the over - current detection end through a switching circuit; the soft - turn - off circuit switching module is used to switch the turn - off circuit of the IGBT through the first switching transistor according to the detection signal of the over - current detection end; the output end of the drive current amplification module is connected to the gate of the IGBT.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of power supply technology, and in particular, to a short-circuit protection circuit and a motor controller. Background Art

[0002] Motor controllers usually use a two-level three-phase inverter topology, which involves the switching control of 3 bridge arms and 6 IGBTs. In the life cycle, the situation of direct short circuit between the upper and lower bridges may occur. Limited by the short-circuit time allowed by the IGBT (generally, the allowed short-circuit time is 10 μs, and exceeding this time may cause damage to the IGBT), when a short-circuit occurs, it is necessary to detect the short-circuit situation and cut off the short-circuit path within an extremely short time. The short-circuit current can reach 10 times the nominal current of the IGBT. If the turn-off circuit in normal operation is directly used for turn-off, the too high current change rate will directly cause the IGBT to fail due to overvoltage. Summary of the Invention

[0003] Embodiments of the present invention provide a short-circuit protection circuit and a motor controller to protect IGBT devices.

[0004] In a first aspect, an embodiment of the present invention provides a short-circuit protection circuit applied to an IGBT drive circuit. The IGBT drive circuit includes an IGBT and a drive module. The short-circuit protection circuit includes: a short-circuit detection module, a soft turn-off circuit switching module, and a drive current amplification module;

[0005] The input end of the short-circuit detection module is connected to the first pole of the IGBT, and the output end of the short-circuit detection module is connected to the overcurrent detection end of the drive module. The short-circuit detection module is used to detect the first-pole current of the IGBT;

[0006] The soft turn-off circuit switching module includes a first switching tube. A first resistor is connected in parallel between the first end and the second end of the first switching tube. The first end of the first switching tube is connected to the output end of the drive module, and the second end of the first switching tube is connected to the input end of the drive current amplification module; the control end of the first switching tube is connected to the overcurrent detection end of the drive module through a switching circuit; the soft turn-off circuit switching module is used to switch the turn-off circuit of the IGBT through the first switching tube according to the detection signal at the overcurrent detection end of the drive module;

[0007] The output end of the drive current amplification module is connected to the gate of the IGBT, and the drive current amplification module is used to amplify the output signal of the drive module and then drive the gate of the IGBT.

[0008] Optionally, the switching circuit includes a second switching tube, a voltage regulation module, and a third switching tube;

[0009] The control terminal of the second switching transistor is connected to the overcurrent detection terminal of the driving module. The first terminal of the second switching transistor is connected to the control terminal of the voltage regulation module, and the second terminal of the second switching transistor is grounded.

[0010] The input terminal of the voltage regulation module is connected to a first set voltage, and the output terminal of the voltage regulation module is connected to the control terminal of the third switching transistor.

[0011] The control terminal of the third switching transistor is further connected to the first terminal of a second resistor, and the second terminal of the second resistor is connected to the first set voltage. The first terminal of the third switching transistor is connected to the first set voltage, and the second terminal of the third switching transistor is connected to the control terminal of the first switching transistor.

[0012] Optionally, the voltage regulation module includes a first triode. The base of the first triode is connected to the first terminal of a third resistor, and the second terminal of the third resistor serves as the control terminal of the voltage regulation module. The emitter of the first triode serves as the input terminal of the voltage regulation module. The collector of the first triode is respectively connected to the first terminal of a fourth resistor and the first terminal of a fifth resistor. The second terminal of the fourth resistor is grounded, and the second terminal of the fifth resistor serves as the output terminal of the voltage regulation module.

[0013] Optionally, the switching circuit further includes a voltage dividing circuit. The input terminal of the voltage dividing circuit is connected to the overcurrent detection terminal of the driving module, and the output terminal of the voltage dividing circuit is connected to the control terminal of the second switching transistor.

[0014] Optionally, the voltage dividing circuit includes an eighth resistor and a ninth resistor. The first terminal of the eighth resistor and the first terminal of the ninth resistor respectively serve as the input terminal and the output terminal of the voltage dividing circuit. The second terminal of the eighth resistor is connected to the first terminal of the ninth resistor, and the second terminal of the ninth resistor is grounded.

