Study on the Correction Method of Thermal Resistance of IGBT Module in Accelerated Aging Test Considering Influence of Glue of Thermocouple

Power cycling accelerated aging experiment is an important way to study the evolution process and failure mechanism of insulated gate bipolar transistor (IGBT) power modules under high power load impact. In the accelerated aging experiment, the thermal resistance as a sign of the fatigue fault of the IGBT module solder layer needs to be extracted online in real time, so as to achieve real-time monitoring of the aging degree of the aging process of the IGBT module. Measuring the case temperature with a thermocouple is an important step in the process of extracting the thermal resistance in each power cycle. However, the thermocouple is glued to the IGBT module, and the glue will fall off due to the constant impact and circulation of the temperature during the accelerated aging of the IGBT module. In this paper, in order to avoid the measuring error caused by thermocouple glue in the process of accelerated aging experiment, the correction method in the process of extracting IGBT module thermal resistance is proposed. In this paper, the influence of glue on the thermal resistance extraction is illustrated by finite element simulation and experiment, and the correction method is verified by the stability data in the experiment.