Single-phase direct AC-DC bidirectional converter featuring natural power factor correction

A single-stage direct ac-dc bidirectional resonant converter is proposed. It features natural power factor correction and theoretically gives rise to an ideal sinusoidal ac current. It confines high-frequency circulating current to one bridge as a means to reduce conduction loss. Zero-current switching is achieved in all ac-side switches while zero-voltage switching is achieved in at least two dc-side switches. Simulation and experimental results are presented to verify the proposed modulation strategy.