A gate drive circuit and control method thereof

Abstract

A gate drive circuit and control method thereof, comprising a main three-terminal transistor and a junction temperature control circuit, wherein the junction temperature control circuit is used to obtain the junction temperature difference between the measured junction temperature and the preset reference junction temperature based on the measured junction temperature on the main three-terminal transistor when the main three-terminal transistor is turned on; when the junction temperature difference is less than the preset first threshold junction temperature, the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor is reduced, and when the junction temperature difference is greater than the preset second threshold junction temperature, the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor is increased. In the present disclosure, the junction temperature control circuit can adjust the turn-on and turn-off losses of the three-terminal transistor, smooth the junction temperature fluctuation, and thereby realize the real-time adjustment of the turn-on and turn-off losses of the main three-terminal transistor and realize the junction temperature control.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of power electronics, and in particular relates to a gate drive circuit and a control method thereof. Background Art

[0002] In high-power applications, the system device current is large, the corresponding loss is high, and the device junction temperature rises significantly. Power devices made of traditional silicon (Si) materials have low temperature resistance, narrow bandgap, and low blocking voltage, which are difficult to meet the requirements of the new generation of power systems. During the operation of the device, switching loss will increase the junction temperature, change the electrical characteristics of the three-terminal transistor, and change the switching characteristics, which will lead to a decrease in life. Therefore, active gate drive circuits with switching loss regulation capabilities have great research significance. Summary of the invention

[0003] In order to solve the above technical problems, a first objective of the present disclosure is to provide a gate drive circuit with switching loss regulation capability.

[0004] A second objective of the present disclosure is to provide a control method based on the above-mentioned gate drive circuit.

[0005] In order to achieve the first objective of the present disclosure, the technical solution adopted by the present disclosure is as follows:

[0006] A gate drive circuit, comprising:

[0007] A main three-terminal transistor, based on receiving an on signal or an off signal, turns on or off the main three-terminal transistor;

[0008] a junction temperature control circuit connected to the control electrode of the main three-terminal transistor, for obtaining a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature on the main three-terminal transistor when the main three-terminal transistor is turned on; when the junction temperature difference is less than a preset first threshold junction temperature, reducing the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; and when the junction temperature difference is greater than a preset second threshold junction temperature, increasing the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor;

[0009] The second threshold junction temperature is greater than or equal to the first threshold junction temperature.

[0010] Optionally, the junction temperature control circuit includes:

[0011] A signal feedback circuit is connected to the main three-terminal transistor, obtains a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature on the main three-terminal transistor, compares the junction temperature difference with a first threshold junction temperature or a second threshold junction temperature, and sends a control signal to the execution circuit according to the comparison result;

[0012] An execution circuit is connected to the control electrode and the signal feedback circuit of the main three-terminal transistor respectively, and the execution circuit is used to reduce the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor or increase the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor according to the control signal.

[0013] Optionally, the execution circuit includes an on-control circuit and an off-control circuit.

[0014] The signal feedback circuit is connected to the control electrode of the main three-terminal transistor through the turn-on control circuit;

[0015] The signal feedback circuit is connected to the control electrode of the main three-terminal transistor through the shutdown control circuit.

[0016] Optionally, the turn-on control circuit includes a turn-on voltage regulating module, a first three-terminal transistor, a first diode and a first capacitor.

[0017] The input end of the turn-on voltage regulating module is connected to the signal feedback circuit; the first output end of the turn-on voltage regulating module is connected to the control electrode of the first three-terminal transistor, and the second output end of the turn-on voltage regulating module is connected to the first electrode of the first three-terminal transistor;

[0018] The first electrode of the first three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a first diode; the second electrode of the first three-terminal transistor is an input end of an on signal;

[0019] The control electrode of the first three-terminal transistor is connected to the first electrode of the first three-terminal transistor through the first capacitor.

[0020] Optionally, the shutdown control circuit includes a shutdown voltage regulating module, a second three-terminal transistor, a second diode and a second capacitor.

[0021] The input end of the shutdown voltage regulation module is connected to the signal feedback circuit; the first output end of the shutdown voltage regulation module is connected to the control electrode of the second three-terminal transistor, and the second output end of the shutdown voltage regulation module is connected to the first electrode of the second three-terminal transistor;

[0022] The second electrode of the second three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a second diode; the first electrode of the second three-terminal transistor is an input end of a shutdown signal;

[0023] The control electrode of the second three-terminal transistor is connected to the first electrode of the second three-terminal transistor through the second capacitor.

[0024] Optionally, the signal feedback circuit includes:

[0025] a sensor connected to the main three-terminal transistor and configured to detect a measured junction temperature on the main three-terminal transistor;

[0026] A controller is connected to the sensor, the turn-on control circuit and the turn-off control circuit respectively. The controller is used to obtain a junction temperature difference between a measured junction temperature and a preset reference junction temperature based on a measured junction temperature on the main three-terminal transistor, compare the junction temperature difference with a first threshold junction temperature or a second threshold junction temperature, and send a control signal to the execution circuit according to the comparison result.

[0027] Optionally, the controller is connected to the voltage regulation module via a digital isolator.

[0028] Optionally, the gate drive circuit further comprises an on / off circuit connected to the control electrode of the main three-terminal transistor, and the on / off circuit can send an on signal or an off signal to the control electrode of the main three-terminal transistor.

[0029] In order to achieve the second purpose of the present disclosure, the technical solution adopted by the present disclosure is as follows:

[0030] A junction temperature control method based on the above gate drive circuit,

[0031] The main three-terminal transistor is turned on or off under the control of an on signal or an off signal;

[0032] The junction temperature control circuit acquires the measured junction temperature on the main three-terminal transistor, and obtains a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature;

[0033] When the junction temperature difference is less than a preset first threshold junction temperature, the junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; when the junction temperature difference is greater than a preset second threshold junction temperature, the junction temperature control circuit increases the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; wherein the second threshold junction temperature is greater than or equal to the first threshold junction temperature.

