阅读说明：本技术 Igbt模块键合线断裂在线监测装置、监测方法和应用 (IGBT module bonding wire breakage online monitoring device, monitoring method and application ) 是由 齐磊 张午宇 杜璐春 崔翔 张翔宇 于 2021-07-26 设计创作，主要内容包括：IGBT模块键合线断裂在线监测装置、监测方法和应用,测量半桥结构中,动作器件关断过程中互补器件的门极电压,通过和预先设置好的阈值比较得出IGBT模块键合线的断裂情况,包括如下步骤：步骤一：研制IGBT模块键合线断裂的在线监测装置,并与处于半桥电路中的IGBT模块相连；步骤二：建立IGBT模块健康状态时V-(GE)随负载电流变化的基准值；步骤三：建立键合线断裂后IGBT模块V-(GE)随负载电流变化的失效阈值；步骤四：启动IGBT模块在线监测装置,按照预定流程工作；步骤五：得出IGBT模块运行状态。(The IGBT module bonding wire breakage on-line monitoring device, the monitoring method and the application measure the gate voltage of a complementary device in the turn-off process of an action device in a half-bridge structure, and the breakage condition of the IGBT module bonding wire is obtained by comparing the gate voltage with a preset threshold value, and the method comprises the following steps: the method comprises the following steps: an online monitoring device for breakage of a bonding wire of an IGBT module is developed and connected with the IGBT module in a half-bridge circuit; step two: when establishing the health state of the IGBT module V GE A reference value that varies with the load current; step three: IGBT module after bonding wire breakage V GE A failure threshold that varies with load current; step four: starting the IGBT module online monitoring device, and working according to a preset flow; step five: and obtaining the running state of the IGBT module.)

The IGBT module bonding wire breakage online monitoring device comprises a load current measuring unit, a gate voltage measuring unit, a collector voltage zero-crossing detecting unit, a data processing unit and a health state early warning unit; it is characterized in that: the load current measuring unit and the gate pole voltage measuring unit are directly connected with the data processing unit, and the data processing unit is connected with the health state early warning unit; the collector voltage measuring unit is connected with the collector voltage zero-crossing detecting unit, and the collector voltage zero-crossing detecting unit is connected with the gate voltage measuring unit.

2. The IGBT module bonding wire breakage online monitoring device according to claim 1, characterized by: the voltage data obtained by the collector voltage measuring unit is processed by the collector voltage zero-crossing detecting unit, and the gate pole voltage measuring unit is started when a zero-crossing signal is detected.

3. The method for monitoring the breakage of the bonding wire of the IGBT module comprises the device for monitoring the breakage of the bonding wire of the IGBT module as claimed in any one of claims 1-2, and comprises the following steps:

the method comprises the following steps: connecting an IGBT module bonding wire breakage online monitoring device with an IGBT module in a half-bridge circuit;

step two: when establishing the health state of the IGBT moduleV _GEA reference value that varies with the load current;

step three: IGBT module after bonding wire breakageV _GEA failure threshold that varies with load current;

step four: starting the IGBT module online monitoring device, and working according to a preset flow;

step five: and obtaining the running state of the IGBT module.

4. The method for monitoring breakage of bonding wires of IGBT modules according to claim 3, characterized by: the step2 further comprises the following steps:

building a half-bridge double-pulse test circuit of the IGBT module; the IGBT module in a healthy state is used for carrying out IGBT module turn-off experiments under different load currents at 25 ℃, and collector currents in turn-off processes are recorded respectivelyI _LAnd gate voltage when collector voltage of complementary IGBT device passes through zeroV _{GE_baseline}Fitting the experimental data by the following formula to establishV _{GE_baseline}Current following loadI _LReference value of change:

in the formulak _{_baseline}、b _{_baseline}In a healthy stateV _{GE_baseline}Fitting parameters for the baseline values.

