A novel resonant transition half-bridge converter

Resonant transition converters are characterized by low switching losses and low conduction losses. This paper proposes a novel half-bridge resonant transition converter with soft switching properties. The improvised half-bridge converter uses two additional switches and two diodes. The additional switches introduce freewheeling intervals in the primary circuit and thus enable lossless switching. In classical half-bridge converter, the transformer primary is left open during two subintervals in a period. On account of this feature, the turn-on of the switch in these converters is always hard. The new circuit topology converts these open circuit intervals into freewheeling intervals with such a modification, all trapped energy in the core is conserved to achieve ZVS during all the switching transition. The principle of operation of the proposed topology is explained. Design procedure is explained. Design procedure is validated through a prototype converter rated 300 kHz, 640 W half-bridge converter.