[0015] Optionally, the switching circuit further includes a sixth resistor, a seventh resistor, and a first capacitor.

[0016] The first terminal of the sixth resistor is connected to the first terminal of the third switching transistor, and the second terminal of the sixth resistor is connected to the control terminal of the first switching transistor.

[0017] The first terminal of the seventh resistor is connected to the first terminal of the first switching transistor, and the second terminal of the seventh resistor is connected to the second terminal of the sixth resistor.

[0018] The first capacitor is connected in parallel across the two ends of the sixth resistor.

[0019] Optionally, the second switching transistor is a P-type MOS transistor.

[0020] Optionally, the short - circuit detection module includes a first diode, a second diode, and a tenth resistor connected in series;

[0021] The first end of the tenth resistor is connected to the over - current detection end of the drive module, the second end of the tenth resistor is connected to the anode of the first diode, the cathode of the first diode is connected to the anode of the second diode, and the cathode of the second diode is connected to the first pole of the IGBT;

[0022] The short - circuit detection module further includes a second capacitor. The first end of the second capacitor is connected to the first end of the tenth resistor, and the second end of the second capacitor is grounded.

[0023] Optionally, the drive current amplification module includes a second triode and a third triode;

[0024] The base of the second triode is connected to the base of the third triode and then connected to the first end of an eleventh resistor. The second end of the eleventh resistor serves as the input end of the drive current amplification module;

[0025] The collector of the second triode is connected to the first set voltage, and the collector of the third triode is connected to the second set voltage;

[0026] The emitter of the second triode is connected to the first end of a twelfth resistor, the emitter of the third triode is connected to the first end of a thirteenth resistor. The second ends of the twelfth resistor and the thirteenth resistor are connected, and the connection end of the second ends of the twelfth resistor and the thirteenth resistor serves as the output end of the drive current discharge module;

[0027] The second triode is an NPN - type triode, and the third triode is a PNP - type triode.

[0028] In a second aspect, an embodiment of the present invention further provides a motor controller, including an inverter circuit. The inverter circuit includes a plurality of IGBT drive circuits, and each IGBT drive circuit includes the short - circuit protection circuit according to any embodiment of the present invention.

[0029] The short - circuit protection circuit provided by the embodiment of the present invention detects the first - pole current of the IGBT through a short - circuit detection module to determine whether the IGBT is short - circuited. When the short - circuit detection module detects that the IGBT is short - circuited, the soft - turn - off loop switching module controls the first switch tube to disconnect, so that the first resistor is connected to the turn - off loop, thereby completing the switching of the turn - off loop of the IGBT and realizing the decoupling of the short - circuit turn - off loop and the turn - off loop during normal driving. In this working condition, because the first resistor is connected to the turn - off loop, the resistance of the turn - off loop is increased, the turn - off speed of the IGBT is reduced, the soft - turn - off of the IGBT is realized, the occurrence of an excessive current change rate is avoided, and the over - voltage failure of the IGBT is avoided. This solves the problem in the prior art that due to the non - adjustable integrated parameters of the dedicated drive chip, it is impossible to be compatible with more types of IGBTs, resulting in the inability to realize the soft - turn - off of the IGBT. At the same time, the short - circuit turn - off parameters can be adjusted according to the type and parameters of the IGBT, so that the short - circuit protection design of the control system is no longer restricted by the internal parameters of the drive module IC, and the applicable range of the drive module is broadened. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of a short - circuit protection circuit provided by an embodiment of the present invention;

[0031] Figure 2 is a schematic structure of another short - circuit protection circuit provided by an embodiment of the present invention;

[0032] Figure 3 is a schematic structural diagram of another short - circuit protection circuit provided by an embodiment of the present invention;

[0033] Figure 4 is a schematic structural diagram of another short - circuit protection circuit provided by an embodiment of the present invention;

[0034] Figure 5 is a schematic structural diagram of another short - circuit protection circuit provided by an embodiment of the present invention;

