Step-up ZVS full-bridge converter with primary-side loss reduction

A step-up ZVS full-bridge (FB) converter with a primary-side energy recovery circuit (PERC) is proposed. The PERC means can recover the power loss due to high spike current hiding in primary inductance when the phase-shift switching activates. High ringing currents occurring at the beginning of the two resonances each half-period can then be smoothly transferred to DC bus and restrain the resonant current profile from spike current, that provides normal operation for step-up mode conversion. High power efficiency up to 87%-97% is achieved for wide load range by PERC means, which improves efficiency over 3-5% than the conventional case. A practical 400 W step-up ZVS FB converter with PERC is realized to assess the conversion performance and compare with the prior works.