Thermal-Electrical Modeling and Co-Optimization of a Half-Bridge Power Module With Silver- Sintered Molybdenum Packaging

This article proposes a methodology of analytical modeling and optimization of power modules, especially compatible with modules with silver-sintered molybdenum (SSM) packaging or other insulated metal substrate types of packaging schemes. First, a decoupled Fourier-based thermal model is presented, which considers the barrier effect between substrate segments. Compared with the original Fourier-based model, it reduces the average error from 93.8% to 10.9%, when estimating the difference of junction temperatures (T-j) for power modules with asymmetric substrates. Then, a stray inductance (L-s) model is developed based on the partial inductance method and the actual current distribution, whose error is less than 12.1% when tested with example half bridge SSM modules. Next, analytical models are combined with the particle swarm optimization algorithm to design a half-bridge power module with SSM packaging. Numerical simulations prove that the analytical estimations of T-j and L-s of the optimized module are accurate, with errors of 4.6% and 8.3%, respectively. The fabrication process of the designed SSM module is then elaborated. Finally, the accuracy of L-s estimation is validated by the double pulse test, where the error is 0.4%. The junction-to-case thermal resistance is characterized by the structural function analysis, in which the error is 3.4%