Reduced redundant power processing (R2P2) PFC voltage regulators: Circuit synthesis and control

High input power factor is becoming a mandatory requirement, in addition to tight output regulation, of dc power supplies that derive power directly from the ac mains. In principle, the power factor correction (PFC) and output regulation functions are separately achieved by two power stages. This paper addresses the amalgamation of the two power stages to form a PFC voltage regulator. The focus is the non-cascading structure that allows a higher overall efficiency to be achieved. Unlike the conventional cascade configuration, the circuits discussed in this paper allow part of the input power to be processed by only one stage, thereby reduce the amount of power redundantly processed by the two constituent power stages. This paper describes in particular a systematic synthesis method and some important issues related to the control of such converter circuits.