[0034] Optionally, the junction temperature control circuit includes a signal feedback circuit and an on-control circuit connected to the signal feedback circuit, and the on-control circuit includes an on-voltage regulating module, a first three-terminal transistor, a first diode and a first capacitor;

[0035] The input end of the turn-on voltage regulating module is connected to the signal feedback circuit; the first output end of the turn-on voltage regulating module is connected to the control electrode of the first three-terminal transistor, and the second output end of the turn-on voltage regulating module is connected to the first electrode of the first three-terminal transistor; the first electrode of the first three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a first diode; the second electrode of the first three-terminal transistor is the input end of the turn-on signal; the control electrode of the first three-terminal transistor is connected to the first electrode of the first three-terminal transistor through the first capacitor;

[0036] The junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor, including:

[0037] The turn-on voltage regulating module reduces the voltage between the control electrode and the first electrode of the first three-terminal transistor;

[0038] The junction temperature control circuit increases the current of the on signal or the off signal input to the control electrode of the main three-terminal transistor, including:

[0039] The turn-on voltage regulating module increases the voltage between the control electrode and the first electrode of the first three-terminal transistor.

[0040] Optionally, the junction temperature control circuit includes a signal feedback circuit and a shutdown control circuit connected to the signal feedback circuit, the shutdown control circuit includes a shutdown voltage adjustment module, a second three-terminal transistor, a second diode and a second capacitor,

[0041] The input end of the shutdown voltage regulating module is connected to the signal feedback circuit; the first output end of the shutdown voltage regulating module is connected to the control electrode of the second three-terminal transistor, and the second output end of the shutdown voltage regulating module is connected to the first electrode of the second three-terminal transistor; the second electrode of the second three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a second diode; the first electrode of the second three-terminal transistor is the input end of the shutdown signal; the control electrode of the second three-terminal transistor is connected to the first electrode of the second three-terminal transistor through the second capacitor;

[0042] The junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor, including:

[0043] The off voltage regulating module reduces the voltage between the control electrode and the first electrode of the second three-terminal transistor;

[0044] The junction temperature control circuit increases the current of the on signal or the off signal input to the control electrode of the main three-terminal transistor, including:

[0045] The turn-off voltage regulating module increases the voltage between the control electrode and the first electrode of the second three-terminal transistor.

[0046] The present invention adds a junction temperature control circuit on the basis of a traditional three-terminal transistor driving circuit. When the junction temperature difference is less than a preset first threshold junction temperature, the junction temperature of the main three-terminal transistor is low and the conduction loss is small. The junction temperature control circuit reduces the current of the control electrode of the main three-terminal transistor, increases the turn-on loss, and raises the junction temperature of the main three-terminal transistor. When the junction temperature difference is greater than a preset second threshold junction temperature, the junction temperature of the main three-terminal transistor is high and the conduction loss is large. The current of the control electrode of the main three-terminal transistor is increased, the turn-on loss is reduced, and the junction temperature of the main three-terminal transistor is lowered.

[0047] The junction temperature control circuit can adjust the turn-on and turn-off losses of the three-terminal transistor, smooth the junction temperature fluctuation, and then realize the real-time adjustment of the turn-on and turn-off losses of the main three-terminal transistor to realize junction temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0049] Figure 1 Schematic diagram of the gate drive circuit in the present disclosure.

[0050] Figure 2 This is the turn-on waveform of the three-terminal transistor.

[0051] Figure 3 This is the turn-off waveform of the three-terminal transistor.

[0052] Figure 4 The experimental data of the turn-on loss in the gate drive circuit of the present invention.

[0053] Figure 5 The experimental data of the turn-off loss in the gate drive circuit disclosed in the present invention.

[0054] Figure 6 Schematic diagram of the control principle of the gate drive circuit disclosed in the present invention.

[0055] Figure 7 The figure is a comparison diagram of the junction temperature of the gate drive circuit disclosed in the present invention and the gate drive circuit in the prior art. DETAILED DESCRIPTION

[0056] The present disclosure is further described in detail below in conjunction with the accompanying drawings and implementations. It is understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present disclosure. It should also be noted that, for ease of description, only the parts related to the present disclosure are shown in the accompanying drawings.

[0057] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0058] The three-terminal transistor includes a bipolar transistor (such as an IGBT) or a field effect transistor (such as a MOSFET), etc.; the three-terminal transistor includes a control electrode, a first electrode, and a second electrode, wherein the control electrode is a gate or a base, one of the first electrode and the second electrode is a source or a collector, and the other is a drain or an emitter.

[0059] See also Figure 1 , Figure 6 As shown, some embodiments of the present disclosure provide a gate drive circuit, including a main three-terminal transistor 1 and a junction temperature control circuit 3; the junction temperature control circuit 3 is connected to the control electrode of the main three-terminal transistor 1; wherein,

[0060] A main three-terminal transistor 1 is used to turn on or off the main three-terminal transistor 1 based on a received turn-on signal or turn-off signal; the main three-terminal transistor 1 can be a triode, an IGBT, a MOSFET, a BJT, etc., the IGBT device can be a U-IGBT, an NPT-IGBT, an SDB-IGBT, etc., the MOSFET device can be an N-type MOSFET device, a P-type MOSFET device, a SiCMOSFET or a Si MOSFET, etc.; the model can be SCT30N120, SCT3030ALHR, SCT3017AL, SCT2120AF, SCT3017ALHR, SCT3022AL, etc.

[0061] The junction temperature control circuit 3 is used for controlling the junction temperature T of the main three-terminal transistor 1 when the main three-terminal transistor 1 is turned on. j , obtain the measured junction temperature T j With the preset reference junction temperature T jref The junction temperature difference ΔT j ;

[0062] When the junction temperature difference ΔT j is lower than the preset first threshold junction temperature T jth1When the junction temperature T of the main three-terminal transistor 1 is low, the conduction loss is small, and the junction temperature control circuit 3 reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor 1, so that the turn-on loss increases, thereby increasing the junction temperature T of the main three-terminal transistor 1; the current of the turn-on signal or the turn-off signal can be reduced to a certain value, or can be reduced proportionally to the minimum allowable current.