5. The method for monitoring breakage of bonding wires of IGBT modules according to claim 3, characterized by: the step3 further comprises the following steps:

building a half-bridge double-pulse test circuit of the IGBT module; cutting off all bonding wires at emitter terminals of one or two IGBT chips in the IGBT module respectively to simulate the breakage of the bonding wires of the IGBT module in actual operation, and carrying out an IGBT module turn-off experiment under different load currents at 25 ℃; recording the collector current of the turn-off process separatelyI _LAnd gate voltage when collector voltage of complementary IGBT device passes through zeroV _{GE_failure1}、V _{GE_failure2}Fitting the experimental data by the following formula to establishV _{GE_failure1}、V _{GE_failure2}Current following loadI _LVaried failure threshold:

in the formulak _{_failure1}、b _{_ failure1}When a bonding wire of an IGBT chip is brokenV _{GE_failure1}The fitting parameters of the failure threshold value are,k _{_failure2}、b _{_ failure2}when two IGBT chip bonding wires are brokenV _{GE_failure2}Fitting parameters for failure threshold.

6. The method for monitoring breakage of bonding wires of IGBT modules according to claim 1, characterized by: the step4 further comprises the following steps:

the predetermined process for breaking the bonding wire of the IGBT module is as follows:

step 1: initializing a monitoring device, resetting related monitoring quantity to zero, and starting a data processing unit;

step 2: starting a gate voltage measuring unit, monitoring whether the IGBT device is in a negative-pressure turn-off state, if the IGBT device is in the negative-pressure turn-off state, performing Step3, and if not, returning to Step 2;

step 3: closing the gate voltage measuring unit, starting the load current measuring unit, measuring the load currentI _L0 ；

Step 4: starting a collector voltage measuring unit and waiting for sampling;

step 5: starting a collector voltage zero-crossing monitoring unit, judging whether the collector voltage reaches zero, and if so, performing Step 6; otherwise, return to Step 4;

step 6: starting a gate voltage measuring unit to sample the current gate voltageV _{GE_monitor}Calculating health threshold and failure criterion, and judgingV _{GE_monitor}Whether or not it exceeds 1.3V _{GE_baseline}If yes, Step7 is carried out; otherwise, return to Step 4;

step 7: starting a health state early warning unit, and sending an alarm signal by a monitoring system to prompt that the fracture condition of a bonding wire exceeds a threshold value;

step 8: the monitoring system is reset.

7. The method for monitoring breakage of bonding wires of IGBT modules according to claim 1, characterized by: the step5 further comprises the following steps:

according to the gate voltage measured by the monitoring device in the step4V _{GE_monitor}Load currentI _L0Health state established in step2 and step3, and breakage of bonding wireV _GEAlong with the change relation of the load current, the health state of the IGBT module can be obtained through the data processing unit in the step1, and the criterion is as follows:

if it isV _{GE_monitor}<1.3 V _{GE_baseline} (I _L0) If the IGBT module is in a healthy state, judging whether the IGBT module is in a healthy state;

if 1.3 V _{GE_baseline} (I _L0)<V _{GE_monitor}<1.3 V _{GE_failure1}(I _L0) If the bonding wire of the emitter of one IGBT chip of the IGBT module is completely broken;

if 1.3 V _{GE_failure1}(I _L0) <V _{GE_monitor}<1.3 V _{GE_failure2}(I _L0) If the bonding wires of the emitter electrodes of the two IGBT chips of the IGBT module are all broken;

if it isV _{GE_monitor}>1.3 V _{GE_failure2}(I _L0) And all the bonding wires of the emitter of three or more IGBT chips of the IGBT module are broken.

8. The method for monitoring breakage of bonding wires of IGBT modules according to any one of claims 3 to 7 is applied to monitoring of multi-chip bonded-type Si MOSEFT modules or SiC MOSEFT modules.

Technical Field

The invention belongs to the technical measurement field of semiconductor devices, and particularly relates to a device, a method and application suitable for monitoring breakage of a bonding wire of an IGBT module.

Background

Power electronic converters are widely used in the industries of electric vehicles, wind power generation, direct current transmission, and the like. In the long-term operation process of the power electronic converter, the elements with performance degradation are identified before faults occur, the main purpose of state monitoring is achieved, and state monitoring on power electronic devices is an effective means for improving the reliability of the converter. Insulated Gate Bipolar Transistors (IGBTs) have found wide application due to their combination with the high switching speed of metal-oxide field effect transistors and the low turn-on loss of bipolar junction transistors. In the case of high-voltage and high-power electronic converters, such as wind power converters, traction converters, high-voltage direct-current power transmission, in order to improve the current capacity, multi-chip parallel IGBT modules are generally used, which are formed by connecting a plurality of IGBT or diode chips in parallel. The breakage of the bonding wire is a main failure mode of the IGBT module, and for the IGBT module with multiple parallel chips, the module failure cannot be caused due to the redundancy of the number of the chips. Therefore, chip failure caused by bond wire breakage becomes a precursor failure characteristic of multi-chip parallel IGBT module state monitoring.

