基于GaN器件的直流配电网用户侧DC/DC变换器设计

隔离型DC/DC变换器连接低压直流配电网和用户侧直流负荷，在低压直流配电系统中起着重要作用, 对其效率和功率密度提出更高的要求。本文采用具有原边开关管零电压开通和副边整流管零电流关断特性的LLC谐振变换器，首先分析变换器的工作原理，对其谐振参数进行选择。使用具有更低的导通电阻和等效输出电容的氮化镓器件作为原边开关管，进一步提高变换器工作频率和效率，降低磁性元件体积。在此基础上，对GaN器件驱动、同步整流和磁性元件进行优化和设计。最后搭建了一台375V/48V/500W的LLC谐振变换器样机，最高效率为97.6%，验证了设计的正确性。

Design of GaN-based user side DC/DC converter in DC distribution network

The isolated DC/DC converter connects the low-voltage DC distribution network and the user-side DC load serving as an important equipment in LVDC distribution network and has higher requirements on its efficiency and power density. In this paper, LLC resonant converter with zero voltage switching on primary side and zero current switching on secondary side is adopted. The operation principles of LLC resonant converter are analyzed and the resonant parameters are presented. The gallium nitride device with lower on state resistance and effective output capacitance is used as the primary side switches to achieve higher switching frequency, efficiency and smaller magnetic component volume. Then, the driver of GaN devices, synchronous rectification and magnetic components are optimized and designed. Finally, a 375V/48V/500W LLC resonant converter prototype tested with a peak ef-ficiency of 97.6% is built to verify the correctness of the design.