[0035] Figure 6 is a schematic structural diagram of a motor controller provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0037] Figure 1Schematic diagram of a short - circuit protection circuit provided by an embodiment of the present invention. This short - circuit protection circuit can be applied to the drive circuit of a motor controller. The drive circuit of the motor controller is usually a two - level three - phase topology, including three bridge arms. Each bridge arm includes an IGBT at the upper and lower parts respectively. By controlling the switching of the 6 IGBTs, the corresponding phase circuit of the motor is conducted to control the motor. The short - circuit protection circuit provided by the embodiment of the present invention is connected to each IGBT and is used to protect the IGBT when the IGBT is overloaded or has a short - circuit over - current. Refer to Figure 1 , this short - circuit protection circuit includes: a short - circuit detection module 10, a soft - turn - off circuit switching module 20, and a drive current amplification module 30;

[0038] One end of the short - circuit detection module 10 is connected to the first pole of the IGBT, and the other end of the short - circuit detection module 10 is connected to the over - current detection terminal of the drive module IC. The short - circuit detection module 10 is used to detect the current of the first pole of the IGBT;

[0039] The soft - turn - off circuit switching module 20 includes a first switching transistor Q1. A first resistor R1 is connected in parallel between the first end and the second end of the first switching transistor Q1. The first end of the first switching transistor Q1 is connected to the output terminal of the drive module IC, and the second end of the first switching transistor Q1 is connected to the input terminal of the drive current amplification module 30; the control terminal of the first switching transistor Q1 is connected to the over - current detection terminal of the drive module IC through a switching circuit 21; the soft - turn - off circuit switching module 20 is used to switch the turn - off circuit of the IGBT through the first switching transistor Q1 according to the detection signal of the over - current detection terminal of the drive module IC;

[0040] The output terminal of the drive current amplification module 30 is connected to the gate of the IGBT. The drive current amplification module 30 is used to amplify the output signal of the soft - turn - off circuit switching module 20 and then drive the gate of the IGBT.

[0041] Specifically, high - voltage short - circuits on the drive side in the motor controller generally occur on the motor side. These short - circuit phenomena are ultimately reflected as a sharp increase in the drain current of the IGBT inside the motor controller. Therefore, in this embodiment, the first pole of the IGBT is exemplarily the drain of the IGBT. That is, this embodiment takes the detection of the drain current of the IGBT as an example to illustrate the working principle of the short - circuit protection circuit.

[0042] The short - circuit detection module 10 can control its own on - off state according to the change of the current at the drain of the IGBT. Specifically, in this embodiment, the short - circuit detection module 10 is connected between the drain of the IGBT and the IGBT drive module IC. When the IGBT is working normally, the short - circuit detection module 10 detects that the drain current of the IGBT is at a normal value. At this time, the short - circuit detection module 10 controls itself to be in the conducting state. When a short - circuit occurs, the drain current of the IGBT rises sharply, and the rise of the drain current causes the voltage Vds between the drain and the source of the IGBT to increase. At this time, the short - circuit detection module 10 controls itself to be in the open - circuit state, that is, the over - current detection terminal of the drive module IC is equivalent to an open circuit with the drain of the IGBT. The voltage of the over - current detection terminal of the drive module IC rises under the action of the internal pull - up voltage, thereby controlling the switch circuit 21 in the soft - turn - off loop switching module 20 to work, and further controlling the soft - turn - off loop switching module 20 to act correspondingly.

[0043] The soft - turn - off loop switching module 20 is used to switch the turn - off loop of the IGBT under the action of the switch circuit 21. The following further introduces the specific operating principle of the soft - turn - off loop switching module 20.

[0044] When the IGBT is working normally and the input terminal of the drive module IC is at a high level, the output terminal of the drive module IC outputs a high level. This high level is close to the first set voltage Vcc2, that is, the positive supply voltage of the secondary side of the drive module IC. At this time, the switch circuit 21 controls the first switch transistor Q1 to be in the off state, and the first resistor R1 is bypassed by the body diode of the first switch transistor Q1. The resistance value of the turn - off loop decreases, so that the IGBT can be quickly turned on through the drive current amplification module 30.

[0045] When the IGBT is working normally and the input terminal of the drive module IC is at a low level, the output terminal of the drive module IC outputs a low level. This low level is close to the second set voltage, that is, the negative supply voltage of the secondary side of the drive module IC. At this time, the switch circuit 21 controls the first switch transistor Q1 to be in the on state, and the first resistor R1 is bypassed by the first switch transistor Q1. Because the resistance value of the turn - off loop is small, the IGBT can be quickly turned off through the drive current amplification module 30.