Much research has been carried out on the monitoring of the breaking state of the bonding wire of the IGBT module, and the monitoring quantity signal can be divided into electric quantity and non-electric quantity. Non-electrical quantity monitoring methods include thermal pulse eddy current imaging, vibration displacement measurement and the like, and special measuring devices are needed to be unsuitable for online monitoring application. The broken bonding wire of the IGBT module can change loop resistance, stray inductance, capacitance distribution and the like, the essence of utilizing the electric quantity monitoring is the identification of circuit parameters, namely the change of characteristic electric quantity reflects the circuit parameter change caused by the broken bonding wire, and the larger the excitation source of the electric quantity is, the higher the identification precision is correspondingly.

The prior art, such as the chinese patent application, the application numbers thereof: CN2019104842800, publication No.: CN 110221189A discloses a method for monitoring the online state of a bonding wire of an IGBT module, which comprises the following steps: the method comprises the following steps: building a full-bridge inverter circuit and a VCE online measuring circuit, connecting two input ends of the VCE online measuring circuit to a collector and an emitter of an IGBT power module of the full-bridge inverter circuit, and realizing the connection of the full-bridge inverter circuit and the VCE online measuring circuit; step two: establishing a three-dimensional data model of the healthy IGBT; step three: establishing an IGBT three-dimensional data model with a broken bonding wire; step four: optimizing a least square support vector machine by adopting a genetic algorithm; step five: and performing state evaluation on the three-dimensional data model obtained in the second step and the third step by using the optimized least square support vector machine.

Chinese patent application, application number: CN201910825141x, publication No.: CN 110632490A discloses a device and a method for monitoring the state of an IGBT module, where the device includes an IGBT module, a gate turn-on voltage overshoot monitoring module, a driving circuit, a bonding wire state judgment module, and a signal acquisition module, and obtains the situation of the breaking of a bonding wire by comparing the monitored actual gate turn-on voltage overshoot with a preset reference gate turn-on voltage overshoot threshold.

Chinese patent application, application number: CN2020102863307, publication No.: CN 111398766A discloses an IGBT module health state on-line monitoring method and system, wherein an abnormal IGBT module is determined according to the current value of a collector electrode of each IGBT module in parallel connection of the IGBT modules; extracting the collector current value of each abnormal IGBT module, and comparing the collector current value with the maximum value in the measured values of the collector currents of the normal IGBT modules to obtain the current imbalance rate of each abnormal IGBT module; determining the abnormal type of the IGBT module according to the shell temperature of each IGBT module in the parallel IGBT modules; and for any abnormal IGBT module, bringing the current imbalance rate and the shell temperature of the abnormal IGBT module into a parallel IGBT health state detection model, and determining whether the abnormal IGBT module fails according to the abnormal type of the abnormal IGBT module.

However, the method disclosed in the above document cannot utilize the collector voltage as an excitation source for circuit parameter identification, so that the monitoring relative variation after the bonding wire of the IGBT module is broken is small; in addition, the monitoring amount of the monitoring method in the literature is easy to interfere due to a small excitation source, and the possibility of false alarm is high. The main defects of the existing method are that the relative change of the broken bonding wire is small, the monitoring is easy to be interfered, and the false alarm probability is high.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides the following technical scheme to overcome the defects in the background technology:

the IGBT module bonding wire breakage online monitoring device comprises a load current measuring unit, a gate voltage measuring unit, a collector voltage zero-crossing detecting unit, a data processing unit and a health state early warning unit; it is characterized in that: the load current measuring unit and the gate pole voltage measuring unit are directly connected with the data processing unit, and the data processing unit is connected with the health state early warning unit; the collector voltage measuring unit is connected with the collector voltage zero-crossing detecting unit, and the collector voltage zero-crossing detecting unit is connected with the gate voltage measuring unit.

The invention also discloses a method for monitoring breakage of the bonding wire of the IGBT module, which is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: connecting an IGBT module bonding wire breakage online monitoring device with an IGBT module in a half-bridge circuit;

step two: when establishing the health state of the IGBT moduleV _GEA reference value that varies with the load current;

step three: IGBT module after bonding wire breakageV _GEA failure threshold that varies with load current;

step four: starting the IGBT module online monitoring device, and working according to a preset flow;

step five: and obtaining the running state of the IGBT module.

