Soft-switching single-stage current-fed full-bridge isolated converter for high power AC/DC applications

In this paper, a novel single-stage softswitching current-fed full-bridge AC/DC converter is proposed. By adding an additional commutation path, softswitching can be realized for all power devices. The power density is also enhanced by eliminating the DC capacitor. Meanwhile, the conduction loss is also lowered through the use of the additional commutation path. Furthermore, the control strategy for the proposed converter is compatible with that for traditional PFC converter. This facilitates the use of well-developed analog control IC such as UC3854. In this paper, the topology derivation and circuit operational analysis are given. The control strategy is introduced. A simulation is carried out to verify the circuit functionality.