An Isolated Active-Clamped Circuit Current-Fed Half-Bridge Converter

This paper presents an isolated regenerative active-clamped circuit designed for the current-fed half-bridge (IRACCFHB) converter. Its primary function is to reduce high voltage spikes across the main switches caused by energy stored in the leakage inductance of the power transformer using a clamping capacitor. This recovered energy is delivered efficiently to the load, maintaining the converter's high efficiency and voltage ratio. The proposed auxiliary circuit employs a single active switch with the same ground reference as the main switches, eliminating the need for an isolated gate driver. The converter achieves zero voltage switching (ZVS) during the turn-off of the main switches and zero current switching (ZCS) during the turn-on of the auxiliary switch. Energy recovery to the load is accomplished without compromising galvanic isolation due to employing a coupled inductor in the auxiliary circuit. To validate the proposed analysis and design, a $350~\mathrm{W}$ prototype was implemented.