[0046] As can be seen from the above, when the IGBT is in the normal working state, the switch circuit 21 does not act, so the soft - turn - off loop switching module 20 does not change the turn - off or conduction loop of the IGBT. Thus, the IGBT can be quickly turned off according to the normal turn - off loop or quickly turned on according to the normal conduction loop.

[0047] When the IGBT has a short circuit, at this time, since the short-circuit detection module 10 is in an open circuit state, it is equivalent to the overcurrent detection terminal of the drive module IC losing the pull-down resistor. Therefore, the output voltage of the overcurrent detection terminal starts to rise under the action of the internal pull-up voltage. When the voltage of the overcurrent detection terminal rises to the threshold voltage of the switching circuit 21, the switching circuit 21 outputs a low level, controlling the first switch tube Q1 to be in an off state. At this time, the first resistor R1 is connected in series with the turn-off loop, and the first resistor R1 increases the resistance value of the turn-off loop, thus reducing the turn-off speed of the IGBT, avoiding an excessive rate of change of current, and thus preventing the IGBT from overvoltage failure, achieving the effect of soft-turning off the IGBT. Thus, by adjusting the resistance value of the first resistor R1, the turn-off speed of the IGBT can be adjusted. Since the first resistor R1 is independent of the drive module IC, its resistance value can be flexibly selected as needed. Therefore, the soft-turn-off loop switching module 20 provided in this embodiment can decouple the turn-off loop during normal driving from the soft-turn-off loop, so that the operating parameters of the short-circuit protection circuit are no longer limited by the drive module IC. Therefore, the IGBT can be used in cooperation with drive module ICs with different drive parameters. At the same time, the first resistor R1 can be flexibly selected according to the type of the IGBT, the gate parameters of the IGBT, and the parasitic inductance of the main circuit to adjust the turn-off parameters of the IGBT, enabling the IGBT to be used in cooperation with more different types of drive module ICs, improving the applicability of the drive module IC.

[0048] The drive current amplification module 30 is connected to the gate of the IGBT and is used to amplify the output signal of the soft-turn-off loop switching module 20 and then act on the gate of the IGBT, thereby applying a corresponding drive signal to the gate of the IGBT to control the on and off of the IGBT.

[0049] In a specific embodiment, the drive module IC is a dedicated drive chip. At this time, the overcurrent detection terminal of the drive module IC is the desat pin of the drive chip, and the first set voltage Vcc2 is the positive supply voltage of the secondary side of the drive chip. In addition, the drive chip also outputs a negative supply voltage, which is the second set voltage in this embodiment.

[0050] The short-circuit protection circuit provided by the embodiment of the present invention detects the first-pole current of the IGBT through the short-circuit detection module to determine whether the IGBT is short-circuited. When the short-circuit detection module detects that the IGBT is short-circuited, the soft turn-off loop switching module controls the first switch tube to disconnect, so that the first resistor is connected to the turn-off loop, thereby completing the switching of the IGBT turn-off loop and realizing the decoupling of the short-circuit turn-off loop and the turn-off loop during normal driving. In this working condition, because the first resistor is connected to the turn-off loop, the resistance of the turn-off loop is increased, the turn-off speed of the IGBT is reduced, the soft turn-off of the IGBT is realized, the occurrence of too high a current change rate is avoided, and the overvoltage failure of the IGBT is avoided. It solves the problem in the prior art that the IGBT cannot realize soft turn-off because the integrated parameters of the dedicated drive chip are not adjustable and cannot be compatible with more types of IGBTs. At the same time, the short-circuit turn-off parameters can be adjusted according to the type and parameters of the IGBT, so that the short-circuit protection design of the control system is no longer restricted by the internal parameters of the drive module IC, and the applicable range of the drive module IC is broadened.

[0051] Optionally, Figure 2 is a schematic structural diagram of another short-circuit protection circuit provided by the embodiment of the present invention. On the basis of the above embodiment, referring to Figure 2 , the switching circuit 21 includes a second switch tube Q2, a voltage regulation module 211, and a third switch tube Q3;

[0052] The control end of the second switch tube Q2 is connected to the overcurrent detection end of the drive module IC. The first end of the second switch tube Q2 is connected to the control end of the voltage regulation module 211, and the second end of the second switch tube Q2 is grounded;

[0053] The input end of the voltage regulation module 211 is connected to the first set voltage Vcc2, and the output end of the voltage regulation module 211 is connected to the control end of the third switch tube Q3;

[0054] The control end of the third switch tube Q3 is also connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the first set voltage Vcc2; the first end of the third switch tube Q3 is connected to the first set voltage Vcc2, and the second end of the third switch tube Q3 is connected to the control end of the first switch tube Q1.

