Monitoring method of solder layer void damage of IGBT module based on transfer function

This paper proposes a method based on transfer function to monitor the solder layer void damage in IGBT modules. Firstly, the thermal resistance of each layer structure of IGBT module and the Cauer model is analyzed. Secondly, the process of obtaining the parameters of Cauer model by transfer function is analyzed. Finally, the thermal resistance of the IGBT module under different void fractions of the solder layer is measured by experiments, which obtains the relationship between the thermal resistance difference and the void fractions. In addition, this method is compared with the monitoring method by IEC standard, which verifies the accuracy and feasibility of this method.