Inverter IGBT module bonding wire health state detection method based on differential mode interference and computer equipment

Abstract

The invention belongs to the technical field of inverter IGBT module detection, and particularly relates to an inverter IGBT module bonding wire health state detection method based on differential mode interference and computer equipment, and the method comprises the following steps: 1) obtaining a differential mode interference voltage peak value of an inverter under a set frequency band in an inversion process; 2) calculating the bonding wire equivalent impedance when the bonding wire falling number is a bonding wire falling number threshold value, and calculating the bonding wire falling number according to the pre-obtained relationship between the bonding wire equivalent impedance of the inverter IGBT module in different states in the action process and the differential mode interference voltage in the complex frequency domain; obtaining a differential mode interference voltage corresponding to the bonding wire falling-off number threshold value under a set frequency band, and determining a differential mode interference voltage threshold value according to the obtained differential mode interference voltage; and comparing the differential-mode interference voltage peak value with a differential-mode interference voltage threshold value, and if the differential-mode interference voltage peak value is greater than or equal to the differential-mode interference voltage threshold value, judging that the bonding wire falling number of the IGBT module of the inverter is greater than or equal to a bonding wire falling number threshold value.

Description

Technical Field

[0001] The present invention belongs to the technical field of inverter IGBT module detection, and in particular relates to an inverter IGBT module bonding wire health state detection method and computer equipment based on differential mode interference. Background Art

[0002] The power inverter IGBT module is an important module for realizing the inverter function. It is composed of multiple IGBT chips to form a full-bridge structure. In the IGBT package module, the chips and chips, and the chips and external electrical terminals are electrically connected through aluminum bonding wires. The long-term operation of the IGBT is subject to thermal stress caused by temperature cycles and harsh environments, which causes shear stress between the bonding wires, chips and solder layers with different thermal expansion coefficients. Under its continuous action, the bonding wires will deform or crack, and then fall off. As the degree of aging deepens, the module will eventually fail. Since the bonding wires are encapsulated inside the IGBT, its health status cannot be directly observed. Therefore, it is necessary to indirectly monitor the health status of the bonding wires (mainly the shedding of the bonding wires) by observing the changes in other electrical parameters. Traditional characteristic indicators of IGBT health status include gate-emitter frequency response, on-state resistance, on-state voltage drop, Miller platform, short-circuit current, module transconductance, etc. However, these health status monitoring based on characteristic indicators are limited to specific operating conditions in the laboratory. Outside of specific conditions, these indicators cannot accurately reflect the health status of the IGBT. In actual operating conditions, specific conditions are not easy to occur. Therefore, it is impossible to monitor the health status of the bonding wires through traditional characteristic indicators, especially to detect the detachment of the bonding wires of the IGBT module. Summary of the invention

[0003] The purpose of the present invention is to provide an inverter IGBT module bonding wire health status detection method and computer equipment based on differential mode interference, so as to solve the technical problem that the characteristic indicators of the traditional IGBT health status cannot accurately reflect the IGBT bonding wire detachment situation under actual operating conditions.

[0004] In order to solve the above technical problems, the present invention provides a method for detecting the health status of the bonding wires of an inverter IGBT module based on differential mode interference, comprising the following steps:

[0005] 1) Obtaining the peak value of the differential mode interference voltage of the inverter at a set frequency band during the inverter process;

[0006] 2) Calculate the bonding wire equivalent impedance when the number of bond wires that have fallen off is the bonding wire falling off threshold, and obtain the differential mode interference voltage corresponding to the bonding wire falling off threshold in the set frequency band according to the pre-obtained relationship between the bonding wire equivalent impedance and the differential mode interference voltage in different states of the inverter IGBT module during operation in the complex frequency domain, and then determine the differential mode interference voltage threshold according to the obtained differential mode interference voltage; compare the differential mode interference voltage peak value with the differential mode interference voltage threshold, and if the differential mode interference voltage peak value is greater than or equal to the differential mode interference voltage threshold, then determine that the number of bond wires that have fallen off of the inverter's IGBT module is greater than or equal to the bonding wire falling off threshold.

