A Single-Stage Interleaved Resonant Bridgeless Boost Rectifier with High-Frequency Isolation

This paper proposes a novel single-phase single-stage ac-dc converter with high-frequency isolation and power factor correction. Unlike the two-stage ac-dc converters, the high-frequency pulsating voltage is obtained directly from the power factor correction semistage and is applied directly to the dc-dc semistage. The proposed topology is designed to be operated in the continuous conduction mode (CCM), and therefore, there is no need for additional input filter. In addition, the interleaving operation helps reducing the current stress and gets a better electro-magnetic interference performance. Moreover, all of the power switches in the proposed topology can achieve soft-switching commutation. Furthermore, the intermediate dc-link capacitor is no longer directly connected to the dc-dc stage and the capacitance can be reduced greatly; therefore, the bulk capacitor is replaced by a film capacitor. Frequency characteristics and time-domain analysis of the LLC resonant tank is presented in this paper to analyze the characteristics of the proposed converter. Finally, a prototype that converts universal input voltage ranging from 110 to 220 V into 400-V dc output was built and tested to verify the analysis.