Design and efficiency measurement of a sub-unit for a 20kW DC-DC multiphase power converter

This paper explores various design strategies for low-voltage, high current DC-DC converters, in order to optimize efficiency, volume, and mass, while keeping the project as simple and cost efficient as possible by using only on-the-shelf components, including inductor and heatsinks. The impact of topologies on both efficiency and compactness is studied for a specific aeronautical application. A 2kW 3-level FCML module has been developed for a 100V to 28V DC-DC step-down. It relies on pairs of paralleled EPC2022 GaN transistors to significantly increase converter power density. Two routing strategies to reduce parasitic switching loops are compared using computer simulations, with experimental verification. First experimental results on a prototype show an efficiency up to 98.4% for a specific power of 12.5kW/L.