The invention also discloses a method for monitoring the breakage of the bonding wire of the IGBT module, which is applied to monitoring a multi-chip-connection welding type Si MOSEFT module or a SiC MOSEFT module.

Advantageous effects

The invention combines the advantages of the slave gate circuit and the power circuit, the collector voltage of the power circuit is used as a circuit parameter identification source, and the relative variation is extremely high and is not easy to be interfered. The method is generally suitable for on-line monitoring of the power electronic converter with the half-bridge structure and off-line monitoring of the single IGBT module.

Drawings

FIG. 1 is a schematic diagram of the structure and connection of an IGBT module bonding wire breakage online monitoring device.

FIG. 2a and FIG. 2b are the internal structure and equivalent circuit of multi-chip parallel IGBT module used in the embodiment of the invention

Fig. 3a and 3b are voltage and current waveforms of the double pulse test circuit and the QT turn-off process according to the present invention, respectively.

FIG. 4(a) shows the equivalent circuit of the state of health module during the period t2-t3, and FIG. 4(b) shows the branch Q_B2Equivalent circuit in healthy state, branch Q of FIG. 4(c)_B2And (5) equivalent circuit after the bonding wire is broken.

Fig. 5 (a) is a structural part of a double-pulse experimental platform IGBT module established by the present invention, and fig. 5 (b) is an overall structure of the double-pulse experimental platform.

Fig. 6 is a schematic diagram of the method for monitoring breakage of the bonding wire of the IGBT module according to the present invention.

Fig. 7 is a predetermined flow chart of the IGBT module bonding wire monitoring device according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The IGBT module bonding wire breakage online monitoring device comprises a load current measuring unit, a gate voltage measuring unit, a collector voltage zero-crossing detecting unit, a data processing unit and a health state early warning unit; it is characterized in that: the load current measuring unit and the gate pole voltage measuring unit are directly connected with the data processing unit, and the data processing unit is connected with the health state early warning unit; the collector voltage measuring unit is connected with the collector voltage zero-crossing detecting unit, and the collector voltage zero-crossing detecting unit is connected with the gate voltage measuring unit. The voltage data obtained by the collector voltage measuring unit is processed by the collector voltage zero-crossing detecting unit, and the gate pole voltage measuring unit is started when a zero-crossing signal is detected.

A flow chart of a monitoring method suitable for IGBT module bonding wire breakage is shown in figure 7, and the flow chart utilizes a gate voltage at a collector voltage zero-crossing momentV _GEThe flow chart for monitoring the breakage of the bonding wire comprises the following specific steps:

the method comprises the following steps: connecting an IGBT module bonding wire breakage online monitoring device with an IGBT module in a half-bridge circuit;

step two: when establishing the health state of the IGBT moduleV _GEA reference value that varies with the load current;

step three: IGBT module after bonding wire breakageV _GEA failure threshold that varies with load current;

step four: starting the IGBT module online monitoring device, and working according to a preset flow;

step five: and obtaining the running state of the IGBT module.

Example 1

The method comprises the following steps: connecting an IGBT module bonding wire breakage online monitoring device with an IGBT module in a half-bridge circuit;

the IGBT module bonding wire breakage online monitoring device comprises a load current measuring unit, a collector voltage zero-crossing detecting unit, a gate voltage measuring unit, a data processing unit and a health state early warning unit, wherein all the units are connected in a mode and are connected with an IGBT module as shown in figure 1.

The load current measuring unit is used for measuring the load current and transmitting the measured data to the data processing unit;

the collector voltage measuring unit is connected with the collector voltage zero-crossing detecting unit, and the specific realization function is that voltage data measured by the collector voltage measuring unit is transmitted to the collector voltage zero-crossing detecting unit, and the gate voltage measuring unit is started when a zero-crossing signal is detected through the processing of the collector voltage zero-crossing detecting unit. The data processing unit is used for storing the measurement data, judging whether the device is in a negative pressure turn-off state or not, calculating a health state reference value and a failure threshold value at the moment according to the load current data, judging the failure condition and further starting the health state early warning unit.

