Design and Fabrication of PCB Embedded Power Module with Integrated Heat Exchanger for Dielectric Coolant

Abstract:
Due to an increasing demand in miniaturization of power converter, power loss densities increase significantly, which makes their thermal management difficult. One way to face this challenge is PCB embedding of semiconductors. This approach provides a much shorter thermal path from semiconductor to a coolant, than with a usual DBC-based power module. Still, a typically liquid cooling heat exchanger, which is connected to the power module forms a main part of the overall thermal resistance. This paper presents a novel design of a PCB embedded power module with a small size heat exchanger. To meet the requirements of the targeted application a dielectric coolant was used. A parametric study was performed to find out the most suitable cooling concept. Jet impingement on an optimized cooling surface with an increased area is persecuted. The heat exchanger design is described and the thermal performance is evaluated by CFD-simulations. The overall thermal resistance for the IGBT was calculated to Rth junction-coolant = 0.52 K/W. For comparison a reference DBC-based power module on a standard cold plate is considered. Its thermal resistance was Rth junction coolant = 1.03 K/W which is almost two times higher than the embedded version with direct cooling.