Improved IGBT Dynamic Model and Electro-Thermal-Mechanical Multi-Field Coupling Failure Analysis

Failure of insulated gate bipolar transistors (IGBTs) can make a serious impact on the entire rectification or inverter system. IGBTs are used in different practical applications, causing a large difference in the form of failure of its solder layer. Therefore, it is necessary to study the aging failure law of IGBT solder layer. Firstly, the improved IGBT dynamic model is used to build a three-phase rectifier circuit and correct its circuit power consumption error. Then constructing three-dimensional finite element model of IGBT and analyzing its chip temperature and solder layer stress distribution under electro-thermal-force multiphysics coupling. Finally, the randomly generated solder layer defects are used to investigate the effects of voids, cracks, etc. on solder layer failure, and the aging failure mechanism of the solder layer is obtained. The simulation results show that after the solder layer defect area ratio is higher than 15%, solder layer voids, cracks and shedding have a significant effect on chip junction temperature and solder layer stress. Among them, shedding and cracks have a greater influence on the stress of the solder layer.