Light-Load Efficiency Enhancement of High-Frequency Dual-Active-Bridge Converter Under SPS Control

Dual-active-bridge (DAB) converter is an attractive topology to be used as a dc transformer (DCT) in the power distribution system. Because voltage gain for relatively fixed, single-phase-shift (SPS) control popularly adopted DAB achieve simple control. Aiming at increasing light load efficiency of high-frequency under SPS control, this letter proposes concept full range zero-voltage-switching (ZVS) with minimum rms current certain variation range. In proposed method, added magnetizing inductance creates possibility ZVS all switches. The specially controlled by turns ratio, which no longer conventional unity condition. key parameters optimization, including inductance, and leakage transformer, introduced based on stress analysis. A 250 kHz, 400/48 V, 1000 W GaN-based prototype built, shows performance improvements load.