GaN-based ZVS Bridgeless Dual-SEPIC PFC Rectifier with Integrated Inductors

This paper investigates the gallium nitride (GaN) based bridgeless dual single-ended primary inductor converter (SEPIC) power factor correction (PFC) with full input voltage range zero-voltage-switching (ZVS) turn-on for the application of step down AC-DC converter. The operation principles for the bridgeless Dual-SEPIC PFC and the theoretical analysis for the ZVS operation has been investigated. Furthermore, a new magnetic integration has been proposed to assemble all three inductors, including one input inductor and two output side inductors into one E-I-E core. The integrated inductor reduces the total ferrite volume and makes the converter more compact. The inductance design for ZVS SEPIC PFC and the magnetic reluctance modeling for the E-I-E core with the coupled inductor has been analyzed. The effective equivalent inductance of the input inductor can be implemented with a much less number of turns by a carefully designed coupling coefficient. Finally, a 300W GaN-based MHz bridgeless Dual-SEPIC PFC with the integrated inductors is developed and tested with fullrange ZVS, 97% peak efficiency based on the ZVS extension strategy.