Soft-switched low-cost single phase high quality rectifier circuits with minimum voltage stress across the switches

This paper presents a family of circuits for single phase diode rectifiers capable of drawing approximately sinusoidal current waveforms at unity power factor with high efficiency and minimum voltage stress across the switches. Moreover, they are suitable to work as boost and flyback converters. These topologies use coupled inductors with capacitor for resonance to achieve zero voltage switching (ZVS) of the converters. The circuits consist of a single-phase diode bridge rectifier, followed by a boost stage containing a single switch with zero current switching (ZCS) for turning on and ZVS as well as ZCS for turning off. The output voltage is regulated by employing variable frequency control. The paper explains the principle of operation and describes the analysis of each mode of operation for both boost and flyback converters. It also gives design criteria, derived from the mathematical analysis carried out, for achieving ZVS under all loading conditions from no load to full load. The simulation results obtained using PSPICE demonstrate the validity of the proposed converters.