[0055] Specifically, the control terminal of the second switching transistor Q2 is connected to the overcurrent detection terminal of the driving module IC. When the IGBT is short-circuited, the output voltage of the overcurrent detection terminal is lifted under the action of the internal pull-up voltage. When the voltage of the overcurrent detection terminal rises to the threshold voltage of the second switching transistor Q2, the second switching transistor Q2 conducts. At this time, the voltage regulation module 211 outputs a high level, thereby controlling the voltage of the control terminal of the third switching transistor Q3 to be the same as the source voltage. Therefore, the third switching transistor Q3 is turned off, thereby controlling the first switching transistor Q1 to turn off. At this time, the first resistor R1 is connected in series to the turn-off circuit, completing the switching of the turn-off circuit of the IGBT.

[0056] When the IGBT is operating normally, the output voltage of the overcurrent detection terminal of the driving module IC is pulled down to the ground by the IGBT via the short-circuit detection module 10. Therefore, the output voltage of the overcurrent detection terminal of the driving module IC cannot reach the threshold voltage of the second switching transistor Q2, so the second switching transistor Q2 is turned off. Correspondingly, the voltage regulation module 211 outputs a low level, making a certain voltage difference maintained between the voltage of the control terminal and the source voltage of the third switching transistor Q3. At this time, the third switching transistor Q3 conducts, and then applies a certain driving voltage to the control terminal of the first switching transistor Q1. Combining with the voltage of the source of the first switching transistor Q1 (i.e., the output voltage of the driving module IC) to control the on / off state of the first switching transistor Q1. In this working condition, as analyzed above, the first resistor R1 is bypassed, and then the driving current amplification module 30 amplifies the output current of the driving module IC and drives the IGBT to conduct or disconnect quickly.

[0057] In one embodiment, the first switching transistor Q1, the second switching transistor Q2, and the third switching transistor Q3 are all MOS transistors. Among them, the first switching transistor Q1 and the second switching transistor Q2 are both N-type MOS transistors, and the third switching transistor Q3 is a P-type MOS transistor.

[0058] Optionally, Figure 3 is a schematic structural diagram of another short-circuit protection circuit provided by an embodiment of the present invention. On the basis of the above embodiment, referring to Figure 3 , the voltage regulation module 211 includes a first triode T1. The base of the first triode T1 is connected to the first end of a third resistor R3, and the second end of the third resistor R3 serves as the control terminal of the voltage regulation module 211. The emitter of the first triode T1 serves as the input terminal of the voltage regulation module 211. The first triode T1 is respectively connected to the first end of a fourth resistor R4 and the first end of a fifth resistor R5. The second end of the fourth resistor R4 is grounded, and the second end of the fifth resistor R5 serves as the output terminal of the voltage regulation module 211.

[0059] Specifically, when the first switching transistor Q1 is turned on, the base of the first triode T1 is powered, so that the first triode T1 starts to work. Since the first set voltage Vcc2 is applied to the control terminal of the third switching transistor Q3 after current limiting through the fifth resistor R5 via the first triode T1, and the control terminal of the third switching transistor Q3 is also connected to the first set voltage Vcc2 through the second resistor R2, by adjusting the resistance values of the fifth resistor R5 and the second resistor R2, there is no turn-on voltage difference between the gate and the source of the third switching transistor Q3 at this time, thereby controlling the third switching transistor Q3 to turn off. At this time, there is no driving voltage at the control terminal of the first switching transistor Q1, so the first switching transistor Q1 turns off, realizing the series connection of the first resistor R1 into the turn-off circuit.

