Online monitoring and driving circuit, junction temperature calculation method and system for press-fit IGBT

Abstract

This application belongs to the field of IGBT junction temperature monitoring, and specifically discloses an online monitoring and driving circuit, a junction temperature calculation method and system for press-fit IGBTs. Through this application, the virtual threshold voltage can be accurately monitored online within one switching cycle (100μs) of the PP IGBT without affecting the normal operation of the power converter; there is no need to open the IGBT package, and the monitoring circuit can be directly connected to the device port to achieve non-invasive monitoring. The virtual threshold voltage is used as a new temperature-sensitive electrical parameter (TSEP). By accurately monitoring the virtual threshold voltage online, the junction temperature is calculated online based on the linear relationship between the virtual threshold voltage and the junction temperature. The following technical effects are achieved: 1) Short response time: within one switching cycle (100μs); 2) Compared with traditional methods, the number of monitoring circuit elements is small; 3) It is applicable to any pressure situation, and it only needs to calibrate the fitting relationship of the junction temperature-virtual threshold voltage under the pressure.

Description

Technical Field

[0001] The present application belongs to the technical field of IGBT junction temperature monitoring, and more specifically, relates to an online monitoring and driving circuit, a junction temperature calculation method and a system for press-fit IGBTs. Background Art

[0002] Press-fit packaged insulated gate bipolar transistors (PP IGBTs) are widely used in flexible DC converter valves, high-voltage DC circuit breakers, and static synchronous compensators. Compared with traditional solder-packaged IGBTs, PP IGBTs offer advantages such as high power density, double-sided cooling, low parasitic inductance, ease of series connection, and fault short-circuit resistance. As the most vulnerable component in power conversion systems, the reliability of PP IGBTs has attracted widespread attention. Among the various failure factors of power semiconductors, overheating accounts for the highest proportion. Online monitoring of PP IGBT junction temperature (i.e., the actual operating temperature of the power semiconductor IGBT in power electronic power converters) can help extend device life and improve maintenance strategies for flexible DC transmission systems.

[0003] Existing junction temperature monitoring methods can be divided into: physical contact method, optical non-contact method, thermal impedance model prediction method and temperature sensitive electrical parameter (TSEP) method. Thermosensitive electrical parameters refer to device electrical parameters that have a certain functional relationship with the temperature of the power semiconductor chip. Compared with the other three methods, the TSEP method has the advantages of short response time, non-invasiveness and easy online monitoring, but there are few studies on online monitoring of PP IGBT junction temperature based on TSEP. Due to the complexity of the press-fit packaging structure, traditional IGBT junction temperature monitoring methods are difficult to monitor the T of PP IGBT online. j . Summary of the Invention

[0004] In response to the defects of the existing technology, the purpose of this application is to provide an online monitoring and driving circuit, a junction temperature calculation method and system for press-fit IGBTs, aiming to solve the problem that traditional IGBT junction temperature monitoring methods are difficult to monitor the junction temperature of PP IGBTs online.

[0005] To achieve the above objectives, in a first aspect, the present application provides a pressure-contact IGBT virtual threshold voltage online monitoring circuit, comprising: a current source, two diodes and three MOSFETs; wherein,

[0006] The output end of the current source, the drain of the first MOSFET and the drain of the second MOSFET are short-circuited;

[0007] The source of the first MOSFET is grounded, and the source of the second MOSFET, the anode of the first diode, and the anode of the second diode are short-circuited;

[0008] The cathode of the first diode is used to be connected to the collector of the press-connected IGBT under test, and the emitter of the press-connected IGBT under test is grounded;

[0009] The cathode of the second diode is connected to the source of the third MOSFET, which is used to be connected to the gate of the tested pressure-connected IGBT;

[0010] The drain of the third MOSFET is used to be connected to the output port of the external gate drive circuit.

[0011] Preferably, the output voltage of the current source is greater than the threshold voltage of the pressure-conducting IGBT, and the output current is in the mA to nA level.

[0012] Preferably, the diode is a PiN diode, and the MOSFET is a Si MOSFET.

