Design and implementation of a modified Sheppard-Taylor Power Factor Corrector operating in Discontinuous Capacitor Voltage Mode and very low output voltage level

This paper presents a practical design and implementation of a modified Sheppard-Taylor-based Power Factor Correction (PFC) circuit used for single-phase low-voltage high-current applications. The proposed converter operates in Continuous Inductor Current Mode and Discontinuous Capacitor Voltage Mode (CICM/DCVM). In this mode of operation, the PFC provides zero-voltage turn-off switching, as well as natural input power factor correction over a wide range of input voltage. Due to the simplified control circuit and reduced switch current stress that it yields, this mode of operation offers better efficiency and higher reliability than the CICM/CCVM previously reported in the literature. The performance of the proposed PFC is analyzed through experimental measurements carried out on a 500W laboratory prototype. It is shown that this rectifier exhibits high input power factor and low line current distortion at very low output voltage level.