[0063] When the junction temperature difference ΔT j Greater than the preset second threshold junction temperature T jth2 When the load junction temperature T is high, the conduction loss is large, and the junction temperature control circuit 3 increases the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor 1 to reduce the turn-on loss, thereby reducing the junction temperature T of the main three-terminal transistor 1. The current of the turn-on signal or the turn-off signal can be increased to a certain value, or can be increased proportionally to the maximum allowable current.

[0064] When the junction temperature difference ΔT j At the first threshold junction temperature T jth1 and the second threshold junction temperature T jth2 When the junction temperature difference ΔT is between ΔT and ΔT, the control current of the main three-terminal transistor 1 can be set to be unchanged or to be changed according to the junction temperature difference ΔT. j At the first threshold junction temperature T jth1 and the second threshold junction temperature T jth2 The control electrode current of the main three-terminal transistor 1 is adjusted by the ratio between them, and the corresponding current can be calculated by interpolation method.

[0065] In this embodiment, the reference junction temperature T jref The value can be set to: jref =P loss ×R thja +T a , where P loss is the rated turn-on and turn-off loss of the main three-terminal transistor 1, R thja is the thermal resistance from case to ambient of the main three-terminal transistor 1, T a is the ambient temperature.

[0066] In this embodiment, the second threshold junction temperature T jth2 Greater than or equal to the first threshold junction temperature T jth1 The first threshold junction temperature T jth1 The value can be set to 0.1-0.3 times the reference junction temperature T jref The value is negative, and the second threshold junction temperature T jth2 The value can be set to 0.1-0.3 times the reference junction temperature T jref The first threshold junction temperature T jth1 and the second threshold junction temperature T jth2 They can also all be 0.

[0067] The on-signal or off-signal may be provided by an on-off circuit 2, and the on-signal or off-signal output by the on-off circuit 2 may be a digital signal or an analog signal, and may include an on-signal and an off-signal; the on-signal is a signal for turning on the main three-terminal transistor 1, and the off-signal is a signal for turning off the main three-terminal transistor 1. The on-off circuit 2 is, for example, an analog gate drive circuit, a PWM gate drive circuit, and the like.

[0068] In some specific embodiments, the junction temperature control circuit 3 includes a signal feedback circuit 31 and an execution circuit 32 ; the execution circuit 32 is connected to the signal feedback circuit 31 , and the execution circuit 32 is also connected to the control electrode of the main three-terminal transistor 1 .

[0069] The signal feedback circuit 31 can be based on the measured junction temperature T of the main three-terminal transistor 1 j , get the measured junction temperature T j With the preset T jref The junction temperature difference ΔT j , the junction temperature difference ΔT j The first threshold junction temperature T jth1 Or the second threshold junction temperature T jth2 Compare, and send a control signal to the execution circuit 32 according to the comparison result; the control signal may include a control signal for reducing the current and a control signal for increasing the current; the control signal may be in the form of an analog control signal or a digital control signal light.

[0070] The execution circuit 32 is used to reduce the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor 1 or increase the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor 1 according to the control signal; when the execution circuit 32 receives a control signal for reducing the current sent by the controller 312, the execution circuit 32 controls the current of the control electrode of the main three-terminal transistor 1 to decrease; when the execution circuit 32 receives a control signal for increasing the current sent by the controller 312, the execution circuit 32 controls the current of the control electrode of the main three-terminal transistor 1 to increase.

[0071] In some embodiments, the execution circuit 32 includes an on-control circuit 321 and an off-control circuit 322, wherein the on-control circuit 321 is used to adjust the current of the on-signal of the on-process, and the off-control circuit 322 is used to adjust the current of the off-signal of the off-process. The signal feedback circuit 31 is connected to the control electrode of the main three-terminal transistor 1 through the on-control circuit 321; the signal feedback circuit 31 is connected to the control electrode of the main three-terminal transistor 1 through the off-control circuit 322. Of course, the execution circuit 32 can also be composed of an integral circuit to adjust the current of the on-off signal of the on-process and the off-process.

[0072] In a specific embodiment, the on control circuit 321 includes an on voltage regulating module, a first three-terminal transistor M on , the first diode D 1 and the first capacitor C on The voltage regulation module can be turned on using a linear regulator LDO for linearly adjusting the first three-terminal transistor M on The voltage between the control electrode and the first electrode of the main three-terminal transistor 1 can be adjusted linearly, so that the current of the turn-on signal entering the control electrode of the main three-terminal transistor 1 can be adjusted linearly. The turn-on voltage adjustment module can also adopt other methods that can adjust the voltage of the first three-terminal transistor M on A module for controlling the voltage between the control electrode and the first electrode;

[0073] The input end of the linear regulator LDO is connected to the signal feedback circuit 31; the first output end of the linear regulator LDO is connected to the first three-terminal transistor M on The second output terminal of the linear regulator LDO is connected to the control electrode of the first three-terminal transistor M on The first electrode of the first three-terminal transistor M on The first electrode also passes through the first diode D 1 Then connected to the control electrode of the main three-terminal transistor 1, the first diode D 1 A current signal for conducting and turning on only the main three-terminal transistor 1;

[0074] The first three-terminal transistor M on The second electrode of is the input end of the on / off signal, and is connected to the on / off circuit 2. on The control electrode is connected to the first capacitor C on and the first three-terminal transistor M on The first pole connection.

[0075] After the linear regulator LDO in the on-state control circuit 321 receives the on-state control signal output by the signal feedback circuit 31, the linear regulator LDO obtains the adjustment of the first three-terminal transistor M according to the on-state control signal. on The linear regulator LDO adjusts the voltage of the first three-terminal transistor M on The voltage between the control electrode and the first electrode of the first three-terminal transistor M on The conduction degree of the main three-terminal transistor 1 is adjusted to adjust the current of the turn-on signal entering the control electrode of the main three-terminal transistor 1, thereby adjusting the junction temperature.

[0076] In another specific embodiment, similar to the structure of the on control circuit 321, the off control circuit 322 includes a off voltage regulating module, a second three-terminal transistor M off, the second diode D 2 and the second capacitor C 2 The shutdown voltage regulation module can also use a linear regulator LDO, or other regulators that can regulate the first three-terminal transistor M on module of the voltage between the control electrode and the first electrode.