[0007] Further, it is characterized in that the threshold value of the number of bond wires falling off includes the threshold value of the number of bond wires falling off when the IGBT module is operating normally and the threshold value of the number of bond wires falling off when the IGBT module is faulty; the corresponding differential mode interference voltage threshold value includes the differential mode interference voltage threshold value when the IGBT module is operating normally and the differential mode interference voltage threshold value when the IGBT module is faulty; the threshold value of the number of bond wires falling off when the IGBT module is operating normally is less than the threshold value of the number of bond wires falling off when the IGBT module is faulty, and the differential mode interference voltage threshold value when the IGBT module is operating normally is less than the differential mode interference voltage threshold value when the IGBT module is faulty;

[0008] If the differential-mode interference voltage peak is greater than or equal to the differential-mode interference voltage threshold of IGBT module failure, the IGBT module is determined to be faulty; if the differential-mode interference voltage peak is less than the differential-mode interference voltage threshold of normal operation of the IGBT module, the IGBT module is determined to be normal operation; if the differential-mode interference voltage peak is greater than or equal to the differential-mode interference voltage threshold of normal operation of the IGBT module, and less than the differential-mode interference voltage threshold of IGBT module failure, the IGBT module is determined to be in a sub-healthy state.

[0009] Furthermore, the method further comprises the following steps:

[0010] 3) Calculate the equivalent impedance of the bonding wires with different numbers of bond wires falling off when the IGBT module is in a sub-healthy state, and obtain the differential mode interference voltage corresponding to the number of bond wires falling off in a set frequency band according to the relationship; compare the differential mode interference voltage peak value of the IGBT module in the sub-healthy state with the differential mode interference voltage corresponding to the number of bond wires falling off in the set frequency band to determine the number of bond wires falling off.

[0011] Furthermore, the relationship between the equivalent impedance of the bonding wire and the differential mode interference voltage in different states of the inverter IGBT module during operation in the complex frequency domain is obtained through the following process:

[0012] (1) Establish an equivalent circuit model of transient differential mode interference of the IGBT module of the inverter during operation;

[0013] (2) establishing an equivalent circuit model of the inverter, and performing frequency domain analysis to obtain a complex frequency domain relationship of the bonding wire equivalent impedance; the IGBT module in the equivalent circuit model of the inverter is simplified according to the transient differential mode interference equivalent circuit model;

[0014] (3) According to the topological structure of the IGBT module of the inverter, the equivalent circuit structure diagram of the inverter IGBT module in different states during the operation process is established, and based on the equivalent circuit structure diagram of the IGBT module in different operation states and the complex frequency domain relationship of the bonding wire equivalent impedance, the relationship between the bonding wire equivalent impedance and the differential mode interference voltage of the IGBT module in different operation states is obtained.

[0015] Furthermore, the step of determining the differential mode interference voltage threshold value according to the obtained differential mode interference voltage includes: multiplying the maximum value of the obtained differential mode interference voltage by a correction coefficient to obtain the differential mode interference voltage threshold value.

[0016] Furthermore, the frequency of the set frequency band is between 150KHz-600KHz.

[0017] Furthermore, the action process is a shut-down process.

[0018] The present invention is a pioneering invention, and its beneficial effects are as follows: the inverter IGBT module bonding wire health status detection method based on differential mode interference of the present invention proposes a new technical solution for detecting the bonding wire detachment of the inverter IGBT module by using the relationship between the differential mode interference voltage and the bonding wire equivalent impedance. Since the relationship does not depend on specific working conditions and always exists in the actual operation of the IGBT module, the inverter IGBT module bonding wire health status detection method based on differential mode interference of the present invention uses the relationship to calculate the differential mode interference voltage threshold corresponding to the bonding wire detachment number threshold when the bonding wire detachment number is the bonding wire detachment number threshold, and compares the differential mode interference voltage threshold with the measured value of the differential mode interference voltage to determine whether the bonding wire detachment number of the inverter IGBT module exceeds the bonding wire detachment number threshold. The detection does not depend on the specific working conditions during the test, and the IGBT module can be detected in real time during use, which has the technical effects of convenient and fast detection and no influence on the use of the IGBT module.

[0019] To solve the above technical problems, the present invention further provides a computer device, including a processor, which implements the steps of the inverter IGBT module bonding wire health status detection method based on differential mode interference as described in the present invention when executing a computer program.

