Comparison of Different Insulating Liquids for PCB Embedded Power Modules

PCB embedded technology is a promising packaging method for power electronics devices. But the increase of the voltage rating and the cooling needed induce new issues in the insulation and the thermal management. In traditional power modules, thermal and insulation management are decoupled. Using a dielectric liquid could be an interesting solution for addressing both issues simultaneously. In this paper, the insulation management in PCB embedded power modules is investigated under AC 50 Hz high voltage waveform. Partial discharges (PDs) and breakdown voltage (BDV) measurements are performed on PCB substrates which represents the electrical constraints that we could find in a 3D switching cell. The PCB substrate is embedded in three different dielectric liquids: Paratherm, Nytro Taurus and Midel 7131. The results show a better performance in the Midel 7131 based on its PDIV and BDV values. The BDV results show that the agitation of the liquid may have a negative effect on the insulation performance.