[0077] The input end of the linear regulator LDO is connected to the signal feedback circuit 31; the first output end of the linear regulator LDO is connected to the second three-terminal transistor M off The control electrode of the linear regulator LDO is connected to the second output terminal of the second three-terminal transistor M off The first electrode of the second three-terminal transistor M off The second electrode also passes through the second diode D 2 Then connected to the control electrode of the main three-terminal transistor 1, the second diode D 2 A current signal for turning on and off only the main three-terminal transistor 1;

[0078] The second three-terminal transistor M off The first terminal of the transistor M is the input terminal of the shutdown signal and is connected to the on-off circuit 2; the second three-terminal transistor M off The control electrode is connected to the second capacitor C 2 and the second three-terminal transistor M off The first pole connection.

[0079] After the linear regulator LDO in the shutdown control circuit 322 receives the shutdown control signal output by the signal feedback circuit 31, it obtains the adjustment of the first three-terminal transistor M according to the shutdown control signal. on The linear regulator LDO adjusts the voltage of the second three-terminal transistor M off The voltage between the control electrode and the first electrode is adjusted to adjust the second three-terminal transistor M off The conduction degree of the main three-terminal transistor 1 is adjusted to thereby adjust the current of the shutdown signal entering the control electrode of the main three-terminal transistor 1, thereby adjusting the junction temperature.

[0080] In some embodiments, the signal feedback circuit 31 includes a sensor 311 and a controller 312, wherein the sensor 311 is connected to the main three-terminal transistor 1, and the controller 312 is connected to the sensor 311, the on control circuit 321 and the off control circuit 322 respectively.

[0081] The sensor 311 is used to detect the measured junction temperature T j ; The sensor 311 can be a temperature sensor mounted on the main three-terminal transistor 1, or it can be a temperature sensing transistor integrated on the main three-terminal transistor 1.

[0082] The controller 312 is used to determine the measured junction temperature T of the main three-terminal transistor 1 based on the measured junction temperature T j , get the measured junction temperature T j With reference junction temperature T jref The junction temperature difference ΔT j , the junction temperature difference ΔT j The first threshold junction temperature T jth1 Or the second threshold junction temperature T jth2 Compare, and send a control signal to the execution circuit 32 according to the comparison result. The controller 312 can be a PLC, a single chip microcomputer, etc.

[0083] When the measured junction temperature T j With the preset reference junction temperature T jref The junction temperature difference ΔT j Less than the first threshold junction temperature T jth1 When the controller 312 sends a control signal to the execution circuit 32 to control the current of the control electrode of the main three-terminal transistor 1 to decrease, that is, to control the first three-terminal transistor M on and / or a second three-terminal transistor M off The voltage between the control electrode and the first electrode increases;

[0084] When the junction temperature T j With the preset reference junction temperature T jref The junction temperature difference ΔT j Greater than the second threshold junction temperature T jth2 When comparing, the controller 312 sends a control signal to the execution circuit 32 to increase the current of the control electrode of the main three-terminal transistor 1, that is, to control the first three-terminal transistor M on and / or a second three-terminal transistor M off The voltage between the control electrode and the first electrode decreases.

[0085] In one embodiment, the controller 312 is connected to the voltage regulator via a digital isolator 313; the digital isolator is used to isolate the high-voltage power side from the low-voltage power side to prevent the high-voltage side switch oscillation from affecting the low-voltage side control board.

[0086] Combination Figure 1 , Figure 6 As shown, some embodiments of the present disclosure also provide a junction temperature control method based on the above-mentioned gate drive circuit, the method comprising:

[0087] The main three-terminal transistor 1 is turned on or off under the control of an on signal or an off signal;

[0088] The junction temperature control circuit 3 obtains the measured junction temperature T of the main three-terminal transistor 1 j , and based on the measured junction temperature T jGet the measured junction temperature T j With the preset T jref The junction temperature difference ΔT j ;

[0089] When the junction temperature difference ΔT j is lower than the preset first threshold junction temperature T jth1 When the junction temperature difference ΔT j Greater than the preset second threshold junction temperature T jth2 When the junction temperature control circuit 3 increases the current of the on signal or off signal input to the control electrode of the main three-terminal transistor 1; wherein the second threshold junction temperature T jth2 Greater than or equal to the first threshold junction temperature T jth1 .

[0090] The junction temperature control method generally includes turn-on junction temperature control and turn-off junction temperature control;

[0091] In some embodiments, a junction temperature control method is provided, wherein the junction temperature control circuit 3 may include a signal feedback circuit 31, an on control circuit 321 connected to the signal feedback circuit 31, and the on control circuit 321 includes an on voltage regulating module, a first three-terminal transistor M on , the first diode D 1 and the first capacitor C on ;

[0092] The input end of the opening voltage regulation module is connected to the signal feedback circuit 31; the first output end of the opening voltage regulation module is connected to the first three-terminal transistor M on The control electrode of the first three-terminal transistor M is connected to the second output terminal of the voltage regulating module, and the second output terminal of the voltage regulating module is connected to the first three-terminal transistor M on The first electrode of the first three-terminal transistor M on The first electrode also passes through the first diode D 1 Then connected to the control electrode of the main three-terminal transistor 1, the first diode D 1 A current signal for conducting and turning on only the main three-terminal transistor 1;

[0093] The first three-terminal transistor M on The second electrode of is the input end of the on / off signal, and is connected to the on / off circuit 2. on The control electrode is connected to the first capacitor C on and the first three-terminal transistor M on The first pole connection.

[0094] In the above-mentioned conduction junction temperature control method of the conduction junction temperature control circuit 3:

[0095] The junction temperature control circuit 3 reduces the current of the on signal or off signal input to the control electrode of the main three-terminal transistor 1, including:

[0096] The turn-on voltage regulating module reduces the first three-terminal transistor M on The voltage between the control electrode and the first electrode;

[0097] The junction temperature control circuit 3 increases the current of the on signal or off signal input to the control electrode of the main three-terminal transistor 1, including:

[0098] The turn-on voltage regulating module increases the voltage of the first three-terminal transistor M on The voltage between the control electrode and the first electrode.

