Synchronous Rectification Control of CLLC Resonant Converter Based on Resonant Capacitor Voltage

For resonant converters, synchronous rectification (SR) is an effective way to reduce switch conduction losses. In this paper, a synchronous rectification driving strategy based on resonant capacitor voltage is proposed for CLLC resonant converters. Unlike existing SR driving strategies, the proposed method requires neither use costly sensors nor complex theoretical calculations. The control principle of the proposed method at different operating frequencies is analyzed in detail, and a simple implementation control block diagram is established based on the proposed method. Finally, the effectiveness of the proposed SR driving strategy is verified by simulation and experimental results.