An optimized modulation method tor full-bridge/push-pull bi-directional DC-DC converter with wide-range ZVS and reduced spike voltage

An optimized modulation is proposed for the bidirectional DC-DC converter based on the full-bridge/push-pull circuit. With the proposed strategy, the zero-voltage-switching (ZVS) range of the lagging-leg switches in the conventional full-bridge topology can be extended. Moreover, severe voltage overshoots across main switches caused by the leakage inductance of the transformer in the current push-pull circuit are suppressed. Furthermore, the modulation is unified for both the buck mode and the boost mode, which is easy to realize compared with the conventional methods. In addition, no auxiliary circuits are employed, resulting in low cost and small volume. Detailed analysis and design of the proposed modulation are described. The simulation results validate the operation principle and a kW prototype is built to show the effectiveness of the proposed strategy.