Control of Single-Stage SR-DAB-Based Bidirectional AC/DC Converter With Simplicity and High Accuracy

A novel control under extended phase shift combined with variable frequency modulation is proposed for single-stage ac/dc converter based on a series resonant dual active bridge. Based on fundamental harmonic analysis (FHA), a simple control algorithm for internal/external-shift-phases and switching frequency is proposed to achieve PFC, near-minimum tank current and ZVS-on of all switches. To improve the accuracy of currents at turn-on instants for ZVS, the FHA-based control variables are fine-tuned in a closed-loop way based on time domain analysis. Simulation and experimental results are presented to verify the proposed control.