Analysis and design of a single-stage ZCS quasi-resonant AC/DC converter with low DC link capacitor voltage

Abstract

An analysis and design of a single-stage zero-current-switching(ZCS) quasi-resonant ac/dc converter with low dc-link capacitor voltage is presented. It has many advantages such as simple circuit, cost-effective, and high power density for low power applications. The proposed converter can effectively reduce the voltage stress on the dc link capacitor and can achieve the power factor correction(PFC) without a dead band at line zero-crossings, which improves the harmonic distortion in ac line current. Furthermore, it is possible to reduce the power loss of a semiconductor power switch by making use of zero-current switching quasi-resonant operation. Theoretical analysis of the converter is presented and design guidelines for selecting circuit components are given. The experimental results on a 75 W(15 V, 5 A) maximum switching frequency of 300 kHz show that maximum dc-link capacitor voltage and maximum efficiency are 446 V and 78 %, respectively. The power factor is above 0.96 under universal line input.