A simple AC-DC PWM full-bridge converter with auxiliary transformer winding

A PWM full-bridge converter that integrates the PFC and dc-dc conversion functions in a single stage is proposed in this paper. The main features of the proposed converter include an input high power factor, a low output current ripple, and a primary-side dc bus voltage that can be kept below 450 V over a wide line and load range. These features can be achieved with a simple converter topology that uses an auxiliary transformer winding to reduce the dc bus voltage. In the paper, the operation of the proposed converter is explained, its features and steady-state characteristics are discussed, and general design guidelines are given. The feasibility of the converter, and its ability to meet EN61000-3-2 standards for electrical equipment is shown with results obtained from an experimental prototype.