IGBT bonding wire fault monitoring method and device based on maximum driving current change rate

Abstract

The invention discloses an IGBT bonding wire fault monitoring method and device based on a maximum driving current change rate. The method comprises the following steps: constructing a driving current change rate model of an IGBT; determining the moment when the output signal of the IGBT reaches the maximum variable quantity, and determining a driving current change rate maximum value model of the IGBT at the moment so as to determine whether the maximum driving current change rate is related to the bonding wire fault of the IGBT; the driving current change rate of the IGBT in the actual to-be-detected circuit is calculated through the current sampling circuit, so that the maximum driving current change rate of the IGBT in the actual to-be-detected circuit is determined; and determining a bonding wire fault monitoring model output by the current sampling circuit according to the maximum driving current change rate of the IGBT in the actual circuit to be detected, so as to realize the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model. The IGBT bonding wire fault on-line monitoring device can realize IGBT bonding wire fault on-line monitoring, and is simple and easy to realize, low in cost, small in size and high in precision, and a detection mode is irrelevant to operation parameters of a main circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of bonding wire fault monitoring, and in particular to an IGBT bonding wire fault monitoring method and device based on a maximum drive current change rate. Background Art

[0002] Insulated-Gate Bipolar Transistors (IGBTs), a key power device in industrial applications, are widely used in power transmission, rail transit, electric vehicles, and renewable energy generation. Research indicates that power modules, such as IGBTs, are the weakest link in power electronics systems, constantly subject to alternating electrical and thermal stresses. Sudden load changes, grid disturbances, temperature fluctuations, and electromagnetic interference can all cause IGBTs to experience open-circuit and short-circuit failures, resulting in a failure rate exceeding 60%.

[0003] IGBT failure can be categorized as chip failure and package failure. Package failure is primarily due to the varying thermal expansion coefficients of the raw materials used in the device's various structural layers. The IGBT is constantly subjected to alternating thermal stresses during operation, leading to package aging issues such as bond wire failure, voids in the solder layer, and cracks. In severe cases, this can lead to package failure. Chip failure, on the other hand, is caused by overvoltage and overcurrent conditions. It's worth noting that prolonged fatigue operation of the IGBT causes package aging, shrinking its safe operating range and significantly increasing the risk of chip failure under normal operating conditions. Therefore, the aging status of the IGBT's package is a crucial indicator of its safe and reliable operation.

[0004] The aging state of the IGBT is manifested as package aging, mainly including bonding wire aging and solder layer aging. Under normal circumstances, when the IGBT is used in a system with small operating temperature fluctuations (≤80K), the main aging of the solder layer occurs, manifested as solder layer cracks and voids; however, when the IGBT is used in a system with large operating temperature fluctuations (≥100K), the main aging of the bond wire occurs, manifested as bond wire cracks and falling off. In addition, bond wire aging accounts for 70% of package aging. Therefore, in the early stages of IGBT bond wire aging, online monitoring methods can be used to detect it in time, which can effectively reduce the occurrence of IGBT failures. Therefore, monitoring bond wire aging failures is of great significance to improving the reliability of IGBTs and power electronic systems. Summary of the Invention

[0005] The present invention aims to at least partially address the technical problems in the related art. To this end, a first object of the present invention is to provide an IGBT bond wire fault monitoring method based on the maximum drive current change rate, which can realize online monitoring of IGBT bond wire faults.

[0006] A second object of the present invention is to provide an IGBT bonding wire fault monitoring device based on the maximum drive current change rate.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] A fourth object of the present invention is to provide a bonding wire fault monitoring device.

[0009] To achieve the above object, the present invention is implemented through the following technical solutions:

[0010] A method for monitoring IGBT bonding wire faults based on a maximum drive current change rate, comprising:

[0011] Construct an IGBT driving current change rate model;

[0012] Determining the moment when the output signal of the IGBT reaches a maximum change amount, and determining a maximum driving current change rate model of the IGBT at the moment; wherein the maximum driving current change rate model indicates that the maximum driving current change rate is related to whether a bonding wire failure occurs in the IGBT;

[0013] The driving current change rate of the IGBT in the actual circuit to be tested is calculated by a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested;

[0014] The bonding wire fault monitoring model obtained by the output of the current sampling circuit is determined according to the maximum driving current change rate of the IGBT in the actual circuit to be tested, so as to realize the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

[0015] In one possible implementation, the IGBT drive current change rate model is expressed as follows:

