Analysis and design of zero-voltage-switching current-fed isolated full-bridge Dc/Dc converter

This paper presents steady-state analysis and design of current-fed full-bridge dc/dc converter with active-clamp. The converter utilizes the energy stored in the transformer leakage, aided by its magnetizing inductance to maintain zero-voltage- switching of H-bridge switches over wide range of input voltage and load variation. Active-clamp clamps the voltage across the switches at turn-off, allowing the selection and use of low voltage devices with low on-state resistance. In addition, this small and low rating active-clamp circuit results in zero-voltage transition circuit aiding in achieving zero voltage switching of the devices. All switches undergo soft turn-on and switching losses of the converter are reduced. It improves the converter efficiency and allows high switching frequency operation, which results in compact, light weight, and low cost system.