[0013] Preferably, it also includes: a first control module, which is used to control the first MOSFET and the third MOSFET to remain closed and the second MOSFET to remain open when the monitoring function is disabled; and to control the first MOSFET and the third MOSFET to remain open and the second MOSFET to remain closed when the monitoring function is enabled.

[0014] To achieve the above objectives, in a second aspect, the present application provides a gate drive circuit for a crimped IGBT, wherein the gate drive circuit integrates the online monitoring circuit as described in the first aspect; wherein the drain of the third MOSFET is connected to the output port of the gate drive circuit.

[0015] Preferably, it also includes a second control module for controlling the output signal switch of the gate drive circuit through a PWM signal; after a delay of 1 microsecond to 2 microseconds after the falling edge of a certain PWM signal, the monitoring function of the monitoring circuit is turned on; during the monitoring period, after the collector current of the crimped IGBT reaches a preset threshold, the virtual threshold voltage of the crimped IGBT is collected multiple times and the average is calculated, and the average is used as the virtual threshold voltage monitoring result; after a sudden change occurs in the collected value of the virtual threshold voltage of the crimped IGBT, the monitoring function of the monitoring circuit is turned off.

[0016] To achieve the above objectives, in a third aspect, the present application provides a power electronic power converter, comprising the press-fit IGBT gate drive circuit as described in the second aspect.

[0017] To achieve the above objectives, in a fourth aspect, the present application provides a method for calculating the junction temperature of a press-fit IGBT based on a virtual threshold voltage, comprising:

[0018] Calibrate the fitting relationship between the junction temperature and virtual threshold voltage of the target press-fit IGBT under the current pressure, wherein the virtual threshold voltage data during the calibration process is obtained by monitoring the press-fit IGBT virtual threshold voltage online monitoring circuit as described in the first aspect;

[0019] The virtual threshold voltage monitored in real time is substituted into the fitting equation to obtain the current junction temperature.

[0020] To achieve the above objectives, in a fifth aspect, the present application provides a system for calculating junction temperature of a press-fit IGBT based on a virtual threshold voltage, comprising at least one processor and at least one memory;

[0021] The at least one memory is for storing computer instructions;

[0022] The at least one processor is used to execute at least part of the computer instructions to implement the junction temperature calculation method described in the fourth aspect.

[0023] Preferably, the system obtains the junction temperature data during the calibration process by the following method, specifically:

[0024] Dig a groove on the side of the emitter Mo sheet close to the surface of the IGBT chip;

[0025] Use adhesive to fix the thermocouple in the groove gap of the emitter Mo sheet;

[0026] The voltage signal of the thermocouple is transmitted to a digital thermometer to obtain the surface temperature of the press-fit IGBT emitter.

[0027] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0028] (1) The present application provides an online monitoring circuit for the virtual threshold voltage of a press-fit IGBT, comprising: a current source, two diodes, and three MOSFETs; the output end of the current source, the drain of the first MOSFET, and the drain of the second MOSFET are short-circuited; the source of the first MOSFET is grounded, and the source of the second MOSFET, the anode of the first diode, and the anode of the second diode are short-circuited; the cathode of the first diode is used to connect to the collector of the press-fit IGBT under test, and the emitter of the press-fit IGBT under test is grounded; the cathode of the second diode is connected to the source of the third MOSFET, which is used to connect to the gate of the press-fit IGBT under test; and the drain of the third MOSFET is used to connect to the output port of an external gate drive circuit. The present application can accurately monitor the virtual threshold voltage online within one switching cycle (100μs) of the PP IGBT without affecting the normal operation of the power converter.

[0029] (2) The present application provides a gate drive circuit for a press-fit IGBT, which integrates an online monitoring circuit into the press-fit IGBT gate driver. The monitoring circuit can be directly connected to the device port without opening the IGBT package, thereby achieving non-invasive monitoring.

