An Improved AC–DC Single-Stage Full-Bridge Converter With Reduced DC Bus Voltage

A new ac-dc single-stage voltage-fed pulsewidth-modulation (PWM) full-bridge converter is proposed in this paper. The converter can simultaneously perform input power factor correction and dc-dc conversion using conventional phase-shift PWM and can maintain a primary-side dc bus voltage of less than 450 V even at a high input line voltage of 265 V_rms. This is a combination of features that few, if any, other converters of the same type have. The proposed converter has these features due to the novel implementation of an asymmetrical auxiliary transformer winding that is placed in series with the input inductor and acts as a boost switch. In this paper, the operation of the proposed converter is explained in detail, its outstanding features are discussed, and a detailed design procedure is given and demonstrated with an example. Experimental results that confirm the feasibility of the converter and its ability to meet IEC1000-3-2 Class D standards for electrical equipment are also presented in this paper.