[0099] Furthermore, the on-junction temperature control method is specifically:

[0100] When the junction temperature difference ΔT j Less than the first threshold junction temperature T jth1 When the turn-on voltage regulating module turns the first three-terminal transistor M on The voltage V between the control electrode and the first electrode gson , adjusted to the first three-terminal transistor M on The minimum allowable turn-on voltage V between the control electrode and the first electrode gson,min ;

[0101] When the junction temperature difference ΔT j Greater than the second threshold junction temperature T jth2 When the turn-on voltage regulating module turns the first three-terminal transistor M on The voltage between the control electrode and the first electrode is adjusted to the first three-terminal transistor M on The maximum allowable turn-on voltage V between the control electrode and the first electrode gson,max ;

[0102] When the junction temperature difference ΔT j Greater than the first threshold junction temperature T jth1 , and is less than the second threshold junction temperature T jth2 When the turn-on voltage regulating module turns the first three-terminal transistor M on The voltage between the control electrode and the first electrode is proportionally adjusted to the maximum allowable turn-on voltage V gson,max The minimum allowable voltage V gson,min The corresponding voltage between

[0103] In some other embodiments, a shutdown junction temperature control method is provided, wherein the junction temperature control circuit 3 specifically includes a signal feedback circuit 31, a shutdown control circuit 322 connected to the signal feedback circuit 31, and the shutdown control circuit 322 includes a shutdown voltage adjustment module, a second three-terminal transistor M off , the second diode D 2 and the second capacitor C 2 .

[0104] The input end of the shutdown voltage regulation module is connected to the signal feedback circuit 31; the first output end of the shutdown voltage regulation module is connected to the second three-terminal transistor M off The control electrode of the transistor M is connected to the second output terminal of the voltage regulating module and the second three-terminal transistor M is turned off. off The first electrode of the second three-terminal transistor M off The second electrode also passes through the second diode D 2 Then connected to the control electrode of the main three-terminal transistor 1, the second diode D 2 A current signal for turning on and off only the main three-terminal transistor 1;

[0105] The second three-terminal transistor M off The first terminal of the transistor M is the input terminal of the shutdown signal and is connected to the on-off circuit 2; the second three-terminal transistor M off The control electrode is connected to the second capacitor C 2 and the second three-terminal transistor M off The first pole connection.

[0106] In the shutdown junction temperature control method of the above-mentioned shutdown junction temperature control circuit 3:

[0107] The junction temperature control circuit 3 reduces the current of the on signal or off signal input to the control electrode of the main three-terminal transistor 1, including:

[0108] The turn-on voltage regulating module reduces the second three-terminal transistor M off The voltage between the control electrode and the first electrode;

[0109] The junction temperature control circuit 3 increases the current of the on signal or off signal input to the control electrode of the main three-terminal transistor 1, including:

[0110] The turn-on voltage regulating module increases the voltage of the second three-terminal transistor M off The voltage between the control electrode and the first electrode.

[0111] Furthermore, the shutdown junction temperature control method is specifically:

[0112] When the junction temperature difference ΔT j Less than the first threshold junction temperature Tjth1 When the shutdown voltage regulating module turns off the second three-terminal transistor M off The voltage between the control electrode and the first electrode is adjusted to the second three-terminal transistor M off The minimum allowable voltage V between the control electrode and the first electrode is gsoff,min ;

[0113] When the junction temperature difference ΔT j Greater than the second threshold junction temperature T jth2 When the turn-on voltage regulating module turns the second three-terminal transistor M off The voltage between the control electrode and the first electrode is adjusted to the second three-terminal transistor M off The maximum allowable voltage V between the control electrode and the first electrode is gsoff,max ;

[0114] When the junction temperature difference ΔT j Greater than the first threshold junction temperature T jth1 , and is less than the second threshold junction temperature T jth2 When the turn-on voltage regulating module turns the second three-terminal transistor M off The voltage between the control electrode and the first electrode is proportionally adjusted to the maximum allowable voltage V gsoff,max The minimum allowable shutdown voltage V gsoff,min The corresponding voltage between.

[0115] In a specific embodiment, another junction temperature adjustment method of the driving circuit of the present disclosure is illustrated by way of example; the exemplary configuration of the present disclosure is that the first three-terminal transistor M on , the second three-terminal transistor M off The first terminal of the first three-terminal transistor M on , the second three-terminal transistor M off The second electrode is the drain.

[0116] According to the first three-terminal transistor M on , the second three-terminal transistor M off The gate drive circuit can be divided into two operating modes according to the different conduction degrees. on , the second three-terminal transistor M off They are all called auxiliary three-terminal transistors.

[0117] In the working mode (the current of the maximum on signal or off signal is not reached), during the switching process of the main three-terminal transistor 1, the auxiliary three-terminal transistor (M on 、M off ) works in the linear region and can be equivalent to a resistor. With the auxiliary three-terminal transistor (M on 、Moff )The equivalent resistance is different due to the different degree of conduction.

[0118] At this time, when the bus voltage V DC and load current I L When the main three-terminal transistor 1 is turned on, the loss E on and turn-off loss E off It can be expressed as

[0119]

[0120] Where a, b, c, d are determined by the operating conditions of the main three-terminal transistor 1 and the first three-terminal transistor M on , the second three-terminal transistor M off Characteristics jointly determined by the parameters. V gson is the first three-terminal transistor M on The turn-on gate-source voltage, V thon is the first three-terminal transistor M on The threshold voltage. V gsoff is the second three-terminal transistor M off The turn-off gate-source voltage, V thoff is the second three-terminal transistor M off The threshold voltage.

[0121] In the second working mode (reaching the maximum current of the on-signal or off-signal), during the switching process of the main three-terminal transistor 1, the auxiliary three-terminal transistor (M on 、M off ) works in the saturation region and can be equivalent to a current source.

[0122] See also Figure 2 As shown, in working mode 2, the turn-on waveform of the main three-terminal transistor 1 under the gate drive circuit.

