A Single-Stage Three-Phase AC-DC Converter with Ripple Voltage Self-Offset

This paper proposes a novel single-stage, shared-switch, series-output three-phase isolated AC-DC converter with ripple voltage self-offset (S6-RO). By merging the primary-side switches of the resonant converter and the three-phase rectifier, the topology eliminates six transistors compared to a traditional input-parallel output-series (IPOS) configuration. The series connection of the outputs, combined with the natural 120° phase shift of the three-phase rectifier, reduces ripple voltage without requiring complex modulation schemes. We provide an analysis of the operating modes and input components for the resonant tanks, develop its fundamental harmonic approximation (FHA) model, and introduce a modulation technique. A design guide is included, and experimental validation using a 1 kW, 45 kHz prototype demonstrates the effectiveness of the proposed topology.