Pin-Fin Design and Optimization for Direct Cooling of Electric-Vehicle Traction Inverters

A methodology of pin-fin design and optimization for power-semiconductor modules of electric-vehicle traction inverters is presented, including application examples and experimental verification. The method consists of four independent steps. A first one utilizes analytical models based on correlations and allows to determine the best pin field and flow configuration. In step 2, the correlation-based model is coupled with a 3D conduction model in order to account for thermal spreading effects. In step 3, conjugate-heat-transfer simulations are performed to study the details of flow and heat transfer around the pins and the sources of pressure drop including inlet and outlet channels. Finally, step 4 comprises the experimental verification of thermal performance and pressure drop. An example is presented showing how the optimization in this approach can reduce the temperature inhomogeneity between parallel-connected power semiconductor chips by 10 K. This is achieved taking particular account of the inhomogeneity in heat spreading due to substrate layout and copper traces.