[0123] When the bus voltage V DC and load current I L When the switching loss of the main three-terminal transistor 1 is constant, it can be expressed as:

[0124] E on =A 1 / (V gson -V thon ) 2

[0125] Among them A 1 The main three-terminal transistor 1 and the first three-terminal transistor M on Parameters jointly determined by characteristics.

[0126] See also Figure 3As shown, in working mode 2, the turn-off waveform of the main three-terminal transistor 1 under the gate drive circuit.

[0127] When the bus voltage V DC and load current I L When the switch-off loss of the main three-terminal transistor 1 is constant, it can be expressed as:

[0128] E off =A 2 / (V gsoff -V thoff ) 2 +B 2 / (V gsoff -V thoff )+C 2

[0129] Among them A 2 ,B 2 ,C 2 The main three-terminal transistor 1 is operated by the second three-terminal transistor M off Parameters jointly determined by characteristics.

[0130] From the above formula, we can know that the opening loss E on and turn-off loss E off With auxiliary three-terminal transistor (M on 、M off ) of the gate-source voltage V gs Inversely proportional. Figure 4 , Figure 5 As shown, the turn-on loss E can be obtained through experimental testing. on and turn-off loss E off With auxiliary three-terminal transistor (M on 、M off )'s gate-source voltage V gs The relationship between.

[0131] See also Figure 6 As shown, the controller 312 receives the measured junction temperature T j , and the set reference junction temperature T jref Make a difference and get the junction temperature difference ΔT j , junction temperature difference ΔT j The nonlinear link is based on the junction temperature difference ΔT j And the nonlinear control law outputs the normalized turn-on loss (per unit value) and normalized turn-off loss (per unit value), and then calculate the turn-on gate-source voltage V corresponding to the loss based on the loss model gson and the second three-terminal transistor M off The gate-source voltage V gsoff, realize the corresponding auxiliary three-terminal transistor (M on 、M off ) voltage regulation, thereby achieving real-time regulation of the turn-on and turn-off losses of the main three-terminal transistor 1 and achieving smooth control of the junction temperature.

[0132] in,

[0133]

[0134]

[0135] therefore, When

[0136]

[0137]

[0138] Then, the control strategy can be set as:

[0139] When the junction temperature difference ΔT j Less than the first threshold junction temperature T jth1 When, that is, T j -T jref <T jth1 , indicating that the junction temperature of the main three-terminal transistor 1 is low, and the normalized turn-on loss of this embodiment is and normalized turn-off loss is set to 1, turning on the gate-source voltage V gson and the turn-off gate-source voltage V gsoff is set to the minimum value, reducing the current of the gate turn-on signal or turn-off signal of the main three-terminal transistor 1, and the turn-on and turn-off losses of the main three-terminal transistor 1 are set to the maximum. gson Can be reduced to the minimum allowable turn-on voltage V gson,min , turn-off gate-source voltage V gsoff Can be reduced to the minimum allowable shutdown voltage V gsoff,min .

[0140] When the junction temperature difference ΔT j Greater than the first threshold junction temperature T jth1 , and is less than the second threshold junction temperature T jth2 When, that is, T jth1 <T j -T jref <T jth2 When the normalized turn-on loss and normalized turn-off loss The switching loss of the main three-terminal transistor 1 is reduced, the junction temperature is reduced, and the auxiliary three-terminal transistor (M on 、M off ) of the turn-on gate-source voltage Vgson and the turn-off gate-source voltage V gsoff When it increases in proportion,

[0141] Normalized turn-on loss of this embodiment for:

[0142]

[0143] Normalized turn-off loss of this embodiment for:

[0144]

[0145] When the junction temperature difference ΔT j Greater than the second threshold junction temperature T jth2 When, that is, T jth2 <T j -T jref When the junction temperature of the main three-terminal transistor 1 is high, the normalized turn-on loss and normalized turn-off loss are set to k 1 and k 2 , turn on gate-source voltage V gson and the turn-off gate-source voltage V gsoff is set to the maximum value. At this time, the turn-on and turn-off losses of the main three-terminal transistor 1 are set to the minimum. The turn-on gate-source voltage V gson Can be increased to the maximum allowable voltage V gson,max , turn-off gate-source voltage V gsoff Can be increased to the maximum allowable shutdown voltage V gsoff,max .

[0146] In other embodiments, when the gate drive circuit of the present disclosure is applied in the field of inverter, the maximum allowable voltage V gson,max , Turn off the maximum allowable voltage V gsoff,max , open the minimum allowable voltage V gson,min , minimum allowable shutdown voltage V gsoff,min , minimum opening loss k 1 , minimum turn-off loss k 2 The parameter acquisition method is as follows:

[0147] In terms of life span, according to the LESIT model, the remaining power cycle number (proportional to life span) of the power device is N f satisfy:

[0148]

[0149] Where, T jm is the average junction temperature, A and α are fitting parameters, A = 302500K-α ,α= -5.03, activation energy E a =9.89×10 -20 J, Boltzmann constant k b =1.38×10 -23 J / K.

[0150] In the above formula, the life of the power device is affected by the average junction temperature T jm Also affected by the junction temperature difference ΔT j , and therefore need to be controlled separately.

[0151] In terms of safety of junction temperature control, the factors that need to be considered are dead time and gate current oscillation. In terms of dead time, in order to prevent the upper and lower transistors of the same bridge arm from being directly connected, the turn-off time of the main three-terminal transistor 1 should meet the following requirements:

[0152] t off (V gsoff,min ,i L,max )≤t dead

[0153] Where, t dead is the dead time, t off is the turn-off time of the main three-terminal transistor 1, where t off It is defined as the time from the beginning to the end of the shutdown, that is, Figure 3 Medium 6 to 10 Time. off is about the turn-off gate-source voltage V gsoff and load current i L Function of t off With the turn-off gate-source voltage V gsoff In order to ensure the safety of the tube, it is necessary to ensure that the load current reaches the maximum value i L.max In this case, no direct pass occurs.

