A Study on Single-Switch Single Power-Conversion PFC Converter with Regenerative Snubber

Abstract

This thesis proposes a single-switch single power-conversion (S3PC) power factor correction (PFC) converter with a regenerative snubber. Using only a single switch, the S3PC converter can perform both PFC and output power control through single power-conversion. Thus, the proposed S3PC converter achieves high efficiency and simple structure. The proposed S3PC converter has two features: series-resonance and regenerative snubber. The series-resonant circuit provides zero-current switching turn-off for the output diodes, so that reverse-recovery problem of output diodes is reduced. Also, by using the characteristic of bidirectional core excitation acquired from series-resonant circuit, the S3PC converter provides higher power capability compared to the conventional single-switch PFC converters. The regenerative snubber not only clamps the voltage spike of the switch but also recycles the absorbed energy. Because these features are obtained with only a single switch, the S3PC converter achieves both high efficiency and simple structure. To perform both PFC and output power control through single power-conversion, a control algorithm is developed for the S3PC converter. This control algorithm is derived from feedback linearization and enables the proposed converter to obtain acceptable controllability and to operate in the continuous conduction mode without any auxiliary circuit. Namely, with this control algorithm, the S3PC converter carries out single power-conversion and ensures high power factor and low total harmonic distortion. With aforementioned advantages, the S3PC converter provides high efficiency and high power quality. In this thesis, the operational principles and the control algorithm of the S3PC converter are discussed in detail. Also, design guidelines for the series-resonant circuit and the regenerative snubber are provided. Experimental results for a 1-kW prototype are used to demonstrate the validity and the performance of the proposed S3PC converter.