Step two: when establishing the health state of the IGBT moduleV _GEA reference value that varies with the load current; the specific process is as follows:

the analysis is carried out by taking a commercial 1200V/450A IGBT module as an example, and the internal structure of the IGBT module and an equivalent circuit thereof are shown in FIG. 2. A single IGBT device comprises three IGBT chips and is stored in respective parallel branches, and is characterized in that an emitter of each IGBT chip and an anode of each diode are connected with a copper substrate through bonding wires respectively.

A half-bridge double-pulse test circuit of an IGBT module is built, as shown in fig. 3(a), an upper tube IGBT device is in a normal turn-off state, a lower tube IGBT device is always in a negative pressure turn-off state, load inductors are connected to two ends of the lower tube IGBT device in parallel, and a monitoring device is connected to two ends of the lower tube IGBT device in parallel. FIG. 3(b) is a schematic diagram showing voltage and current waveforms in the turn-off process of the IGBT device, and the turn-off process of the upper tube IGBT device is as followst ₁-t ₆Shown in stages, t₂-t₅Collector voltage of IGBT device under process tubev _CEBVariation of cross-talk voltage at gatev _GEB. Shown by solid linev _GEBGate voltage waveform for IGBT module health, shown by dotted linev _GEBFor gate voltage waveform after bond wire breakage, the invention measurest ₄Temporal gate voltageV _GEAnd the breakage of the bonding wire of the IGBT module is monitored.

1. First, the theory analysis is used to illustrateV _GEEffectiveness of monitoring breakage of bonding wires of the IGBT module:

in FIG. 3(b)t ₂-t ₃Shutdown procedure, equivalent circuit at this stage as shown in FIG. 4(a), upper transistor Q_TGate voltagev _GETClamped on a Miller platform, Miller capacitorC _GCTDischarge, Q_TCollector-emitter voltagev _CETGradually rising, Q_TCollector-emitter voltagev _CEBVoltage ofSynchronous falling, tube down diode D_BBiased non-conductive by negative pressure. Q_TCollector currenti _CKeeping the voltage constant, the parasitic inductance voltage drop of the power loop is 0, and d is providedv _CEB/dt=-dv _CET/dt. Lower tube Q_BGate-collector capacitanceC _GCBDischarge of electric currenti _GCBFlows through the driving resistorR _GB(on)Voltage drop is generated and is superposed on the gate-level driving power supply voltage of the lower tubeV _GBTo makev _GEBA transient negative voltage overshoot is generated. In the process, load current flows through the reactor and does not flow through the lower tube IGBT device.

Taking the IGBT QB2 branch as an example, the capacitance current distribution before the IGBT chip fails is as shown in fig. 4(b),C _GCB2current of capacitancei _GCB2By gate currenti _G2AndC _GEB2composition of discharge current, gate voltage if neglecting the effect of stray inductance in the loopv _GEBSatisfies the following conditions:

time in the formulaAt this stage the collector voltagev _CEBThe size of the composite material is larger,C _GCB2approximate source-drain depletion layer capacitance, the value of which isC _GCB2Relatively small.t ₂-t ₃Phasesv _GEBContinuously decrease, definet ₃Time of day, i.e. collector voltage zero crossing time, gate voltagev _GEComprises the following steps:

if IGBT Q_B2Failure of all bonding wires to cause gate-emitter capacitanceC _GEB2Disconnected from the emitter loop, as shown in FIG. 4(c), and the capacitorElectric currenti _GCBThe distribution of the water content is changed,i _GCB2flowing only through the drive resistor, the time constant decreases and at the same time the gate voltagev _GEBIs reduced compared with the situation before the failure,t ₃time of dayv _GEAnd is reduced accordingly. It can be seen thatt ₄Temporal gate voltageV _GEThe breaking of the bonding wire of the IGBT module can be effectively reflected.

2. When establishing the health state of the IGBT moduleV _GEReference value varied with load current:

by using an experimental platform, as shown in fig. 5. Load inductanceL _sConnected in parallel at two ends of the lower bridge device and the upper bridge deviceQ _TIn a normal on-off state; lower bridge deviceQ _BIs always in an off state and is in a device on the upper bridgeQ _TWhen turned off, the diode D_BProviding a freewheeling path for the load current. The upper bridge module and the lower bridge module are powered by an isolation power supply for the driving circuit. The experimental platform parameters are shown in the table. Varying load currentI _LAnd (5) carrying out double-pulse experiments for 50A, 75A and 100A, recording the gate voltage value at the time of t4, and obtaining the health state of the IGBT module in the step twoV _GEThe reference value changing with the load current is as follows:

step three: IGBT module after bonding wire breakageV _GEFailure threshold as a function of load current:

by using an experimental platform, as shown in fig. 5. In the example, an IGBT module is formed by cutting off an IGBT chip after an emitterV _GEThe failure threshold value changing along with the load current is taken as an example to explain the implementation process, and the method for establishing the failure threshold value after cutting off the emitters of the two IGBT chips only needs to repeat the process.