[0154] In the actual circuit, there is parasitic inductance in the gate loop of the main three-terminal transistor 1. When the switching speed of the main three-terminal transistor 1 is too fast, the gate current will oscillate, affecting the safe operation of the main three-terminal transistor 1. To avoid the occurrence of gate current oscillation, the gate-source voltage V gson and the turn-off gate-source voltage V gsoff The value of should also satisfy:

[0155]

[0156] In the formula, R ds(on)on is the first three-terminal transistor M on The on resistance, R ds(on)offThe second three-terminal transistor M off The on-resistance, V gson,max is the maximum allowable voltage for opening, L g is the parasitic inductance of the control loop of the main three-terminal transistor, C iss is the input capacitance of the main three-terminal transistor; through the above formula, the maximum allowable turn-on voltage V gson,max , Turn off the maximum allowable voltage V gsoff,max .

[0157] In terms of system efficiency, for a three-phase two-level inverter that outputs a sinusoidal voltage and current, the switching loss of one transistor is P sw satisfy:

[0158]

[0159] In the formula, f sw is the switching frequency, I RMS is the rated current, I REF is the current reference value, V REF is the voltage reference value, V DC is the bus voltage, E on and E off They are the standard turn-on loss and the standard turn-off loss of the transistor, which can be calculated by REF As bus voltage, I REF Obtained as a double pulse test at load current conditions, available in the device data sheet.

[0160] In order to prevent the junction temperature control method from seriously affecting the inverter efficiency, the loss under the junction temperature control method should meet the following requirements:

[0161] P sw，max (V gson,min ,V gsoff,min )≤k·P sw_nom

[0162] Where P sw，max is the switching loss of the junction temperature control method disclosed in the present invention, P sw_nom is the switching loss under direct drive of the driver transistor, k (k>1) is the loss limiting factor, which is determined by the life extension requirement and efficiency requirement.

[0163] Junction temperature control method In terms of inverter output nonlinearity, the inverter output voltage usually has distortion, and this voltage distortion can be expressed as:

[0164] V err =(f sw V DC (t off -t on)) / 2

[0165] Where V err is the inverter output voltage distortion, f sw is the switching frequency, V DC is the bus voltage, t off is the turn-on delay time of the main three-terminal transistor 1, t on is the turn-off delay time of the main three-terminal transistor 1. The inverter output voltage distortion will cause output current harmonics, which need to be suppressed. Therefore, the gate-source voltage V gson and the turn-off gate-source voltage V gsoff Need to meet:

[0166]

[0167] Therefore, the minimum allowable voltage V gson,min and the minimum allowable shutdown voltage V gsoff,min It is determined based on the output voltage nonlinearity allowable coefficient m of the main three-terminal transistor.

[0168] See also Figure 7 As shown, the gate drive circuit and junction temperature control method of the present invention are applied, and the bus voltage is 200V, the drive voltage is +15V / -5V, and the switching frequency is 20kHz. The traditional drive circuit and the proposed active junction temperature control system are used for experiments. Figure 7 It can be seen that during the load current fluctuation between 18 seconds and 72 seconds, the junction temperature fluctuation dropped from 11.6°C to 8.8°C, a decrease of 24.1%, by adopting the designed junction temperature control strategy. The designed junction temperature control strategy reduces the remaining power cycle number N of the SiC MOSFET to f From 4.13×10 9 Increased to 1.62×10 10 , increased by 3.92 times. In addition, by adopting the gate drive circuit disclosed in the present invention, when applied to an inverter, the power consumption is reduced by 4.15%.

[0169] In addition, the gate drive circuit disclosed in the present invention can be used in a variety of applications that require adjustment of switching speed and switching loss.

[0170] When the junction temperature difference is less than the preset first threshold current I th1 When, that is, II ref th1 ​When the load junction temperature is low and the conduction loss is small, the controller 312 increases the voltage of the control electrode of the auxiliary three-terminal transistor M; the conduction degree of the auxiliary three-terminal transistor M increases, the shunt current of the execution circuit 32 increases, the gate current of the main three-terminal transistor 1 decreases, and the turn-on loss increases to compensate for the decrease in junction temperature caused by the decrease in load current. The controller 312 can increase the control electrode voltage of the auxiliary three-terminal transistor M to a preset first voltage V gs1_high The voltage of the control electrode of the auxiliary three-terminal transistor M can also be increased in a gradient manner.

[0171] When the junction temperature difference is greater than the preset second threshold current I th2 , that is, II ref >I th2 When the load junction temperature is high and the conduction loss is large, the controller 312 reduces the control electrode voltage of the auxiliary three-terminal transistor M. The conduction degree of the three-terminal transistor M is reduced, the shunt current of the execution circuit 32 is reduced, the gate current of the main three-terminal transistor 1 is increased, and the turn-on loss is reduced to compensate for the junction temperature rise caused by the increase in load current. The controller 312 reduces the control electrode voltage of the auxiliary three-terminal transistor M to a preset second voltage V gs1_low The voltage of the control electrode of the auxiliary three-terminal transistor M can also be reduced in a gradient manner.

[0172] Combination Figure 4 , Figure 5 As shown, in the technical solution of this embodiment, under the test conditions of 200V bus voltage and 10A load current, the opening loss adjustment range of the junction temperature regulation circuit disclosed in the present invention is 125.8μJ to 549.78μJ, which can achieve continuous adjustment in a wide range.

[0173] Under the conditions of bus voltage 200V and switching frequency 40kHz, when the load current effective value switches between 1.3A and 4A, the junction temperature fluctuation is reduced from 16.9°C to 11.2°C by adopting the technical solution disclosed in the present invention, which is a reduction of 33.7%. The number of remaining power cycles (proportional to the life) of the main three-terminal transistor 1 is N f From 4.94×10 8 Increased to 3.42×10 9 , which is improved by 6.92 times. Among them, parameter I ref 2.5A,I th1 -0.5A, I th2 0.5A, V gs1_high is 4.5V, V gs1_low is 2V.