[0016]

[0017] Among them, i g (t) is the driving current of IGBT, is the driving current change rate of the IGBT, A0 is the falling slope of the IGBT output signal, L σ is the equivalent stray inductance of the IGBT drive circuit, A1, A2, S1, S2 are the first to fourth solution coefficients, t is the time, t x is the fall time of the IGBT output signal, e is a natural constant, ε(tt x ) is a step function with respect to time t;

[0018] Among them, the first to fourth solution coefficients are expressed as follows:

[0019]

[0020] Among them, V goff and V gon are the minimum and maximum values ​​of the IGBT driving voltage, R g is the equivalent driving resistance of the driving circuit, C ies is the equivalent input capacitance of the IGBT.

[0021] In one possible implementation, the maximum value of the IGBT drive current change rate when the IGBT output signal reaches the maximum change is expressed as follows:

[0022]

[0023] Among them, max means taking the maximum value, t0 means the moment when the output signal of the IGBT reaches the maximum change, It indicates the maximum value of the driving current change rate at the time t0 when the output signal of the IGBT reaches the maximum change.

[0024] In one possible implementation, a current sampling circuit based on a current transformer includes a current transformer, first to fifth resistors, first and second capacitors, first and second operational amplifiers, a diode, and a MOS transistor.

[0025] In which, the series branch of the first capacitor and the second resistor is respectively connected in parallel with the secondary winding of the current transformer and the first resistor, and the secondary winding of the current transformer is used to sense and detect the driving current of the IGBT in the actual circuit to be tested; the non-inverting end of the first operational amplifier is respectively connected to the first capacitor and the second resistor, the inverting end of the first operational amplifier is connected to the non-inverting end of the second operational amplifier, and the output end of the first operational amplifier is connected to the non-inverting end of the second operational amplifier through a diode and a third resistor; the second capacitor is connected in parallel between the drain and source of the MOS tube, and the drain of the MOS tube is connected to the non-inverting end of the second operational amplifier; the inverting end of the second operational amplifier is grounded through a fourth resistor and connected to its own output end through a fifth resistor, wherein the first operational amplifier, the diode, the third resistor and the second capacitor constitute a peak holding circuit; the output signal of the second operational amplifier is used to characterize the bonding wire fault monitoring model.

[0026] In one possible implementation, the driving current change rate of the IGBT in the actual circuit to be tested is represented by the following formula:

[0027]

[0028] Among them, v di(t) is the output voltage of the differential circuit, which is used to characterize the rate of change of the driving current of the IGBT in the actual circuit to be tested. N is the current transformer ratio. R1, R2 and C1 are the first resistor, second resistor and first capacitor in the current sampling circuit, wherein the first resistor, second resistor and first capacitor constitute the differential circuit.

[0029] In one possible implementation, the bond wire fault monitoring model is expressed as follows:

[0030]

[0031] Among them, V dim is the output signal of the second operational amplifier, R4 and R5 are the fourth and fifth resistors respectively, v di (t0) is the maximum driving current change rate of the IGBT in the actual circuit to be tested, V DF is the diode conduction voltage in the peak hold circuit.

[0032] To achieve the above-mentioned object, the second aspect of the present invention provides an IGBT bonding wire fault monitoring device based on the maximum drive current change rate, comprising:

[0033] The first building block is used to build a driving current change rate model of the IGBT;

[0034] The second construction module is configured to determine the moment when the output signal of the IGBT reaches a maximum change amount, and construct a maximum driving current change rate model of the IGBT at that moment; wherein the maximum driving current change rate model indicates that the maximum driving current change rate is related to whether a bonding wire failure occurs in the IGBT;

[0035] A solution module is used to calculate the driving current change rate of the IGBT in the actual circuit to be tested by a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested;

[0036] The third construction module is used to construct a bonding wire fault monitoring model according to the maximum driving current change rate of the IGBT in the actual circuit to be tested, so as to implement the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

[0037] To achieve the above objectives, the third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the above-mentioned IGBT bonding wire fault monitoring method based on the maximum drive current change rate is implemented.

[0038] To achieve the above-mentioned objectives, the fourth aspect of the present invention provides a bonding wire fault monitoring device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned IGBT bonding wire fault monitoring method based on the maximum drive current change rate is implemented.

