Temperature Rise and Identification Model of IGBT Chips Considering High Altitude Environment and Solder Layer Defects

For welded IGBT modules, there is no corresponding electro-thermal coupling model at high altitude, and there are few studies on chip failure caused by solder layer defects at high altitude. According to the coupling relationship between electric field and thermal field inside welded IGBT module, the electro-thermal coupling model of welded IGBT module at high altitude with different defect types and defect proportions in the solder layer of chip is established, and the effects of different altitudes, defects of voids, cracks and interface peeling in the solder layer on the maximum junction temperature of welded IGBT module are analyzed. The corresponding mechanism is explained, and the defect identification model of IGBT solder layer in high altitude area is proposed. The results show that different altitudes have different effects on chip temperature, and the chip temperature rises more obviously at high altitudes. When the defect proportion exceeds 5%, the impact of interface peeling on the chip temperature is much greater than that of crack defects and void defects. Meanwhile, the proposed defect identification model can accurately obtain the defect type and proportion of the solder layer of the chip and evaluate the health status of the solder layer. The research provides theoretical guidance for the health state detection of welded IGBT modules' solder layer in high altitude area and improving the operating stability of IGBT module.