Research on Thermal Coupling Modeling for Multi-chip Paralleled IGBT Modules Based on Thermal Resistance Network

In a power inverter system, IGBT modules are located on the same cooling system, which form multiple heat sources that contribute to the total heat generation. When heat transfers from chips to cooling system through baseplate, thermal coupling will be generated between paralleled IGBT modules. Based on thermal resistance network method, a thermal coupling model to calculate the resistance and junction temperature is built up, considering the thermal coupling between the paralleled IGBT modules. The formula to calculate thermal coupling resistance among IGBT modules is derived. The proposed method is applied to a case study of a 1700V/1400A IGBT module and three-dimensional model of the IGBT modules is built up. To validate the thermal coupling model, the simulation of a three-phase power inverter is established in Infineon-IPOSIM and the proposed method in different output current. The junction temperature in the simulation has a good agreement with the proposed method.