[0039] The present invention has at least the following technical effects:

[0040] The present invention provides an IGBT bonding wire fault monitoring method and device based on the maximum drive current change rate. Specifically, the maximum drive current change rate of the IGBT is used as a health parameter to realize online monitoring of the IGBT bonding wire fault. Compared with the existing IGBT bonding wire fault monitoring method, the method is simple and easy to implement and can be applied to online monitoring. The corresponding device has the advantages of small size, low cost, high precision, and is not affected by the main circuit operating parameters. In addition, the present invention also provides a specific current sampling circuit based on a current transformer for calculating the IGBT drive current change rate, and a specific bonding wire fault monitoring model established based on the current sampling circuit, through which effective monitoring of the IGBT bonding wire fault can be realized.

[0041] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart of an IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to an embodiment of the present invention.

[0043] Figure 2 This is the waveform diagram of the IGBT shutdown process when there is no current load.

[0044] Figure 3 This is the equivalent circuit diagram of the IGBT drive circuit in the complex frequency domain.

[0045] Figure 4 The topology diagram of the single-phase inverter used in the experiment.

[0046] Figure 5 This is the current sampling circuit diagram for the maximum drive current change rate.

[0047] Figure 6 This is the working waveform of the current sampling circuit.

[0048] Figure 7 The figure shows the experimental results and theoretical comparison of the driving current and its differential.

[0049] Figure 8 This is the working waveform of the inverter in one power frequency cycle.

[0050] Figure 9 This is a detailed diagram of the working waveform of the IGBT under load current.

[0051] Figure 10 Detailed diagram of the working waveform of IGBT under no-load current condition.

[0052] Figure 11 The figure is a comparison chart of the experimental results of the driving current change rate under different conditions.

[0053] Figure 12 The figure below is a comparison of the maximum drive current change rate under different bond wire aging degrees.

[0054] Figure 13 A comparison chart of the sampling voltage at different bond wire aging levels.

[0055] Figure 14 Schematic diagram of the relationship between the bonding wire aging degree and the sampling voltage.

[0056] Figure 15 4 is a structural block diagram of an IGBT bonding wire fault monitoring device based on the maximum drive current change rate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present embodiment is described in detail below. Examples of the embodiment are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but are not to be construed as limiting the present invention.

[0058] The following describes the IGBT bonding wire fault monitoring method and device based on the maximum drive current change rate of this embodiment with reference to the accompanying drawings.

[0059] Figure 1 FIG. 1 is a flow chart of an IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0060] Step S101: constructing an IGBT driving current change rate model.

[0061] When the IGBT is turned off, the process is as follows: Figure 2 As shown, the falling process of the output signal of the driver chip IGBT is equivalent to a first-order linear function, and its expression V gd (t) can be expressed as:

[0062] V gd (t) = V gon +A0(tε(t)-(ttx )ε(tt x )) (1)

[0063] Among them, V gd (t) represents the output signal of the driver chip IGBT, V goff and V gon are the minimum and maximum values ​​of the IGBT drive voltage, A0 is the falling slope of the IGBT output signal, t is the time, ε(t) is the step function, and t x is the fall time of the IGBT output signal, ε(tt x ) is tt x The step function value at time ; where A0 is expressed as:

[0064]

[0065] The IGBT drive circuit is equivalent to a second-order circuit consisting of resistance, inductance and capacitance. Figure 3 As shown, where i g (s) is the complex frequency domain expression of the driving current, R g is the equivalent resistance of the drive circuit, including the internal resistance of the chip and the external drive resistance, L σ is the equivalent inductance in the drive circuit, C ies is the equivalent input capacitance of the IGBT, and its initial value is V Cies V gon Therefore, in the complex frequency domain, we can get g The expression of (s) is:

[0066]

[0067] Among them, s is the complex frequency domain variable, V gd (s) is V gd (t) The quantity after Laplace transformation can be expressed as:

[0068]

[0069] According to the time domain differential property of Laplace transform, the differential of the driving current can be expressed as

[0070]

[0071] Among them, i g (t) represents the time domain value of the IGBT driving current, Indicates a pair Find the Laplace transform of the function.

[0072] Therefore, the IGBT drive current change rate model is expressed as follows:

[0073]

[0074] in, is the driving current change rate of the IGBT, A1, A2, S1, S2 are the first to fourth solution coefficients, and e is a natural constant;

[0075] Among them, the first to fourth solution coefficients are expressed as follows:

[0076]

[0077] At the same time, the driving current i can be obtained by integrating the driving current change rate g The expression of (t) is:

[0078]

[0079] Among them, A3 and A4 are the fifth and sixth solution coefficients.