[0030] (3) This application provides a method and system for calculating the junction temperature of a press-fit IGBT based on virtual threshold voltage. The virtual threshold voltage is used as a new temperature-sensitive electrical parameter (TSEP). The virtual threshold voltage is accurately monitored online, and then the junction temperature is calculated online based on the linear relationship between the virtual threshold voltage and the junction temperature. The above method achieves the following technical effects: 1) Short response time: within one switching cycle (100μs); 2) Compared with traditional methods, the number of monitoring circuit elements is small; 3) It is applicable to any pressure condition, and only the fitting relationship between the junction temperature and the virtual threshold voltage under the pressure needs to be calibrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a schematic diagram of the virtual threshold voltage measurement principle provided in an embodiment of the present application, wherein (a) corresponds to before the conductive channel is formed, and (b) corresponds to after the conductive channel is formed.

[0032] Figure 2 It is V provided in the embodiment of this application v,th LTspice simulation of the relationship with temperature, where (a) is the simulation circuit and (b) is the simulation result.

[0033] Figure 3 The embodiment of the present application provides a half-bridge inverter topology with a gate circuit having an integrated virtual threshold voltage monitoring circuit.

[0034] Figure 4 The V in different time periods provided in the embodiments of this application is v,th The operating modes of the monitoring circuit, where (a) corresponds to before time t1 and after time t4, (b) corresponds to the time period from t1 to t2, (c) corresponds to the time period from t2 to t3, and (d) corresponds to the time period from t3 to t4.

[0035] Figure 5 This is the online monitoring V provided by the embodiment of the present application v,th Timing diagram of .

[0036] Figure 6 This is a schematic diagram of the junction temperature online monitoring and verification process provided in an embodiment of the present application.

[0037] Figure 7 This is the finite element simulation result of temperature provided in the embodiment of the present application.

[0038] Figure 8This is a half-bridge inverter experimental device with the proposed circuit provided in an embodiment of the present application.

[0039] Figure 9 This is an IGBT submodule assembly with a thermocouple provided in an embodiment of the present application.

[0040] Figure 10 This is an emitter molybdenum sheet with a thermocouple provided in an embodiment of the present application, wherein (a) is the measurement result using a stereo microscope, and (b) is the measurement result using a laser confocal microscope.

[0041] Figure 11 This is an assembly diagram of an IGBT submodule with a thermocouple provided in an embodiment of the present application, wherein (a) is a front view and (b) is a top view.

[0042] Figure 12 This is a half-bridge PP IGBT module under different pressures provided by the embodiments of the present application, wherein (a) corresponds to a pressure of 0.31 kN and (b) corresponds to a pressure of 4.30 kN.

[0043] Figure 13 The experimental results provided in the embodiment of the present application are obtained under a pressure of 0.31 kN and a bus voltage of 300 V, wherein (a) represents I load ,V ge ,V ce and I ce Experimental waveform, (b) shows the temperature results.

[0044] Figure 14 The experimental results provided in the embodiment of the present application are obtained under a pressure of 0.31 kN and different bus voltages, wherein (a) represents I load and V ge Experimental waveform, (b) shows the temperature results.

[0045] Figure 15 The embodiment of the present application provides the V-based v,th Online junction temperature monitoring experimental results, where (a) corresponds to a pressure of 0.31 kN and (b) corresponds to a pressure of 4.30 kN. DETAILED DESCRIPTION

[0046] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of this application are explained and described below.

[0047] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0048] Virtual threshold voltage V v,th The measurement principle is as follows Figure 1 shown.

[0049] First, if Figure 1As shown in (a), the current source S a1 Through the diode D a1 The IGBT gate-emitter capacitance is charged. Under the action of the gate oxide electric field, holes gather on the lower surface of the gate oxide. The accumulated holes attract a large number of electrons to gather on the upper surface of the p-type layer, forming a conductive channel. After the conductive channel is formed, S a1 Start from D a1 Commutation to diode D a2 .

[0050] The virtual threshold voltage is measured when the gate voltage is not equal to the collector voltage. a1 The current to the emitter is mainly through D a2 Form a closed path, such as Figure 1 As shown by the arrow in (b). Therefore, no current flows through D a1 Due to D a2 In the presence of forward voltage, the gate voltage is greater than the collector voltage. According to the virtual threshold voltage measurement principle, the virtual threshold voltage can form an inversion layer in the p-type layer. V v,th and the IGBT's body potential ψ B The body potential depends on the intrinsic concentration n of the IGBT. i . V v,th The temperature dependence of n i Results of thermal dependence.

