Active-clamp snubbers for isolated half-bridge DC-DC converters

In conventional isolated half-bridge dc-dc converters, the leakage-inductance-related losses degrade converter efficiency and limit the ability to increase the converters´ switching frequencies. In this paper, a novel active-clamp snubber circuit for half-bridge dc-dc converters is proposed to recycle the energy stored in the leakage inductance by transferring this energy to a capacitor with zero-voltage zero-current-switching switched auxiliary switches, such that body-diode conduction of primary-side main switches are prevented and primary side ringing are attenuated resulting in improved converter efficiency. Principles of operation and simulation analysis are presented and supported by experimental results that show significant improvement in efficiency.