[0020] The present invention is a pioneering invention, and its beneficial effects are as follows: the computer device of the present invention proposes a new technical solution for detecting the bond wire detachment of the inverter IGBT module by using the relationship between the differential mode interference voltage and the equivalent impedance of the bonding wire. Since the relationship does not depend on specific working conditions and always exists in the actual operation of the IGBT module, the inverter IGBT module bonding wire health state detection method based on differential mode interference of the present invention uses the relationship to calculate the differential mode interference voltage threshold corresponding to the bond wire detachment number threshold when the bond wire detachment number is the bond wire detachment number threshold, and compares the differential mode interference voltage threshold with the measured value of the differential mode interference voltage to determine whether the bond wire detachment number of the inverter IGBT module exceeds the bond wire detachment number threshold. The detection does not depend on the specific working conditions during the test, and the IGBT module can be detected in real time during use, which has the technical effect of convenient and fast detection and no influence on the use of the IGBT module. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of a method for detecting the healthy state of an inverter IGBT module bonding wire based on differential mode interference according to a method embodiment of the present invention;

[0022] Figure 2 is a voltage and current waveform diagram of the IGBT module shutdown process of the method embodiment of the present invention;

[0023] Figure 3 is a transient equivalent circuit model diagram of an IGBT module turn-off according to a method embodiment of the present invention;

[0024] Figure 4 EMI analysis topology diagram of a voltage-type three-phase full-bridge inverter according to an embodiment of the method of the present invention;

[0025] Figure 5 is an equivalent circuit diagram of an IGBT turn-off transient inverter EMI analysis of a method embodiment of the present invention;

[0026] Figure 6 It is a transient equivalent circuit structure diagram of the inverter action state switching of the method embodiment of the present invention;

[0027] Figure 7 is an equivalent circuit diagram of the inverter mode 1 of the method embodiment of the present invention;

[0028] Figure 8 is an electromagnetic interference path diagram of an inverter in actual working conditions of a method embodiment of the present invention;

[0029] Fig. 9 1 is a diagram of a health status assessment scheme for an inverter according to a method embodiment of the present invention. DETAILED DESCRIPTION

[0030] The inverter IGBT module bonding wire health status detection method and computer equipment based on differential mode interference of the present invention propose a new technical solution for detecting the bonding wire detachment of the inverter IGBT module by using the relationship between the differential mode interference voltage and the bonding wire equivalent impedance. Since the relationship does not depend on specific working conditions and always exists in the actual operation of the IGBT module, the inverter IGBT module bonding wire health status detection method based on differential mode interference of the present invention uses the relationship to calculate the differential mode interference voltage threshold corresponding to the bonding wire detachment number threshold when the bonding wire detachment number is the bonding wire detachment number threshold, and compares the differential mode interference voltage threshold with the measured value of the differential mode interference voltage to determine whether the bonding wire detachment number of the inverter IGBT module exceeds the bonding wire detachment number threshold. The detection does not depend on the specific working conditions during the test, and the IGBT module can be detected in real time during use, which has the technical effect of convenient and fast detection and no influence on the use of the IGBT module.

[0031] Method Example:

[0032] like Figure 1 As shown, the inverter IGBT module bonding wire health status detection method based on differential mode interference of the present invention comprises the following steps:

[0033] Step 1: Model the IGBT module equivalent circuit based on the IGBT operating mechanism.

[0034] First, according to the operating mechanism of IGBT, an equivalent circuit model of IGBT turn-off transient differential mode interference is established. The voltage and current waveforms of the IGBT module turn-off process are as follows: Figure 2As shown. In the figure, Vmiller is the Miller platform voltage, Ig is the gate current, and Ic is the collector current. At t0, the IGBT chip starts to shut down, the parasitic capacitance Cge starts to discharge, the gate-emitter voltage decreases, and the gate current increases; at t1, the Miller capacitance starts to discharge, and Vge remains constant. In the T1 stage, the Miller capacitance is discharged, and the gate-emitter voltage starts to decrease from the Miller platform voltage. During this process, the gate-emitter voltage is greater than the threshold voltage, so the collector current remains constant. In the T2 stage, the gate-emitter voltage is less than the threshold voltage, the IGBT transistor is turned off, the collector current drops rapidly, the return gate current decreases, and the current flowing through the IGBT disappears quickly. In the T3 stage, the PNP transistor is gradually turned off, and there is no reverse voltage in the IGBT chip. A large number of excess carriers left in the IGBT chip turn-on stage need to be recombined during the IGBT chip turn-off process. This process takes a relatively long time, causing the collector current Ic to slowly decrease and enter the tailing stage. The current tailing decline rate in the T3 stage is obviously lower than the collector current decline rate in the T2 stage. According to the differential mode interference voltage calculation formula, the greater the current change rate, the stronger the differential mode interference signal. The differential mode interference signal in the circuit is mainly generated by the collector current that decays rapidly during the T2 stage. The differential mode interference voltage is Figure 8 Equivalent resistance Z LINE If the equivalent resistance Z is not added in actual operation, LINE If the voltage is different, the differential mode interference voltage can be indirectly obtained by measuring the inverter loop current and making a difference.

