Analysis of a DC/DC converter with wide ZVS range and low circulating current

This paper presents a new zero voltage switching (ZVS) converter with the full-bridge and halfbridge circuits. The main advantages of the proposed converter are wide ZVS range for all leading-leg and lagging-leg switches, low circulating losses and low output inductor size. The drawback of narrow ZVS range of lagging-leg switches in conventional phase-shift pulse-width modulation full-bridge converter is improved by adding a half-bridge circuit shared the lagging-leg switches with the full-bridge circuit. Therefore, all switches in the proposed converter can be turned on at ZVS from low light to full load. The output of half-bridge converter is connected to the secondary side of the full-bridge converter in order to generate a positive voltage instead of zero voltage at the secondary rectified point. Hence, the high circulating losses in conventional full-bridge converter is overcome and the output inductor current ripple is also reduced. Finally, the theoretical analysis and performance of the proposed converter are verified by the experimental results from a 1.44kW prototype.