Design and implementation of a novel soft-switching half-bridge power factor corrector with output voltage balance control

This paper provides a novel soft-switching half-bridge power factor corrector (PFC) with output voltage balance control using zero-current-switching (ZCS) auxiliary resonant circuits. In proposed soft-switching PFC, ZCS´s on the active switches are achieved without additional current stress. The steady-state analysis is performed for operation illustration and the small-signal analysis is also built up for output regulation control. An average-current-mode for power factor correction is utilized to control the proposed soft-switching half-bridge PFC in the continuous conduction mode. The balance control technique is designed to overcome the two output capacitor voltage imbalance that is inherent in half-bridge topology. The operational principles, design considerations and realizations are discussed and verified. The prototype specification of the proposed soft-switching half-bridge PFC is rated at 400W and operates at 30kHz, with an input ac voltage of 110V_rms and a regulated output voltage 400V_dc, for experiments to verify the theoretic analysis.