Thermal Network of Double-sided Cooling Power Module Based on Cauer Model

As the volume of power modules decreases and power density increases, the problem of efficient heat dissipation of high-power modules needs to be solved urgently. However, existing power module analytical models have poor portability, a complex establishment process, and low accuracy. Therefore, establishing a universal and high-precision heat conduction model is significant in guiding module thermal design. This paper demonstrates a three-dimensional Cauer thermal circuit model with clear physical meaning for the double-sided heat dissipation power module used in electric vehicle motor controllers. First, based on the module's internal temperature and heat flux density distribution rules, the concepts of longitudinal thermal resistance and transverse diffusion thermal resistance are proposed, and the traditional thermal resistance calculation formula is modified based on the principle of thermal diffusion. On this basis, a wide range of working conditions was established to verify the accuracy and high robustness of the dynamic and static models of the thermal network model, providing a solid basis for the thermal design of power modules and multi-chip parallel thermal decoupling.