Design and Parameter Sensitivity Analysis of a Heatsink for a Direct Cooled Power Module with a Ribbon Bonded Cooling Structure

Paper in proceedings, 2019

This paper investigates the sensitivity of heatsink design parameters for a novel type of ribbon-bonded direct cooled power module for automotive applications. Multi-parameter analysis of the heatsink geometry is performed with thermally coupled computational fluid dynamic simulations with respect to thermal and fluid performance. The fluid dynamic simulations show that the outlet pressure drop is the most dominant pressure drop of all considered geometries, while the pressure drop due to the ribbon bonded cooling structure of the power module is comparatively low. The thermally coupled simulations of the ribbon bonded cooling structure show that when maximum rated heat flux from the power module is applied, the coolant temperature increases along the cooling channel is in the worst investigated case as high as 36 °C over the module. This leads to an uneven thermal load of the module, where the downstream power switches become the bottleneck. A method to estimate the amount of loss that can be safely dissipated by taking the coolant inlet temperature, flow rate and thermal gradient into account is proposed.