[0174] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0175] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying 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 the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0176] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A gate drive circuit, characterized in that: include: A main three-terminal transistor, based on the received turn-on signal or turn-off signal, turns on or turns off the main three-terminal transistor; a junction temperature control circuit connected to the control electrode of the main three-terminal transistor, for obtaining a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature on the main three-terminal transistor when the main three-terminal transistor is turned on; when the junction temperature difference is less than a preset first threshold junction temperature, reducing the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; and when the junction temperature difference is greater than a preset second threshold junction temperature, increasing the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; the second threshold junction temperature is greater than or equal to the first threshold junction temperature; The junction temperature control circuit comprises: A signal feedback circuit is connected to the main three-terminal transistor, obtains a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature on the main three-terminal transistor, compares the junction temperature difference with a first threshold junction temperature or a second threshold junction temperature, and sends a control signal to the execution circuit according to the comparison result; an execution circuit, connected to the control electrode and the signal feedback circuit of the main three-terminal transistor respectively, and configured to reduce the current of the on signal or off signal input to the control electrode of the main three-terminal transistor or increase the current of the on signal or off signal input to the control electrode of the main three-terminal transistor according to the control signal; The execution circuit includes an opening control circuit and a closing control circuit. The signal feedback circuit is connected to the control electrode of the main three-terminal transistor through the turn-on control circuit; The signal feedback circuit is connected to the control electrode of the main three-terminal transistor through the shutdown control circuit; The turn-on control circuit includes a turn-on voltage regulating module, a first three-terminal transistor, a first diode and a first capacitor. The input end of the turn-on voltage regulating module is connected to the signal feedback circuit; the first output end of the turn-on voltage regulating module is connected to the control electrode of the first three-terminal transistor, and the second output end of the turn-on voltage regulating module is connected to the first electrode of the first three-terminal transistor; The first electrode of the first three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a first diode; the second electrode of the first three-terminal transistor is an input end of an on signal; The control electrode of the first three-terminal transistor is connected to the first electrode of the first three-terminal transistor through the first capacitor.

2. The gate drive circuit according to claim 1, wherein: The shutdown control circuit includes a shutdown voltage adjustment module, a second three-terminal transistor, a second diode and a second capacitor. The input end of the shutdown voltage regulation module is connected to the signal feedback circuit; the first output end of the shutdown voltage regulation module is connected to the control electrode of the second three-terminal transistor, and the second output end of the shutdown voltage regulation module is connected to the first electrode of the second three-terminal transistor; The second electrode of the second three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a second diode; the first electrode of the second three-terminal transistor is an input end of a shutdown signal; The control electrode of the second three-terminal transistor is connected to the first electrode of the second three-terminal transistor through the second capacitor.

3. The gate drive circuit according to claim 1 or 2, characterized in that: The signal feedback circuit comprises: a sensor connected to the main three-terminal transistor and configured to detect a measured junction temperature on the main three-terminal transistor; A controller is connected to the sensor, the turn-on control circuit and the turn-off control circuit respectively. The controller is used to obtain a junction temperature difference between a measured junction temperature and a preset reference junction temperature based on a measured junction temperature on the main three-terminal transistor, compare the junction temperature difference with a first threshold junction temperature or a second threshold junction temperature, and send a control signal to the execution circuit according to the comparison result.

4. The gate drive circuit according to claim 3, wherein: The controller is connected to the voltage regulation module through a digital isolator.

5. A junction temperature control method based on the gate drive circuit according to claim 1 or 2, characterized in that: The main three-terminal transistor is turned on or off under the control of an on signal or an off signal; The junction temperature control circuit acquires the measured junction temperature on the main three-terminal transistor, and obtains a junction temperature difference between the measured junction temperature and a preset reference junction temperature based on the measured junction temperature; When the junction temperature difference is less than a preset first threshold junction temperature, the junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; when the junction temperature difference is greater than a preset second threshold junction temperature, the junction temperature control circuit increases the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor; wherein the second threshold junction temperature is greater than or equal to the first threshold junction temperature.

6. The junction temperature control method according to claim 5, characterized in that: The junction temperature control circuit includes a signal feedback circuit and an on-control circuit connected to the signal feedback circuit, wherein the on-control circuit includes an on-voltage regulating module, a first three-terminal transistor, a first diode and a first capacitor; The input end of the turn-on voltage regulating module is connected to the signal feedback circuit; the first output end of the turn-on voltage regulating module is connected to the control electrode of the first three-terminal transistor, and the second output end of the turn-on voltage regulating module is connected to the first electrode of the first three-terminal transistor; the first electrode of the first three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a first diode; the second electrode of the first three-terminal transistor is the input end of the shutdown signal; the control electrode of the first three-terminal transistor is connected to the first electrode of the first three-terminal transistor through the first capacitor; The junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor, including: The turn-on voltage regulating module reduces the voltage between the control electrode and the first electrode of the first three-terminal transistor; The junction temperature control circuit increases the current of the on signal or the off signal input to the control electrode of the main three-terminal transistor, including: The turn-on voltage regulating module increases the voltage between the control electrode and the first electrode of the first three-terminal transistor.

7. The junction temperature control method according to claim 5, characterized in that: The junction temperature control circuit includes a signal feedback circuit and a shutdown control circuit connected to the signal feedback circuit, wherein the shutdown control circuit includes a shutdown voltage adjustment module, a second three-terminal transistor, a second diode and a second capacitor. The input end of the shutdown voltage regulating module is connected to the signal feedback circuit; the first output end of the shutdown voltage regulating module is connected to the control electrode of the second three-terminal transistor, and the second output end of the shutdown voltage regulating module is connected to the first electrode of the second three-terminal transistor; the second electrode of the second three-terminal transistor is also connected to the control electrode of the main three-terminal transistor through a second diode; the first electrode of the second three-terminal transistor is the input end of the shutdown signal; the control electrode of the second three-terminal transistor is connected to the first electrode of the second three-terminal transistor through the second capacitor; The junction temperature control circuit reduces the current of the turn-on signal or the turn-off signal input to the control electrode of the main three-terminal transistor, including: The off voltage regulating module reduces the voltage between the control electrode and the first electrode of the second three-terminal transistor; The junction temperature control circuit increases the current of the on signal or the off signal input to the control electrode of the main three-terminal transistor, including: The turn-off voltage regulating module increases the voltage between the control electrode and the first electrode of the second three-terminal transistor.

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