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To reduce the intermediate storage capacitor voltage stress in single-stage power-factor-corrected (S2PFC) converters due to the change of load, some effective approaches such as variable frequency control and negative bus voltage feedback have been proposed. However, this intermediate capacitor voltage still varies largely against the change of line voltage. This paper proposes a S2PFC converter which is constructed in a way such that the amount of energy to and from the intermediate storage capacitor can be varied when the line voltage is changed, hence narrowed the range of intermediate capacitor voltage fluctuation. This is achieved by an auxiliary bidirectional switch, which operates at zero-voltage-switching (ZVS) condition. A dual-loop voltage mode control is proposed for the converter to achieve power factor correction, output voltage regulation, and intermediate capacitor voltage control simultaneously. Simulation and experimental results show that the proposed approach is effective. [ABSTRACT FROM AUTHOR]

In this paper, a new family of single-stage AC/DC power factor correction converters (S2PFCC), which possesses reduced voltage stress across the storage capacitor and no extra current stress on the power switch, is proposed. The converters are realized by reduced repeated power processing concept in which part of the input power is transferred to the load directly after the first power process. This results in lower storage capacitor voltage than that of previously developed S2PFCCs but maintaining high power factor. In addition, the inherent input current control allows the load current to reduce the input line current automatically when the load becomes light, preventing excessive amount of energy being stored in the storage capacitor. Although the proposed converters employed two power switches, a simple single-loop controller for the proposed S2PFCC to achieve power factor correction (PFC) and tight output regulation is also proposed. Experimental results are reported to verify the operation and concept of the new S2PFCC. [ABSTRACT FROM AUTHOR]