[0051] n i It can be expressed as the following formula:

[0052]

[0053] Where T represents the IGBT chip temperature, N represents the effective state density, and α2 and γ are fitting coefficients and are constants.

[0054] To study V v,th As a feasibility study of TSEP, a V v,th Monitoring circuits, such as Figure 2 As shown in (a), 9V represents a voltage source, LT3092 is a current source, and FR2YSMA is a diode. This application studies the virtual threshold voltage V of two IGBT devices with different rated currents. v,th and junction temperature T j The relationship between Figure 2 As shown in (b), the fitting results show good linearity.

[0055] In order to calculate the PP IGBT junction temperature online, it is necessary to measure V without disturbing the normal operation of the converter. v,th .like Figure 3As shown, the proposed V v,th The monitoring circuit can be integrated into the gate driver and then connected to the half-bridge inverter. In order not to interfere with the normal operation of the converter, V v,th The monitoring circuit adds some auxiliary switches (MOSFETM1, M2 and M3).

[0056] like Figure 4 As shown in (a) to (d), the proposed V v,th The online monitoring circuit includes a current source S1, two diodes D3 and D4, and three Si MOSFETs M1, M2, and M3. The output of current source S1, the drain of M1, and the drain of M2 are short-circuited; the source of M1 is grounded, and the source of M2, the anode of D3, and the anode of D4 are short-circuited; the cathode of D3 is connected to the collector of the external IGBT device under test; the cathode of D4, the source of M3, and the gate of the external IGBT device under test are connected; the drain of M3 is connected to the output port of the external gate driver board; and the emitter of the external IGBT device under test is grounded.

[0057] At the control level, the gate control signals of MOSFETM1 and M2 are interlocked, and the gate control signals of MOSFETM1 and M3 are the same.

[0058] In order to achieve V v,th For accurate measurement, a proper monitoring circuit should be designed. The selection of circuit components is discussed below.

[0059] 1) Selection of current source: The function of the current source is to charge the gate-emitter capacitance of the IGBT to form a conductive channel. Since the threshold voltage of the IGBT is high, the current source needs to output a higher voltage. In order to reduce power loss, the current source needs to output a smaller current. The current source used is implemented by LT3092, such as Figure 2 As shown in (a) of the figure, according to the LT3092 datasheet, the constant current can be changed by adjusting two resistors at the SET and OUT pins. The output voltage range is very wide, including the threshold voltage of the IGBT.

[0060] 2) Diode selection: When the IGBT is in the off state, the diode needs to block the high collector-emitter voltage. In addition, the diode's forward voltage should be as small as possible, and a PiN diode is recommended.

[0061] 3) MOSFET selection: MOSFETs need to provide current freewheeling and fast switching. MOSFETs do not need to block high voltages, and standard MOSFETs can meet these requirements.

[0062] In order to better understand the principle of the virtual threshold voltage online monitoring method, combined with Figure 5 The sequence diagram shown is used for explanation.

[0063] Time t1: G1 falling edge delay 1μs~2μs;

[0064] Time t2: The next rising edge of G1 arrives;

[0065] Time t3: The IGBT collector current reaches a preset threshold, for example, 1A;

[0066] Time t4: The collected value of the virtual threshold voltage of the press-connected IGBT suddenly changes.

[0067] exist Figure 5 Before time t1 and after time t4, the virtual threshold voltage monitoring function is disabled. When disabled, M1 and M3 always remain closed, and M2 always remains open. During periods t1 to t4 (referred to as the "control period" and not exceeding the switching period), the virtual threshold voltage monitoring function is enabled. When enabled, M1 and M3 always remain open, and M2 always remains closed.

[0068] exist Figure 5 Before time t1 and after time t4, S1 forms a closed circuit through M1, as shown in Figure 4 As shown in (a), M2, which remains open, electrically isolates S1 from the device under test (DUT).