[0080] Step S102: determining the moment when the output signal of the IGBT reaches the maximum change amount, and determining the maximum driving current change rate model of the IGBT at the moment; wherein the maximum driving current change rate model indicates that the maximum driving current change rate is related to whether the IGBT has a bonding wire failure.

[0081] In one possible implementation, the output signal of the driver chip reaches its maximum change at time t0. Therefore, at this time, the rate of change of the drive current reaches its maximum value. Therefore, the maximum rate of change of the IGBT drive current at the moment when the output signal of the IGBT reaches its maximum change is expressed as follows:

[0082]

[0083] Among them, max means taking the maximum value, t0 means the moment when the output signal of the IGBT reaches the maximum change, It indicates the maximum value of the driving current change rate at the time t0 when the output signal of the IGBT reaches the maximum change.

[0084] It can be found that the maximum driving current change rate is proportional to the equivalent inductance L in the driving circuit. σ is directly related to the IGBT and has nothing to do with other operating parameters of the IGBT. When a bond wire failure occurs in the IGBT, L σ will increase, and the maximum drive current change rate will change accordingly.

[0085] It can be understood that the above steps S101 to S102 are used to determine whether a bonding wire failure occurs in the IGBT and is related to the maximum driving current change rate of the IGBT. Only after this is step S103 performed.

[0086] Step S103: obtaining the driving current change rate of the IGBT in the actual circuit to be tested by calculation using a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested.

[0087] In one possible implementation, the circuit used in the experimental verification of the present invention is a single-phase inverter circuit, and the IGBT to be tested is FF100R12KS4. The circuit schematic diagram is as follows: Figure 4 Select Figure 4 The IGBT4 in the circuit is used as the device to be tested, and the drive current is measured based on the current transformer to achieve sampling of the differential and maximum drive current change rate. The sampling circuit is as follows: Figure 5 As shown, the working principle waveform is as follows Figure 6 The current sampling circuit based on the current transformer includes a current transformer, a first resistor R1 to a fifth resistor R5, a first and a second capacitor C1-C2, a first and a second operational amplifier OP1 and OP2, a diode D1 and a MOS (metal oxide semiconductor field effect transistor) tube.

[0088] The series branch of the first capacitor C1 and the second resistor R2 is connected in parallel with the secondary winding of the current transformer and the first resistor R1 respectively. The secondary winding of the current transformer is used to sense and detect the IGBT in the actual circuit to be tested. Figure 4 The driving current of the IGBT4 in the middle is obtained; the non-inverting terminal of the first operational amplifier OP1 is respectively connected to the first capacitor C1 and the second resistor R2, the inverting terminal of the first operational amplifier OP1 is connected to the non-inverting terminal of the second operational amplifier OP2, and the output terminal of the first operational amplifier OP1 is connected to the non-inverting terminal of the second operational amplifier OP2 through the diode D1 and the third resistor R3; the second capacitor C2 is connected in parallel between the drain and source of the MOS tube, and the drain of the MOS tube is connected to the non-inverting terminal of the second operational amplifier OP2; the inverting terminal of the second operational amplifier OP2 is grounded through the fourth resistor R4, and is connected to its own output terminal through the fifth resistor R5, wherein the first operational amplifier OP1, the diode D1, the third resistor R3 and the second capacitor C2 constitute a peak holding circuit; the output signal of the second operational amplifier OP2 is used to characterize the bonding wire fault monitoring model.

[0089] Figure 5 In the circuit, R1, R2 and C1 form a differential circuit. The voltage of R2 can represent the current change rate of the driving circuit, and its voltage v can be obtained. di (t) is expressed as:

[0090]

[0091] Among them, v di(t) is the output voltage of the differential circuit, used to represent the rate of change of the drive current of the IGBT in the actual circuit to be measured, and N is the current transformer ratio.

[0092] It should be noted that the first operational amplifier OP1, the diode D1, the third resistor R3 and the second capacitor C2 in this embodiment form a peak holding circuit, which can obtain the maximum value of the rate of change of the drive current, V DF is the on-voltage of the diode in the peak holding circuit; Q1 is a reset switch of C2, and a control signal of Q1 is the same as a drive signal of the IGBT 4; R4, R5 and OP2 form an amplification circuit, and an output voltage of the amplification circuit is a sampling voltage, and an expression of the sampling voltage is a bonding wire fault monitoring model.

