Research On Fault Characteristic Analysis And Condition Monitoring Technology Of IGBT Bonding Wire Lift-off

The insulated gate bipolar transistor(IGBT)power module is a widely used power electronic device.In the related equipment such as photovoltaic inverter,wind energy converter,energy storage inverter and flexible DC commutationValves plays a very important role.When the IGBT module occur failure,it is likely to lead to its equipment and even the entire system's paralysis,resulting in serious harm and great losses,so to ensure the reliability of IGBT operation,special attention is needed to pay to the problem,While the bonding wire lift off is one of the problems that cause IGBT reliability to be reduced and that is urgently needed.How to monitor the working state of IGBT bonding wire and analyze the failure characteristics of the module with its external measurable state parameters will be the focus of this paper.In this paper,the failure state analysis of the IGBT module is carried out,and the fault state of the IGBT module is evaluated and predicted by analyzing the selected end state parameters.The main work of this paper has the following aspects:(1)The main factors influencing the reliability operation of IGBT module are summarized,and the failure type and failure mechanism are analyzed.The fault characteristics of IGBT module bonding wire are studied emphatically according to the package structure,the internal structure,and the working principle.The influence of the bonding wire lift-off on the on-resistance,the turn-off time,gate threshold voltage and gate voltage Miller platform of the module is analyzed theoretically,which provides a theoretical basis for the subsequent fault feature analysis.(2)Based on the thermal stress analysis method,the temperature distribution,thermal stress and shear stress of the IGBT module during the normal operation are analyzed.It reveals that the place where the IGBT bonding wire temperature is highest is not the place where the thermal stress is greatest,and the edge of the bonding wire's thermal stress is the largest and more prone to bonding wire lift-off failure.(3)The experimental circuit is designed and built,and the on-state resistance,turn-off time,gate threshold voltage and gate voltage Miller platform characteristic parameters of the IGBT module are obtained by experiment.By comparing and analyzing the variation of each parameter,the correctness of the analysis of the external characteristic parameters is verified by the simulation,and the relationship between the change characteristics of the selected characteristic parameters and the degree of the bonding wire failure is obtained,that is,the open and close time of the module and the flat platform of the gate voltage decrease with the increasing degree of shedding of the bonding wire,while the on-state equivalent resistance and the gate threshold voltage show an increasing trend.