High efficiency PFC with Enabling Window Control and active input bridge

Conventional CCM Boost (CB) PFC has been widely used for the PFC applications because of its high input power factor and simplicity, but it suffers from conduction loss in the input rectifier bridge and switching loss due to the high switching frequency. The efficiency decreases significantly under the low input voltage or the light load work condition. In this paper, a novel Enabling Window Control (EWC) method is proposed to reduce the switching loss, and an active input bridge is used to replace the traditional diode bridge for high efficiency. The principle and design of proposed method is presented, furthermore, the validity of the proposed method is verified by experimental results obtained from a 500W prototype.