Single-stage immittance-based three-phase AC-DC bidirectional converter and PWM strategy for realizing zero circulating power

A new single-stage three-phase resonant ac-dc quad-active-bridge (QAD) converter is proposed. It uses a new modulation scheme designed for use with a tuned LCL resonant network that achieves unity power factor at both network ports, which leads to reduction in rms bridge currents and conduction loss. The line-frequency phase currents are individually controllable by modulating the ac-side and dc-side switches according to user-prescribed current references.