An Improved Duty Cycle Generation Scheme for the Three-Phase Single-Stage PFC in Unbalanced-Grid

An improved duty cycle generation scheme is proposed and designed in this paper to overcome the operational problems of the three-phase PFC converter based on the isolated full-bridge topology in the unbalanced-grid condition. Input current of this three-phase converter in the special unbalanced condition is analyzed according to that in the balanced condition, based on which, its duty cycle is regenerated to achieve a better three-phase power factor of this converter in the unbalanced-grid condition. Finally, the proposed scheme and analysis are verified by the simulation and experiment.