A modified SEPIC converter with soft-switching feature for power factor correction

In this paper, a modified SEPIC converter is presented to function as a power factor corrector (PFC). The modified SEPIC-type PFC not only can achieve unity power factor but reduce dc-link voltage to release component stresses. Therefore, it is suitable for high line-voltage applications. A soft-switching cell composed of an active switch and an inductor-capacitor resonant circuit is embedded into the PFC to obtain zero-voltage switching (ZVS) feature. As a result, the efficiency of the converter is improved significantly. Operation principles are discussed in detail and conceptual key waveforms are also shown in this paper. A prototype is designed, analyzed and implemented. The simulation results and practical measurements have verified the feasibility of the proposed modified soft-switching SEPIC converter.