[0069] exist Figure 5 In the t1~t2 period, S1 charges the gate-emitter capacitance of the DUT through M2 and D4, as shown in Figure 4 As shown in (b). Because the output signal G1 of the gate driver board is at a low level and the gate driver outputs a negative voltage V in the t1~t2 stage ee , so the body diode of M3 is forward biased. The gate-emitter voltage V ge clamped to negative voltages.

[0070] exist Figure 5 During the t2~t3 period, G1 is at a high level and the gate driver outputs a positive voltage V cc The body diode of M3 is reverse biased. S1 continues to charge the gate-emitter capacitance of the DUT until a conducting channel is formed, such as Figure 4 As shown in (c). When a conductive channel is formed, V ge Equal to V v,th .

[0071] exist Figure 5 In the t3~t4 stage, the DUT conductive channel has been formed. S1 forms a closed circuit through M2, D3 and DUT, as shown in Figure 4 As shown in (d). Because the gate driver has already output V cc, so when M3 switches to the closed state, the DUT gate-emitter voltage is pulled up to V cc In addition, after the conductive channel is formed, the load current also flows through the collector of the DUT. Due to the transfer characteristics of the DUT, the gate-emitter voltage is affected by the load current. In order to avoid the influence of the load current on the gate-emitter voltage, V is obtained at a specific current. v,th .

[0072] This application proposes a T j Online calculation and verification methods, such as Figure 6 When the press-fit IGBT is heated under the load current of the converter, the V v,th , and then the measured V v,th Substitute into the fitting formula to calculate the T of the press-mounted IGBT j .

[0073] In this embodiment, the fitting relationship between junction temperature and virtual threshold voltage at 0.31 kN is:

[0074] T j =-139.9088*V v,th +1036.29217;

[0075] The fitting relationship between junction temperature and virtual threshold voltage under 4.30kN is:

[0076] T j =-185.03378*V v,th +1336.40068.

[0077] In addition, a chip reference temperature is provided by a physical contact method. A groove is dug on the side of the emitter Mo sheet close to the IGBT chip. A thermocouple is built into the groove of the emitter Mo sheet. The voltage signal of the thermocouple is transmitted to a digital thermometer to obtain the emitter surface temperature (T E_Mo ). By calculating T j and T E_Mo The difference ΔT between them is used to verify the accuracy of the proposed method.

[0078] Finite element modeling was used to analyze the difference between the thermocouple-measured temperature and the junction temperature. To accurately simulate chip self-heating, the active area of ​​the IGBT chip was modeled. The dimensions of the chip's active area were measured using a Stemi508 stereo microscope. The material parameters and dimensions of the components are shown in Table 1. Ф represents diameter, S represents the active area, and φ represents the active area. a Represents the active area of ​​the IGBT chip. The dimensions of the components used in the simulation are consistent with those used in the experiment.

[0079] Table 1 Material parameters and dimensions of press-fit IGBT components in finite element simulation

[0080]

[0081] The boundary conditions are set as follows: the active area of ​​the IGBT chip is set as the heat source, and its heat generation rate is set to 5W / mm 3 , double-sided heat dissipation is adopted, and the convection heat transfer coefficient of the collector Cu and emitter Cu surfaces is set to 0.02W / (mm 2 ·K).

[0082] Thermal simulation results are as follows Figure 7 As shown, because the thermocouple is sealed inside the adhesive, along Figure 7 A cross section is cut out at point O in the figure. According to the cross-sectional thermal simulation results, it is found that within a depth of 0.25 mm from the surface of the IGBT chip, the temperature of the adhesive is relatively close to the temperature of the IGBT chip.

[0083] The experimental setup of the half-bridge inverter based on the proposed circuit is as follows Figure 8 As shown in the figure, the hydraulic press uses an oil-filled hydraulic cylinder to generate a compressive force, which applies pressure to the PP IGBT. The pressure is displayed by the pressure sensor. The specifications of the experimental components are shown in Table 2. The PWM signal is generated by the DSP TMS320F28335, generating a sinusoidal signal with a frequency of 50Hz. The collector-emitter current I ce The current is measured by a Pearson 3972 current sensor. An oscilloscope MDO3054 with a bandwidth of 500 MHz is selected to capture and record the waveform. The measurement period of the thermocouple is 1 s.

