A 3-D Thermal Network Model for IGBT Modules Considering Temperature Dependence of Heat Dissipation and Thermal Coupling

Three-dimension (3-D) thermal networks have the advantages of quick and accurate calculation for junction temperatures of IGBT modules. However, in order to calculate the junction temperature accurately under different working conditions, multiple boundary conditions should be considered, resulting in repeated modelling process and complex model structure. A 3-D thermal network model considering the temperature dependence of heat dissipation and thermal coupling is proposed in this paper. The impact of boundary conditions on heat dissipation and thermal coupling is approximately equivalent to the impact of material temperature on thermal conductivity and convective heat transfer coefficient. The temperature dependences of self and coupling thermal impedances are integrated in the 3-D thermal network, avoiding repeated calculation. The accuracy for junction temperature calculation with the proposed 3-D thermal network is verified by finite element method (FEM) simulation. The proposed model provides a rapid modeling method which also ensures adequate accuracy for junction temperature calculation.