[0035]

[0036] During the rapid decrease stage of the collector current, the IGBT chip operates in the active area. As the collector-emitter voltage increases, the channel of the IGBT part is pinched off, and the electron current and hole current are superimposed to form the collector current.

[0037]

[0038] Among them I D is the drain current of the IGBT, α pnp is the current gain of the PNP transistor. During the turn-on process, the drain current in the IGBT tube is as shown in the following formula.

[0039]

[0040] where μ is the carrier mobility, C OX is the oxide capacitance, W is the IGBT transistor channel width, L is the IGBT transistor channel length, V ge is the gate-emitter voltage of the IGBT chip, V th is the threshold voltage, so the collector current is as shown below.

[0041]

[0042] The current change rate during the stage when the collector current drops rapidly is shown in the following formula.

[0043]

[0044] Arranging the above formulas, we can get:

[0045]

[0046] Before the collector current drops rapidly, the gate parasitic capacitance has been discharged, so V ge and V th Not affected by temperature changes and dV ge / dt is also not affected by temperature changes during the shutdown process of the IGBT chip. The collector current that changes with time during this process is shown below:

[0047]

[0048] In the formula, due to the inductive load and continuous current, the load current I L Considered as a constant current source.

[0049] From the above formula, we can see that the IGBT chip behavior model in the rapid current drop stage can be equivalent to a time-varying current source with parasitic capacitance between the internal terminals. Considering the equivalent impedance Z of the bonding wire bondwires and the stray inductance L of the switching loop s , so the equivalent circuit of the IGBT module is as follows Figure 3 shown.

[0050] Step 2: According to the inverter topology, establish the inverter equivalent circuit model and perform frequency domain analysis.

[0051] According to the topology of the inverter, an equivalent circuit model is established for frequency domain analysis. In order to facilitate simulation analysis and verification, in this embodiment, an EMI analysis module is added to the differential mode interference loop of the inverter. Therefore, the inverter topology is as follows: Figure 4 shown.

[0052] The differential-mode interference voltage generated by the IGBT module during the shutdown process is much larger than the differential-mode interference voltage generated during the turn-on process. Therefore, this embodiment uses the differential-mode interference voltage generated by the IGBT shutdown process during the switching of different action states in the inverter working condition to establish an equivalent circuit model and perform frequency domain analysis, which has the beneficial effect of facilitating detection. As other implementation methods, the equivalent circuit model can also be established and frequency domain analyzed for the opening process of the IGBT module, and the differential-mode interference voltage of the IGBT module opening process can be used for detection. In order to facilitate modeling and analysis of different action states, the equivalent model of the inverter is divided into three modules, such as Figure 5 As shown in the figure, the IGBT switch loop equivalent circuit module is simplified according to the Norton theorem to simplify the IGBT module turn-off transient equivalent circuit model into the IGBT module equivalent to the internal parasitic parameters and the bonding wire impedance equivalent impedance parallel equivalent current source, and conduct complex frequency domain circuit analysis.

[0053]

[0054] Where Rg is the gate resistance, Zbondwires is the equivalent impedance of the bonding wire, I(s) is the frequency domain expression of the collector current that drops rapidly during the turn-off process, and Z eq It is the equivalent impedance of the two-terminal network after the current source is set to zero.

[0055] Step 3: Establish an equivalent circuit structure diagram of the inverter IGBT module in different states during operation. According to the equivalent circuit structure diagram of the IGBT module in different states, obtain the differential mode interference voltage in different states, and establish the functional relationship between the differential mode interference voltage and the equivalent impedance of the bonding wire.

[0056] Considering that the connection mode of the LINE differential mode voltage measurement module does not change during the transient process of the inverter switching between different operating states, Figure 6 The equivalent circuit of the topological structure of the IGBT switch circuit and the three-phase load during all action state switching processes is shown, where I(s) is the IGBT switch circuit module.

[0057] This embodiment takes the T0~T1 state switching process as an example. Figure 7 As shown, a functional relationship between the differential mode interference voltage and the bonding wire equivalent impedance is established.

