Study on the failure of IGBT bonding wire based on temperature gradient

As the core device of power electronic converter, IGBT has been widely used in the fields of new energy generation, smart grid and aerospace. The existing research shows that the failure caused by power module failure is as high as 31%. And the module failure caused by bonding wire fault accounts for about 70%. Therefore, it is very important to study the aging, failure mechanism and health assessment method of IGBT bonding wires for safe and reliable operation of converter. In this paper, the bonding wires of IGBT module is taken as the research object. According to the actual structure and using the finite element simulation software, a three-dimensional multi- physical field electro-thermal coupling model is established. The influence of the number and position of the bonding wires falling off on the electro-thermal characteristics of IGBT chip is studied,and the results show that the uneven distribution of the bonding wires will cause the fluctuation of the junction temperature of IGBT chip.what's more, the increase of the number of the dropped bonding wires is the main reason for the rise of the junction temperature. Based on this model, a more sensitive temperature gradient model of IGBT chip is established. It is found that the temperature gradient model can accurately monitor the number of bonding wires dropped. It provides a new idea for the condition monitoring of bonding wires in IGBT .