Cutting off the IGBT die shown in FIG. 1And the QB1 chip emitter bonding wire simulates the breaking failure of the bonding wire. Varying load currentI _LAnd (3) carrying out double-pulse experiments for 50A, 75A and 100A, and recording the gate voltage value at the time t4 to obtain the IGBT module after the bonding wire is broken in the step threeV _GEThe failure threshold, which varies with load current, is:

at a load current of 100A, a healthy stateV _GEis-10.82V, after the bond wire is brokenV _GEIt was-15.48V, and the relative change was 43.07%. The variation is obvious, and the experimental result verifies the effectiveness of the method.

Step four: starting the IGBT module on-line monitoring device, and working according to a preset flow:

the predetermined process for breaking the bonding wire of the IGBT module is as follows:

step 1: initializing a monitoring device, resetting related monitoring quantity to zero, and starting a data processing unit;

step 2: starting a gate voltage measuring unit, monitoring whether the IGBT device is in a negative-pressure turn-off state, if the IGBT device is in the negative-pressure turn-off state, performing Step3, and if not, returning to Step 2;

step 3: closing the gate voltage measuring unit, starting the load current measuring unit, measuring the load currentI _L0

Step 4: starting a collector voltage measuring unit and waiting for sampling;

step 5: starting a collector voltage zero-crossing monitoring unit, judging whether the collector voltage reaches zero, and if so, performing Step 6; otherwise, return to Step 4;

step 6: starting a gate voltage measuring unit to sample the current gate voltageV _{GE_monitor}Calculating health threshold and failure criterion, and judgingV _{GE_monitor}Whether or not it exceeds 1.3V _{GE_baseline}If yes, Step7 is carried out; otherwise, return to Step 4;

step 7: and starting the health state early warning unit, and sending an alarm signal by the monitoring system to prompt that the fracture condition of the bonding wire exceeds a threshold value.

Step 8: the monitoring system is reset.

Step five: and obtaining the running state of the IGBT module.

According to the gate voltage measured by the monitoring device in the step4V _{GE_monitor}Load currentI _L0Health state established in step2 and step3, and breakage of bonding wireV _GEAlong with the change relation of the load current, the health state of the IGBT module can be obtained through the data processing unit in the step1, and the criterion is as follows:

if it isV _{GE_monitor}<1.3 V _{GE_baseline}(I _L0) If the IGBT module is in a healthy state, judging whether the IGBT module is in a healthy state;

if 1.3 V _{GE_baseline}(I _L0)<V _{GE_monitor}<1.3 V _{GE_failure1}(I _L0) If the bonding wire of the emitter of one IGBT chip of the IGBT module is completely broken;

if 1.3 V _{GE_failure1}(I _L0) <V _{GE_monitor}<1.3 V _{GE_failure2}(I _L0) If the bonding wires of the emitter electrodes of the two IGBT chips of the IGBT module are all broken;

if it isV _{GE_monitor}>1.3 V _{GE_failure2}(I _L0) And all the bonding wires of the emitter of three or more IGBT chips of the IGBT module are broken.

The technical scheme of the invention has the following advantages:

(1) the method can realize the chip failure caused by the breakage of the bonding wire of the multi-chip parallel welding type IGBT module; the method is also suitable for chip failure caused by breakage of bonding wires of multi-chip parallel welding type Si MOSEFT modules, SiC MOSEFT modules and the like.

(2) The monitoring method is suitable for on-line monitoring application of a multi-chip parallel power module in a power electronic converter with a half-bridge structure and off-line monitoring application of a single multi-chip parallel power module;

(3) when the half-bridge structure action device is turned off, the gate voltage at the zero-crossing moment of the collector voltage of the complementary device is used as the monitoring quantity.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, although the present invention is described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art; modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.