[0058]

[0059] Z2=2jωL n

[0060] Z3=R c1 +jωL c1

[0061] Z4=R c2 +jωLc2

[0062]

[0063] Using Norton's theorem, the three-phase load and IGBT switching circuit are equivalent to the form of current source parallel impedance.

[0064]

[0065] I′ (s) =I (s)

[0066] Z′ eq It is the combined equivalent impedance of the load part and the IGBT switching loop in the inverter circuit.

[0067] according to Figure 7 As shown, combined with the above formula, we can get:

[0068]

[0069] Among them, Z1, Z2, Z3, Z4, Z dM 、V dM They are the series impedance of the resistor and capacitor in the LISN, the series impedance of the two LISN inductors, the line impedance of the connecting wire, the equivalent impedance of the direct-connected capacitor, R n The equivalent differential mode impedance and the resistance R in LISN N1 , R N2 The voltage on the differential mode interference voltage is defined as U dM . Resistance R N1 , R N2 The resistance value is equal to Rn.

[0070] According to the same method, V in the processes T1-T2, T2-T3, T3-T4, T4-T5 and T5-T6 can also be obtained. dM The equivalent impedance Z of the bonding wire in the six processes is obtained. bondwires The peak value of the differential mode interference voltage U dM The functional relationship in the complex frequency domain, namely U dM With Z bondwires Positive correlation.

[0071] When the number of bond wires falling off increases, it is equivalent to the conductor cross-sectional area becoming smaller and the resistance value increasing, that is, the bond wire impedance Z bondwires Take 7 bonding wires as an example. After one bonding wire falls off, the cross-sectional area of ​​the entire bonding wire becomes 6 / 7 of the original. Since the resistance of the conductor is inversely proportional to the cross-sectional area, after one bonding wire falls off, the equivalent impedance of the entire bonding wire becomes 7 / 6 of the original.

[0072] According to the above functional relationship, when the equivalent impedance of the bonding wire increases, the differential mode interference voltage peak value U dM Therefore, the peak value of the differential mode interference voltage U dM The change can clearly reflect the number of cracks in the bonding wires of the IGBT module.

[0073] Step 4: Obtain the peak value of the differential mode interference voltage of the inverter in the set frequency band during the inverter process.

[0074] Considering that in actual working conditions, the inverter cannot be equipped with a LINE electromagnetic interference measurement circuit, each power line contains common-mode and differential-mode interference components, such as Figure 8 As shown, noise separation is required. In the absence of LISN (Line Impedance Stabilization Network) and EMI (Electromagnetic Interference) analyzers, according to the differential-mode and common-mode interference transmission paths and characteristics, the current probe measurement winding method is changed to measure accurate differential-mode interference current. The winding method measurement equipment for measuring differential-mode interference current is a current probe and a spectrum analyzer. The test process does not require direct contact with the system under test to measure the differential-mode interference signal, and then monitors the aging degree of the IGBT module bonding wire under different operating states of the inverter, as shown in Table 1.

[0075] Table 1.U dM Table of relationship between IGBT bonding wire shedding degree

[0076]

[0077]

[0078] According to the measured differential mode interference signal, the peak value U of the differential mode interference voltage in the set frequency band during the inversion process is obtained. dM .

[0079] Step 5: Calculate the differential mode interference voltage threshold to determine whether the IGBT needs to be replaced.

[0080] Four bond wires are broken (the threshold number of bond wires falling off for IGBT module failure) as the IGBT limit operating condition, and the equivalent impedance of the bond wires of the inverter IGBT under this condition is calculated. The inverter IGBT module is analyzed in different states (T0-T1, T1-T2, T2-T3, T3-T4, T4-T5 and T5-T6) under the set frequency band during the rapid decay of the collector current under this condition. In this embodiment, the differential mode interference voltage of all cases when the bonding wire is broken is defined as The maximum value of As another implementation method, the state of the IGBT module may be determined first, and the corresponding differential mode interference voltage may be determined according to the state of the IGBT module. As After correction, the differential mode interference voltage threshold is obtained.

[0081] T is the number of bond wire breaks, where T=4.

[0082] According to the actual working conditions Correction is made to obtain the maximum differential mode interference voltage that may occur during normal operation under actual working conditions (differential mode interference voltage threshold for IGBT module failure)

[0083]

[0084] Where K re It is the correction factor, usually ranging from 1.05 to 1.1.

