A Synchronous Rectification Strategy Driven by Current and Digital for Three Phase LLC Resonant Converter

This paper proposes a novel current-digital co-driven synchronous rectifier (SR) strategy for three phase LLC resonant converter. The current transformer (CT) is installed on the secondary side of power transformer to detected current zero-cross point. The primary driving signal is introduced into the SR strategy to determine action switch. Then, the SR driving signal is generated by an “AND” operation between the primary driving signal and the CT signals. The proposed SR strategy need less CTs than current drive strategy and require less computational than digital drive strategy, and thus, it has better application potential in SR strategy. A 15 kW output power prototype is established to verify the effectiveness of the proposed strategy at different frequencies and loads.