Active-clamped ZVS current-fed push-pull isolated dc/dc converter for renewable energy conversion applications

This study introduces a new active-clamped current-fed push-pull dc-dc converter for renewable energy conversion applications. The proposed converter conserves small input current pulsation, high-voltage conversion ratio, zero-voltage switching (ZVS) and zero-current-switching operation for primary switches and rectifier diodes, respectively, over a large load range. Also, the additional active clamping circuit serves to suppress the voltage spike across all primary switches, as well as assists in achieving ZVS operation. So, the low-voltage switches with low on-state resistance can be adopted. These features can reduce switching loss, voltage stress, transformer turns ratio and diode reverse-recovery effect. More importantly, similar characteristics can be obtained with minimised switches compared with the reported converters that enable to reduce the cost and improve the reliability. Detailed steady-state operation, analysis, performance comparison, experimental results and loss breakdown of the proposed converter are fully discussed in this study. Finally, a 520W prototype verifies the theoretical analysis.