[0085] in accordance with Determine the health status of the inverter. When the number of bond wire breakages of the IGBT module exceeds the bond wire fall-off threshold, the inverter is not operating normally and the IGBT module needs to be replaced.

[0086] Step 6: Determine whether the bonding wire has not fallen off.

[0087] When monitored When the bonding wire of the inverter IGBT module is not detached, the equivalent impedance is calculated. According to the equivalent impedance at this time, the maximum value of the differential mode interference voltage under the set frequency band when the bonding wire of the IGBT module is not detached is calculated as According to the actual working conditions Correction is made to obtain the maximum differential mode interference voltage that may occur during normal operation under actual working conditions (differential mode interference voltage threshold for normal operation of IGBT module) like This indicates that the IGBT module is normal at this time.

[0088] In this embodiment, 4 wires are used as the threshold value of the number of bond wires that fall off when the IGBT module fails, and 0 wires are used as the threshold value of the number of bond wires that fall off when the IGBT module is operating normally. In actual use, these two thresholds can be set as needed, and the threshold value of the number of bond wires that fall off when the IGBT module is operating normally is less than the threshold value of the number of bond wires that fall off when the IGBT module is operating normally, and the corresponding differential mode interference voltage threshold value of the normal operation of the GBT module is less than the differential mode interference voltage threshold value of the IGBT module failure.

[0089] Step 7: When the bonding wires are detached but the number of detached bonding wires does not exceed the bonding wire detachment threshold, the number of detached bonding wires is determined.

[0090] When detected When the number of bond wires dropped is less than the bond wire drop threshold, it means that the bond wire has dropped, but the number of bond wires dropped does not exceed the bond wire drop threshold, and the IGBT module is in a sub-healthy state. At this time, the bond wire equivalent impedance corresponding to the number of bond wires dropped less than the bond wire drop threshold can be calculated respectively, and the maximum value of the corresponding differential mode interference voltage under the set frequency band can be calculated based on the equivalent impedance when the number of bond wires dropped is different. According to the actual working conditions Correction is made to obtain the maximum differential mode interference voltage that may occur during normal operation under actual working conditions. The peak value of the differential mode interference voltage U dM and Compare to determine the specific number of bond wires that have fallen off. Fig. 9 shown.

[0091] For example, if It can be determined that the number of bond wire detachments is 1.

[0092] For the convenience of explanation and understanding, the IGBT module bonding wire health status detection method for inverter IGBT differential mode interference in this embodiment also includes steps six and seven, which can not only determine whether the bonding wire detachment of the IGBT module exceeds the corresponding bonding wire detachment number threshold, but also determine whether the IGBT module is in a sub-healthy state, and determine the specific number of bonding wire detachments. In actual use, when it is not necessary to determine the specific number of bonding wire detachments, only steps one to six are used. Further, if it is not necessary to determine whether the IGBT module is in a sub-healthy state, then steps one to five are sufficient to determine whether the bonding wire detachment of the IGBT module exceeds the corresponding bonding wire detachment number threshold.

[0093] In this embodiment, the frequency band is set to be between 150kHz and 600kHz. Experiments have shown that the peak value of differential mode interference generated by the IGBT module in this frequency band is directly related to the aging degree of the bonding wire, and the influence of the junction temperature Tj can be ignored. This can improve the detection accuracy.

[0094] Through the above-mentioned method steps, the inverter IGBT module bonding wire health status detection method of the differential mode interference of the present invention does not rely on specific working conditions during the test, and can detect the IGBT module in real time during its use, which has the technical effect of convenient and fast detection and does not affect the use of the IGBT module.

[0095] Computer equipment example:

[0096] A computer device of the present invention includes a processor, wherein the processor implements the steps of the inverter IGBT module bonding wire health state detection method based on differential mode interference as described in the method embodiment when executing a computer program. The specific process, principle and beneficial effects of the method have been described in detail in the method embodiment, and will not be repeated in this embodiment.

[0097] The processor may be a microprocessor MCU, a programmable logic device FPGA or other processing device.

