Bridgeless Single-stage Step-down Power Factor Corrector under Synchronous Switching Control Scheme

In this paper, a novel bridgeless power factor corrector (PFC) is proposed. The PFC can shape the waveform of the input current to be sinusoidal and in phase with the AC input voltage simply by sensing of the AC voltage, input current, and output voltage. That is, it is able to achieve a unity power factor. As compared with conventional PFCs, the proposed PFC possesses the particular features of high step-down voltage ratio, being bridgeless, galvanic isolation, and leakage energy recycling. All the active switches in the proposed PFC can be operated under an identical control signal. In addition, the output voltage can be regulated only by single-loop control, instead of dualor multiloop control. Therefore, the control scheme for the PFC is simple and much easier to carry out. The operation principle, theoretical analysis, and hardware validation to verify the proposed PFC are described.