A High Efficiency Phase-Shift Full-Bridge Converter With Improved Clamping Circuit to Eliminate Oscillation for EV Battery Charger

In this paper, the phase-shift full-bridge converter with a novel clamping circuit is proposed for an electric vehicle charger. The proposed clamping circuit consists of two capacitors and two diodes, and it can solve the various problem in converter operation including voltage oscillation elimination of rectifier diodes. Thus, the proposed converter can reduce the conduction loss by the low forward voltage drop of the Si diode. Besides, it can utilize more wide voltage gain by reduced the duty-cycle loss and secure enough ZVS energy in constant current mode. Therefore, the proposed converter can achieve high efficiency by reduced conduction losses. The feasibility of the proposed convert has been verified with a 3.3 kW EV battery charger prototype under 385 V input and 270 - 420 V/7.85 A output conditions.