Soft-start Active-clamp Isolated Full-bridge Current-fed DC-DC Converter

The conventional isolated full-bridge current-fed (FB-CF) DC-DC converter suffers two critical problems, voltage spike across switches and inrush current at start-up. This paper proposed a method for an active-clamp FB-CF converter. The proposed converter can solve both critical issues with the suggested method without any auxiliary circuit or extra components. The operation of the converter is investigated under both steady-state and start-up periods. The method is verified by simulation and experiments with a 1 kW prototype.