[0084] Table 2 Experimental component specifications

[0085]

[0086]

[0087] IGBT submodule components with thermocouples such as Figure 9 As shown in the figure, a narrow groove about 500 μm deep is dug on the emitter molybdenum sheet, and a thermocouple with a solder point diameter of less than 0.3 mm is placed in it.

[0088] Fix the thermocouple in the emitter molybdenum sheet using a quick-drying adhesive such as Figure 10 As shown in (a) to (b), the position of the thermocouple was measured using a Stemi 508 stereo microscope and a VK-X200K laser confocal microscope. The thermocouple was located at a position with a length of 4.85 mm, a width of 4.39 mm, and a depth of 0.59 μm.

[0089] After assembling the IGBT submodule with the thermocouple, place it on the copper boss with the gate PCB, as shown in the following figure: Figure 11 As shown in (a) to (b) in the figure. Afterwards, the PP IGBT devices are assembled into a half-bridge PP IGBT module, which includes a pressure sensor, some pressure balancing components and two PP IGBT devices, as shown in Figure 12 As shown in (a) to (b).

[0090] The feasibility of the proposed junction temperature online monitoring method was verified online through a half-bridge inverter. The experimental results are as follows: Figure 13 As shown in (a) to (b) in Figure 2, under a load current waveform of two cycles, the operation of the half-bridge inverter is not affected by V v,th Monitor the circuit's impact.

[0091] V v,th The waveform expansion after the monitoring function is enabled, the experimental results show that V ge Changing trends and Figure 5 V ge Consistent. Load current I load , gate-emitter voltage V ge , collector-emitter current V ce , collector-emitter current I ce and auxiliary signal V aux The waveform is as Figure 13 As shown in (a). To avoid signal conflict, a time delay is set between the gate signals of the auxiliary switch MOSFET. After the junction temperature monitoring function is enabled, when the upper bridge IGBT is in the on state and the lower bridge IGBT is in the off state, V ge is clamped to a negative voltage. Then, the anti-parallel diode of the lower bridge enters the freewheeling phase, during which the current flows in the opposite direction. When the gate drive output of the lower bridge IGBT is V cc When V ge Pulled up to V v,th .

[0092] During the operation of the half-bridge inverter, the junction temperature is sampled by a thermocouple, such as Figure 13 As shown in (b), as the operating time of the half-bridge inverter increases, the T j Gradually stabilizes. In order to reduce power consumption, the operating time of the half-bridge inverter is set to 40s. j After gradually stabilizing, at the same time, V v,th and T j Sampling is performed to establish V v,th and T j The relationship between them.

[0093] The experimental results under different bus voltages and 0.31kN pressure are as follows: Figure 14 As shown in (a) to (b), the bus voltage is set to 150V, 250V, 300V, 350V and 400V respectively, and the operation time of the half-bridge inverter is set to 40s. After running for 40 seconds, the half-bridge inverter stops running and the device cools to room temperature. v,th and T j Take samples.

[0094] I load and V ge The waveform is as follows Figure 14 As shown in (a), due to the self-heating effect, the PP IGBT is heated to different temperatures at different load currents, as shown in Figure 14 As shown in (b). When the conductive channel is formed, the load current will flow through the collector. ce Increase, V ge It will also increase according to the IGBT transfer characteristics. In order to avoid the load current on V v,th The effect of the load current on V v,th Sampling, such as Figure 14 As shown in (a). j Increase, V v,th Reduce, such as Figure 14 As shown in (a).

