GaN Dual-Stage Power Supply

Current military vehicles use commercial-off-the-shelf (COTS) inverters to provide power from their 28 Vdc bus to 120 Vac loads. These COTS inverters are large and inefficient and do not meet all of the requirements for military grade electronics. This proposal details efforts to develop an isolated, two-stage GaN based power supply for military vehicles to reduce volume and weight, as well as increase efficiency compared to the legacy system. Mainstream proposes a two-stage 2.5 kW power supply with an isolating zero-voltage-switching dual-active-bridge (ZVS DAB) dc-dc front end and an H-bridge inverter back end, both built using high-current GaN devices. The proposed power supply places multiple GaN dies on a Thermal Clad substrate with integrated cooling: reducing the thermal resistance by an order of magnitude over standard PCB based approaches. The power supply has less than 2% THD at the output and has zero-percent de-rating at 71 C ambient temperature. The resulting power supply has a 75% reduction in volume, 42% reduction in weight, and greater than 4% improvement in efficiency compared to the legacy system. At the completion of the Phase I, Mainstreams GaN dual-stage power supply will be a Technology Readiness Level (TRL) 4.