[0060] In a specific embodiment, the third switching transistor Q3 is a P-type MOS transistor. When the gate voltage of the P-type MOS transistor is lower than the source voltage, the conduction condition of the P-type MOS transistor is satisfied. Based on this, in this embodiment, by adjusting the resistance values of the fifth resistor R5 and the second resistor R2, when the first triode T1 is turned on, the voltage applied to the control terminal of the third switching transistor Q3 is the same as the voltage applied to the source of the third switching transistor Q3, thereby controlling the third switching transistor Q3 to turn off. When the first triode T1 is turned off, the first set voltage Vcc2 is divided by the fifth resistor R5 and the fourth resistor R4, so that the voltage applied to the gate of the third switching transistor Q3 is lower than the voltage applied to the source of the third switching transistor Q3, so the third switching transistor Q3 is turned on at this time.

[0061] Optionally, Figure 4 is a schematic structural diagram of another short-circuit protection circuit provided by an embodiment of the present invention. On the basis of the above embodiment, referring to Figure 4 , the switching circuit 21 further includes a voltage dividing circuit 212. The input end of the voltage dividing circuit 212 is connected to the overcurrent detection end of the driving module IC, and the output end of the voltage dividing circuit 212 is connected to the control terminal of the second switching transistor Q2.

[0062] Specifically, the voltage dividing circuit 212 is used to divide the voltage signal at the overcurrent detection end of the driving module IC and then apply it to the control terminal of the second switching transistor Q2, so that when the divided voltage signal output by the voltage dividing circuit 212 reaches the turn-on threshold voltage of the second switching transistor Q2, the second switching transistor Q2 turns on.

[0063] In a specific embodiment, the voltage dividing circuit 212 is a resistor network voltage dividing circuit. Specifically, the voltage dividing circuit 212 includes an eighth resistor R8 and a ninth resistor R9. The first ends of the eighth resistor R8 and the ninth resistor R9 are respectively used as the input end and the output end of the voltage dividing circuit 212; the second end of the eighth resistor R8 is connected to the first end of the ninth resistor R9, and the second end of the ninth resistor R9 is grounded. When the divided voltage value on the ninth resistor R9 reaches the turn-on threshold voltage of the second switching transistor Q2, the second switching transistor Q2 turns on.

[0064] Optionally, based on the above embodiments, continue to refer to Figure 4 , the switching circuit 21 further includes a sixth resistor R6, a seventh resistor R7, and a first capacitor C1;

[0065] The first end of the sixth resistor R6 is connected to the first end of the third switching transistor Q3, and the second end of the sixth resistor R6 is connected to the control end of the first switching transistor Q1;

[0066] The first end of the seventh resistor R7 is connected to the first end of the first switching transistor Q1, and the second end of the seventh resistor R7 is connected to the second end of the sixth resistor R6;

[0067] The first capacitor C1 is connected in parallel across the two ends of the sixth resistor R6.

[0068] Specifically, when the third switching transistor Q3 is turned on, the first set voltage Vcc2 passes through the third switching transistor Q3 and is limited in current by the sixth resistor R6 and then applied to the control end of the first switching transistor Q1 as the driving voltage for the control end of the first switching transistor Q1. The sixth resistor R6 is specifically used to charge the gate capacitance during the conduction of the first switching transistor Q1. The first capacitor C1 connected in parallel across the two ends of the sixth resistor R6 can improve the charging speed of the first switching transistor Q1.

[0069] When the first switching transistor Q1 is turned off, the gate capacitance of the first switching transistor Q1 discharges through the seventh resistor R7 to ensure the stable operation of the first switching transistor Q1.

[0070] Optionally, Figure 5 is a schematic structural diagram of another short - circuit protection circuit provided by an embodiment of the present invention. Based on the above embodiments, refer to Figure 5 , the short - circuit detection module 10 includes a first diode D1, a second diode D2, and a tenth resistor R10 connected in series;

[0071] The first end of the tenth resistor R10 is connected to the over - current detection end of the driving module IC, the second end of the tenth resistor R10 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the first pole of the IGBT;

[0072] The short - circuit detection module 10 further includes a second capacitor C2. The first end of the second capacitor C2 is connected to the first end of the tenth resistor R10, and the second end of the second capacitor C2 is grounded.

[0073] Specifically, when the IGBT is operating normally, the first diode D1 and the second diode D2 are forward - conducting, and the output voltage of the over - current detection end of the driving module IC passes through the tenth resistor R10, the first diode D1, and the second diode D2 and is grounded through the IGBT, and the voltage of the over - current detection end is pulled down.

