Modeling and Characterization of Frequency-Domain Thermal Impedance for IGBT Module Through Heat Flow Information

Frequency-domain modeling is a relatively new approach for thermal impedance description of power semiconductor devices, and it has shown promising advantages to analyze the multitimescale thermal dynamics of power semiconductor devices under complex mission profiles. However, parameters in the frequency-domain thermal model are still difficult to be accurately extracted, and sometimes the extraction process would be complicated and ambiguous depending on the construction of power devices and heat sink. This article proposes a new method to identify these key parameters of the frequency-domain thermal model for power semiconductors. The proposed approach utilizes the information of heat flowing out of device and only requires temperature responses of three different locations in the heat path of insulated-gate bipolar transistor (IGBT) module under a step power-loss. By the proposed approach, the critical frequencies in the frequency-domain thermal model of IGBT module can be extracted more easily and accurately. The effectiveness of the proposed method is also validated by simulations and experiments.