[0093] Step S104: determining the bonding wire fault monitoring model output by the current sampling circuit according to the maximum rate of change of the drive current of the IGBT in the actual circuit to be measured, so as to realize the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

[0094] In this embodiment, the bonding wire fault monitoring model is expressed as follows:

[0095]

[0096] wherein, V dim is the output signal of the second operational amplifier, v di (t0) is the maximum rate of change of the drive current of the IGBT in the actual circuit to be measured.

[0097] In this embodiment, the voltage value of V dim can be sampled to realize the online monitoring of the bonding wire fault of the IGBT.

[0098] Figure 7 is an experimental result and a theoretical comparison diagram of the drive current and the differential thereof, wherein V ee′ is a calculation result of the drive current differential model, V eE is a drive current differential waveform; i g′ is a calculation result of the drive current, i ge is an experimental measurement drive circuit waveform, which shows that the experimental result is consistent with the theoretical derivation, and the drive current differential model derived by the theory is accurate.

[0099] Figure 8 、 Figure 9 and Figure 10 are experimental results of the inverter, which show that the sampling circuit can accurately sample the maximum rate of change of the drive current in the inverter.

[0100] Figure 11The following is a comparison chart of the experimental results of the drive current change rate under different conditions. It can be seen from the figure that when the input voltage changes from 100 to 400V, the collector current changes from 0 to 40A, and the junction temperature changes from 30 to 120℃, the maximum drive current change rate of the IGBT remains unchanged.

[0101] Figure 12 and Figure 13 The driving current change rate and sampling circuit output voltage V under different bonding wire aging degrees dim Waveform diagram. It can be seen that the maximum driving current change rate V dim It decreases as the degree of bonding wire aging increases, indicating that the maximum driving current change rate can realize the monitoring of bonding wire aging.

[0102] Figure 14 Intuitively describes the degree of bonding wire aging and V dim The relationship between V dim The voltage value can reflect the aging degree of the IGBT bonding wire, which proves that the bonding wire fault monitoring model proposed in this embodiment is effective.

[0103] Furthermore, the present invention also provides an IGBT bonding wire fault monitoring device 100 based on the maximum driving current change rate.

[0104] Figure 15 FIG. 1 is a structural block diagram of an IGBT bonding wire fault monitoring device 100 based on the maximum driving current change rate according to an embodiment of the present invention. Figure 15 As shown, the IGBT bonding wire fault monitoring device 100 based on the maximum driving current change rate includes a first building module 10 , a second building module 20 , a solving module 30 , and a third building module 40 .

[0105] Among them, the first construction module 10 is used to construct a driving current change rate model of the IGBT; the second construction module 20 is used to determine the moment when the output signal of the IGBT reaches the maximum change amount, and construct a maximum driving current change rate model of the IGBT at the moment; wherein, the maximum driving current change rate model characterizes that the maximum driving current change rate is related to whether the IGBT has a bonding wire failure; the solution module 30 is used to calculate the driving current change rate of the IGBT in the actual circuit to be tested through a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested; the third construction module 40 is used to construct a bonding wire fault monitoring model based on the maximum driving current change rate of the IGBT in the actual circuit to be tested, so as to realize the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

[0106] It should be noted that the specific embodiments of the IGBT wire bonding fault monitoring device based on the maximum driving current change rate in the present embodiment can refer to the specific embodiments of the IGBT wire bonding fault monitoring method based on the maximum driving current change rate described above, and to avoid redundancy, details are not repeated here.

[0107] Further, the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the IGBT wire bonding fault monitoring method based on the maximum driving current change rate.

[0108] Further, the present application also provides a wire bonding fault monitoring device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to implement the IGBT wire bonding fault monitoring method based on the maximum driving current change rate.

[0109] The device embodiments described above are only schematic, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment. Those skilled in the art can understand and implement without creative labor.

