A novel full-bridge converter achieving ZVS over wide load range with a passive auxiliary circuit

摘要

A novel full-bridge converter is proposed in this paper, which achieves ZVS over the entire conversion range with a passive auxiliary circuit. The stored energy in the auxiliary circuit is minimal under the full-load condition and it progressively increases as the load current decreases. The proposed auxiliary circuit is passive, simple and can be viewed as an add-on to the conventional ZVS FB converter. The steady analysis and operating principle are demonstrated. Based on the analysis, a criterion of optimal design is given. A 1kW full-bridge converter is built to verify the effectiveness of the proposed converter.