A Fast Loss and Temperature Simulation Method for Power Converters, Part II: 3-D Thermal Model of Power Module

This paper describes the development and implementation of an analytical 3-D thermal model for fast and accurate thermal simulation of power device modules in electrothermal converter simulation. A Fourier-based solution is used to solve the 3-D heat equation. The solution can describe the variation of temperature through the whole inverter power module structure as a function of time. The model can simulate thermal interactions resulting from multiple heat sources. The thermal model is extremely fast to simulate compared to finite-element (FEM) approaches. The new model has been implemented in MATLAB/Simulink in order to cosimulate with the converter model which is in the same form. The model has been validated against the computational fluid dynamics (CFD) software package FLOTHERM and shows good agreement. The required aspects of 3-D heat diffusion are captured successfully by the Fourier-based model.