Claims

1. A method for detecting the health status of an inverter IGBT module bonding wire based on differential mode interference, characterized in that: The following steps are involved: 1) Obtaining the peak value of the differential mode interference voltage of the inverter at a set frequency band during the inverter process; 2) Calculate the bonding wire equivalent impedance when the number of bond wire detachments is the bonding wire detachment threshold, and obtain the differential mode interference voltage corresponding to the bonding wire detachment threshold in the set frequency band according to the pre-obtained relationship between the bonding wire equivalent impedance and the differential mode interference voltage in different states of the inverter IGBT module during operation in the complex frequency domain, and then determine the differential mode interference voltage threshold according to the obtained differential mode interference voltage; compare the differential mode interference voltage peak value with the differential mode interference voltage threshold, and if the differential mode interference voltage peak value is greater than or equal to the differential mode interference voltage threshold, then determine that the number of bond wire detachments of the inverter IGBT module is greater than or equal to the bonding wire detachment threshold.

2. The inverter IGBT module bonding wire health status detection method based on differential mode interference according to claim 1, characterized in that: The bonding wire falling-off number threshold includes the bonding wire falling-off number threshold for normal operation of the IGBT module and the bonding wire falling-off number threshold for a fault of the IGBT module; the corresponding differential mode interference voltage threshold includes the differential mode interference voltage threshold for normal operation of the IGBT module and the differential mode interference voltage threshold for a fault of the IGBT module; The threshold value of the number of bond wires falling off when the IGBT module is operating normally is smaller than the threshold value of the number of bond wires falling off when the IGBT module is faulty, and the threshold value of the differential mode interference voltage when the IGBT module is operating normally is smaller than the threshold value of the differential mode interference voltage when the IGBT module is faulty; If the peak value of the differential mode interference voltage is greater than or equal to the differential mode interference voltage threshold of the IGBT module failure, it is determined that the IGBT module is faulty; if the peak value of the differential mode interference voltage is less than the differential mode interference voltage threshold of the IGBT module normal operation, it is determined that the IGBT module is normal operation; If the differential mode interference voltage peak value is greater than or equal to the differential mode interference voltage threshold value of normal operation of the IGBT module and is less than the differential mode interference voltage threshold value of a fault of the IGBT module, it is determined that the IGBT module is in a sub-healthy state.

3. The inverter IGBT module bonding wire health status detection method based on differential mode interference according to claim 2, characterized in that: The following steps are also included: 3) Calculate the equivalent impedance of the bonding wires with different numbers of bond wires falling off when the IGBT module is in a sub-healthy state, and obtain the differential mode interference voltage corresponding to the number of bond wires falling off in a set frequency band according to the relationship; compare the differential mode interference voltage peak value of the IGBT module in the sub-healthy state with the differential mode interference voltage corresponding to the number of bond wires falling off in the set frequency band to determine the number of bond wires falling off.

4. The inverter IGBT module bonding wire health status detection method based on differential mode interference according to any one of claims 1 to 3, characterized in that: The relationship between the equivalent impedance of the bonding wire and the differential mode interference voltage in the complex frequency domain in different states during the operation of the inverter IGBT module is obtained through the following process: (1) Establish an equivalent circuit model of transient differential mode interference of the IGBT module of the inverter during operation; (2) establishing an equivalent circuit model of the inverter, and performing frequency domain analysis to obtain a complex frequency domain relationship of the bonding wire equivalent impedance; the IGBT module in the equivalent circuit model of the inverter is simplified according to the transient differential mode interference equivalent circuit model; (3) According to the topological structure of the IGBT module of the inverter, the equivalent circuit structure diagram of the inverter IGBT module in different states during the operation process is established, and based on the equivalent circuit structure diagram of the IGBT module in different operation states and the complex frequency domain relationship of the bonding wire equivalent impedance, the relationship between the bonding wire equivalent impedance and the differential mode interference voltage of the IGBT module in different operation states is obtained.

5. The inverter IGBT module bonding wire health status detection method based on differential mode interference according to any one of claims 1 to 3, characterized in that: The step of determining the differential mode interference voltage threshold value according to the obtained differential mode interference voltage includes: multiplying the maximum value of the obtained differential mode interference voltage by a correction coefficient to obtain the differential mode interference voltage threshold value.

6. The inverter IGBT module bonding wire health status detection method based on differential mode interference according to any one of claims 1 to 3, characterized in that: The frequency of the set frequency band is between 150KHz and 600KHz.

7. The method for detecting the health status of the bonding wire of the inverter IGBT module based on differential mode interference according to any one of claims 1 to 3, characterized in that: The action process is a shut-down process.

8. A computer device comprising a processor, characterized in that: The processor implements the steps of the inverter IGBT module bonding wire health status detection method based on differential mode interference as described in any one of claims 1 to 7 when executing the computer program.

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