A High-Efficiency Single-Phase AC/DC Converter With Enabling Window Control and Active Input Bridge

The conventional continuous conduction mode boost converter has been widely used for power factor correction (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 introduced to reduce the switching loss, and an active input bridge is used to replace the traditional diode bridge for high efficiency. The proposed EWC method is easy to implement with existing PFC ICs, and only a few additional control components are needed. Moreover, electromagnetic interference noise and driving loss of the main switch can be reduced with the EWC method. Semiconductor devices with competitive price can be used to reach efficiency as high as SiC diode and Cool-MOSFETs. A self-driven circuit is also used for the active bridge. The principle and design of proposed method are presented and the validity of the proposed method is verified by experimental results obtained from a 500-W prototype.