Research on GaN Digital DC/DC Power Supply for Aerospace Applications

This paper investigates the design requirements for GaN power devices and digital DC/DC power supply for space power applications, including blocking voltage level, heat resistance, anti-irradiation capability, etc. Designed and validated a single event effect (SEE) capability of up to 75MeVcm²/mg for radiation hardened GaN devices by using double heterojunction structure and filed plate to increasing breakdown voltage and reducing gate leakage current. A radiation-hardened GaN DC/DC is proposed based on an independently-developed high electron mobility transistor (HEMT) which is suitable for satellite electrical power distribution system. The DC/DC adopts a buck-boost and LLC topology to achieve a wide input range. Using techniques such as ZVS, transformer optimization, and dedicated wiring, the switching frequency is 3Mhz, the output power is within 200W, and the efficiency is 85.7%. Considering the high reliable requirements of space, thermal and radiation tests were conducted to verify its correctness. Compared with traditional Si-based DC/DC using in satellite electrical power distribution system, GaN-based DC/DC has significant improvements in power density and output efficiency, making it suitable for miniaturized and lightweight satellite power distribution system applications. Finally, design improvement ideas are proposed to provide support for space applications.