[0074] When the IGBT is short-circuited, the drain-source voltage of the IGBT surges. At this time, the gate voltage of the IGBT rises, so that the cathode voltages of the first diode D1 and the second diode D2 are higher than the anode voltages, causing the first diode D1 and the second diode D2 to turn off. As a result, the voltage at the overcurrent detection terminal of the drive module IC is lifted, enabling the output voltage of the overcurrent detection terminal to charge the first capacitor C1. When the voltage of the first capacitor C1 rises to a certain value, the voltage-dividing signal output via the second voltage-dividing circuit reaches the threshold voltage of the second switching transistor Q2, thereby controlling the second switching transistor Q2 to conduct, and the soft turn-off circuit switching module 20 starts to function to control the first switching transistor Q1 to conduct.

[0075] It can be seen that by setting the short-circuit detection module 10, it is possible to detect whether the IGBT is short-circuited. When the IGBT short-circuit is detected, by feeding back an output signal to the overcurrent detection terminal of the drive module IC, the soft turn-off circuit switching module 20 is further controlled to start working.

[0076] Optionally, continuing to refer to Figure 5 , on the basis of the above embodiment, the drive current amplification module 30 includes a second triode T2 and a third triode T3;

[0077] The base of the second triode T2 is connected to the base of the third triode T3 and then connected to the first end of the eleventh resistor. The second end of the eleventh resistor R11 serves as the input terminal of the drive current amplification module 30;

[0078] The collector of the second triode T2 is connected to the first set voltage Vcc2, and the collector of the third triode T3 is connected to the second set voltage Vee2;

[0079] The emitter of the second triode T2 is connected to the first end of the twelfth resistor R12, and the emitter of the third triode T3 is connected to the first end of the thirteenth resistor R13. The second ends of the twelfth resistor R12 and the thirteenth resistor R13 are connected, and the connection end of the second end of the twelfth resistor R12 and the second end of the thirteenth resistor R13 serves as the output terminal of the drive current discharge module;

[0080] The second triode T2 is an NPN-type triode, and the third triode T3 is a PNP-type triode.

[0081] Specifically, the drive current amplification module 30 is a push-pull circuit composed of two triodes with the same parameters to amplify the output signal at the output terminal of the drive module IC and then drive the gate of the IGBT.

[0082] When the voltage of the eleventh resistor R11 is at a low level, the second triode T2 is turned off and the third triode T3 is turned on. At this time, the current signal at the output end of the drive module IC is amplified by the third triode T3 to drive the IGBT, so as to control the on-off of the IGBT.

[0083] When the voltage of the eleventh resistor R11 is at a high level, the second triode T2 is turned on and the third triode T3 is turned off. At this time, the drive current amplification module 30 amplifies the output current of the drive module IC through the second triode T2 to drive the IGBT, so as to control the on-off of the IGBT.

[0084] An embodiment of the present invention further provides a motor controller. Figure 6 FIG. is a schematic structural diagram of the motor controller provided by the embodiment of the present invention. The motor controller 100 includes an inverter circuit 110. The inverter circuit 110 includes a plurality of IGBT drive circuits 120. Each IGBT drive circuit 120 includes the short-circuit protection circuit provided by any embodiment of the present invention. Therefore, the embodiment of the present invention has the beneficial effects described in any of the above embodiments.

[0085] Note that the above is only a preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A short-circuit protection circuit is applied to an IGBT drive circuit. The IGBT drive circuit includes an IGBT and a drive module, and is characterized in that, The short - circuit protection circuit includes: a short - circuit detection module, a soft - turn - off loop switching module, and a drive current amplification module; The input end of the short - circuit detection module is connected to the first pole of the IGBT, and the output end of the short - circuit detection module is connected to the over - current detection end of the drive module. The short - circuit detection module is used to detect the current of the first pole of the IGBT; The soft - turn - off loop switching module includes a first switching transistor. A first resistor is connected in parallel between the first end and the second end of the first switching transistor. The first end of the first switching transistor is connected to the output end of the drive module, and the second end of the first switching transistor is connected to the input end of the drive current amplification module. The control end of the first switching transistor is connected to the over - current detection end of the drive module through a switching circuit. The soft - turn - off loop switching module is used to switch the turn - off loop of the IGBT through the first switching transistor according to the detection signal of the over - current detection end of the drive module; The output end of the drive current amplification module is connected to the gate of the IGBT. The drive current amplification module is used to amplify the output signal of the drive module and then drive the gate of the IGBT; The first switching transistor is an N - type MOS transistor.

