3D Thermal Simulation of Power Hybrid Assemblies

Among the main factors to be considered for the thermal optimisation of hybrid power modules are: the thermal resistance between the power chips and the bottom of the case; the thermal coupling between adjacent chips; and the ability of the module to withstand the thermal overloads induced by electrical surges. In this paper, the authors show how a finite element code can be used to optimise a hybrid power assembly in both steady‐and unsteady‐state. Comparisons made between results obtained with 3D and 2D simulations show that for hybrid power modules 2D simulations are generally unreliable. However, thermal studies cannot guarantee the reliability of hybrid power assemblies. Studies relative to hybrid power circuits must be thermomechanical.