[0110] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software plus necessary universal hardware platforms, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of software products, which can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and include a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0111] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for monitoring IGBT bonding wire faults based on maximum drive current change rate, characterized in that: include: Construct an IGBT driving current change rate model; Determining the moment when the output signal of the IGBT reaches a maximum change amount, and determining a maximum driving current change rate model of the IGBT at the moment; wherein the maximum driving current change rate model indicates that the maximum driving current change rate is related to whether a bonding wire failure occurs in the IGBT; The driving current change rate of the IGBT in the actual circuit to be tested is calculated by a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested; The bonding wire fault monitoring model obtained by the output of the current sampling circuit is determined according to the maximum driving current change rate of the IGBT in the actual circuit to be tested, so as to realize the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

2. The IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to claim 1, characterized in that: The IGBT drive current change rate model is expressed as follows: Among them, i g (t) is the driving current of IGBT, is the driving current change rate of the IGBT, A0 is the falling slope of the IGBT output signal, L σ is the equivalent stray inductance of the IGBT drive circuit, A1, A2, S1, S2 are the first to fourth solution coefficients, t is the time, t x is the fall time of the IGBT output signal, e is a natural constant, ε(tt x ) is a step function with respect to time t; Among them, the first to fourth solution coefficients are expressed as follows: Among them, V goff and V gon are the minimum and maximum values ​​of the IGBT driving voltage, R g is the equivalent driving resistance of the driving circuit, C ies is the equivalent input capacitance of the IGBT.

3. The IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to claim 2, characterized in that: The maximum value model of the IGBT drive current change rate when the IGBT output signal reaches the maximum change is expressed as follows: Among them, max means taking the maximum value, t0 means the moment when the output signal of the IGBT reaches the maximum change, It indicates the maximum value of the driving current change rate at the time t0 when the output signal of the IGBT reaches the maximum change.

4. The IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to claim 2, wherein: The current sampling circuit based on the current transformer includes a current transformer, first to fifth resistors, first and second capacitors, first and second operational amplifiers, a diode and a MOS tube; In which, the series branch of the first capacitor and the second resistor is respectively connected in parallel with the secondary winding of the current transformer and the first resistor, and the secondary winding of the current transformer is used to sense and detect the driving current of the IGBT in the actual circuit to be tested; the non-inverting end of the first operational amplifier is respectively connected to the first capacitor and the second resistor, the inverting end of the first operational amplifier is connected to the non-inverting end of the second operational amplifier, and the output end of the first operational amplifier is connected to the non-inverting end of the second operational amplifier through a diode and a third resistor; the second capacitor is connected in parallel between the drain and source of the MOS tube, and the drain of the MOS tube is connected to the non-inverting end of the second operational amplifier; the inverting end of the second operational amplifier is grounded through a fourth resistor and connected to its own output end through a fifth resistor, wherein the first operational amplifier, the diode, the third resistor and the second capacitor constitute a peak holding circuit; the output signal of the second operational amplifier is used to characterize the bonding wire fault monitoring model.

5. The IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to claim 4, characterized in that: The actual driving current change rate of the IGBT in the circuit to be tested is represented by the following formula: Among them, v di (t) is the output voltage of the differential circuit, which is used to characterize the rate of change of the driving current of the IGBT in the actual circuit to be tested. N is the current transformer ratio. R1, R2 and C1 are the first resistor, second resistor and first capacitor in the current sampling circuit, wherein the first resistor, second resistor and first capacitor constitute the differential circuit.

6. The IGBT bonding wire fault monitoring method based on the maximum drive current change rate according to claim 4 or 5, characterized in that: The bond wire fault monitoring model is expressed as follows: Among them, V dim is the output signal of the second operational amplifier, R4 and R5 are the fourth and fifth resistors respectively, v di (t0) is the maximum driving current change rate of the IGBT in the actual circuit to be tested, V DF is the diode conduction voltage in the peak hold circuit.

7. An IGBT bonding wire fault monitoring device based on maximum drive current change rate, characterized in that: include: The first building block is used to build a driving current change rate model of the IGBT; The second construction module is configured to determine the moment when the output signal of the IGBT reaches a maximum change amount, and construct a maximum driving current change rate model of the IGBT at that moment; wherein the maximum driving current change rate model indicates that the maximum driving current change rate is related to whether a bonding wire failure occurs in the IGBT; A solution module is used to calculate the driving current change rate of the IGBT in the actual circuit to be tested by a current sampling circuit based on a current transformer, so as to determine the maximum driving current change rate of the IGBT in the actual circuit to be tested; The third construction module is used to construct a bonding wire fault monitoring model according to the maximum driving current change rate of the IGBT in the actual circuit to be tested, so as to implement the bonding wire fault monitoring of the IGBT through the bonding wire fault monitoring model.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

9. A bonding wire fault monitoring device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

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