[0095] By fitting the measurement results, V was established at different pressures. v,th and T j The relationship between Figure 15 As shown in (a) to (b). Figure 15 The experimental results can be analyzed to get V v,th and T j There is a good linear relationship between them. In order to verify the proposed v,th The effectiveness of the junction temperature monitoring method is tested. Six experimental results with junction temperature distribution in different temperature ranges are used as the validation data set. The error of the junction temperature monitoring results is shown in Table 3. j Refers to the junction temperature measured by the thermocouple, calculate T j Refers to V v,th Calculated junction temperature. Based on V v,th The junction temperature monitoring results show that the proposed method is effective and the absolute error is within 2.5℃.

[0096] Table 3 Junction temperature monitoring result error

[0097]

[0098] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0099] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0100] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0101] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A crimped IGBT virtual threshold voltage online monitoring circuit, characterized in that: include: A current source, two diodes, and three MOSFETs; where The output end of the current source, the drain of the first MOSFET and the drain of the second MOSFET are short-circuited; The source of the first MOSFET is grounded, and the source of the second MOSFET, the anode of the first diode, and the anode of the second diode are short-circuited; The cathode of the first diode is used to be connected to the collector of the press-connected IGBT under test, and the emitter of the press-connected IGBT under test is grounded; The cathode of the second diode is connected to the source of the third MOSFET, which is used to be connected to the gate of the tested pressure-connected IGBT; The drain of the third MOSFET is used to be connected to the output port of the external gate drive circuit.

2. The online monitoring circuit according to claim 1, characterized in that: The output voltage of the current source is greater than the threshold voltage of the pressed IGBT, and the output current is in the mA to nA level.

3. The online monitoring circuit according to claim 1, wherein: The diode is a PiN diode, and the MOSFET is a SiMOSFET.

4. The online monitoring circuit according to any one of claims 1 to 3, characterized in that: Also includes: The first control module is configured to control the first MOSFET and the third MOSFET to remain closed and the second MOSFET to remain open when the monitoring function is disabled; and to control the first MOSFET and the third MOSFET to remain open and the second MOSFET to remain closed when the monitoring function is enabled.

5. A gate drive circuit for a press-fit IGBT, characterized in that: The gate drive circuit integrates the online monitoring circuit according to any one of claims 1 to 4; wherein the drain of the third MOSFET is connected to the output port of the gate drive circuit.

6. The gate driving circuit according to claim 5, wherein: It also includes a second control module for controlling the output signal switch of the gate drive circuit through a PWM signal; after a delay of 1 microsecond to 2 microseconds after the falling edge of a certain PWM signal, the monitoring function of the monitoring circuit is turned on; during the monitoring period, after the collector current of the crimped IGBT reaches a preset threshold, the virtual threshold voltage of the crimped IGBT is collected multiple times and the average is calculated, and the average is used as the virtual threshold voltage monitoring result; after a sudden change occurs in the collected value of the virtual threshold voltage of the crimped IGBT, the monitoring function of the monitoring circuit is turned off.

7. A power electronic power converter, characterized in that: Comprising the press-fit IGBT gate drive circuit as claimed in claim 5 or 6.

8. A method for calculating the junction temperature of a press-fit IGBT based on a virtual threshold voltage, characterized in that: include: A fitting relationship between the junction temperature and the virtual threshold voltage of the target press-fit IGBT under the current pressure is calibrated, wherein the virtual threshold voltage data during the calibration process is obtained by monitoring the press-fit IGBT virtual threshold voltage online monitoring circuit according to any one of claims 1 to 4; The virtual threshold voltage monitored in real time is substituted into the fitting equation to obtain the current junction temperature.

9. A system for calculating junction temperature of a press-fit IGBT based on virtual threshold voltage, characterized in that: comprising at least one processor and at least one memory; The at least one memory is for storing computer instructions; The at least one processor is configured to execute at least part of the computer instructions to implement the junction temperature calculation method according to claim 8.

10. The junction temperature calculation system according to claim 9, wherein: The system obtains junction temperature data during the calibration process by the following method, specifically: Dig a groove on the side of the emitter Mo sheet close to the surface of the IGBT chip; Use adhesive to fix the thermocouple in the groove gap of the emitter Mo sheet; The voltage signal of the thermocouple is transmitted to a digital thermometer to obtain the surface temperature of the press-fit IGBT emitter.

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