2. The short-circuit protection circuit according to claim 1, wherein The switching circuit includes a second switching transistor, a voltage regulation module, and a third switching transistor; The control end of the second switching transistor is connected to the over - current detection end of the drive module. The first end of the second switching transistor is connected to the control end of the voltage regulation module, and the second end of the second switching transistor is grounded; The input end of the voltage regulation module is connected to a first set voltage, and the output end of the voltage regulation module is connected to the control end of the third switching transistor; The control end of the third switching transistor is also connected to the first end of a second resistor. The second end of the second resistor is connected to the first set voltage. The first end of the third switching transistor is connected to the first set voltage, and the second end of the third switching transistor is connected to the control end of the first switching transistor.

3. The short - circuit protection circuit according to claim 2, wherein, The voltage regulation module includes a first triode. The base of the first triode is connected to the first end of a third resistor, and the second end of the third resistor serves as the control end of the voltage regulation module. The emitter of the first triode serves as the input end of the voltage regulation module. The collector of the first triode is respectively connected to the first end of a fourth resistor and the first end of a fifth resistor. The second end of the fourth resistor is grounded, and the second end of the fifth resistor serves as the output end of the voltage regulation module.

4. The short-circuit protection circuit according to claim 2, wherein The switching circuit further includes a voltage - dividing circuit. The input end of the voltage - dividing circuit is connected to the over - current detection end of the drive module, and the output end of the voltage - dividing circuit is connected to the control end of the second switching transistor.

5. The short - circuit protection circuit according to claim 4, wherein, The voltage - dividing circuit includes an eighth resistor and a ninth resistor. The first end of the eighth resistor and the first end of the ninth resistor respectively serve as the input end and the output end of the voltage - dividing circuit. The second end of the eighth resistor is connected to the first end of the ninth resistor, and the second end of the ninth resistor is grounded.

6. The short-circuit protection circuit according to claim 2, wherein The switching circuit further includes a sixth resistor, a seventh resistor, and a first capacitor; The first end of the sixth resistor is connected to the first end of the third switching transistor, and the second end of the sixth resistor is connected to the control end of the first switching transistor; The first end of the seventh resistor is connected to the first end of the first switching transistor, and the second end of the seventh resistor is connected to the second end of the sixth resistor; The first capacitor is connected in parallel across the two ends of the sixth resistor.

7. The short-circuit protection circuit according to claim 2, wherein, The second switching transistor is a P-type MOS transistor.

8. The short-circuit protection circuit according to claim 1, wherein, The short-circuit detection module includes a first diode, a second diode, and a tenth resistor connected in series; The first end of the tenth resistor is connected to the overcurrent detection end of the driving module, the second end of the tenth resistor is connected to the anode of the first diode, the cathode of the first diode is connected to the anode of the second diode, and the cathode of the second diode is connected to the first pole of the IGBT; The short-circuit detection module further includes a second capacitor, the first end of the second capacitor is connected to the first end of the tenth resistor, and the second end of the second capacitor is grounded.

9. The short-circuit protection circuit according to claim 2, characterized in that The drive current amplification module includes a second triode and a third triode; The base of the second triode and the base of the third triode are connected and then connected to the first end of an eleventh resistor, and the second end of the eleventh resistor serves as the input end of the drive current amplification module; The collector of the second triode is connected to the first set voltage, and the collector of the third triode is connected to the second set voltage; The emitter of the second triode is connected to the first end of a twelfth resistor, the emitter of the third triode is connected to the first end of a thirteenth resistor, the second ends of the twelfth resistor and the thirteenth resistor are connected, and the connection end of the second ends of the twelfth resistor and the thirteenth resistor serves as the output end of the drive current amplification module; The second triode is an NPN-type triode, and the third triode is a PNP-type triode.

10. A motor controller, characterized in that, It includes an inverter circuit, the inverter circuit includes a plurality of IGBT drive circuits, and each of the IGBT drive circuits includes a short-circuit protection circuit according to any one of claims 1-9.

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