Zero-Voltage-Switching Asymmetrical PWM Full-Bridge DC-DC Converter With Reduced Circulating Current

In the article, an asymmetrical pulsewidth modulation (PWM) full-bridge converter with zero-voltage-switching (ZVS) and reduced circulating current is proposed. For the conventional phase-shift full-bridge converters, the circulating current in the primary side of the transformer degrades the efficiency. The converter cannot meet a high efficiency in the wide input or output voltage range. In order to reduce the circulating current, the modified full-bridge dc-dc converter with the split capacitors and improved rectifier stage is controlled by the asymmetrical PWM. The two transformers in the proposed converter share the output power equally, so the volume of the transformers is easy to optimize. Furthermore, all the switches can still achieve the ZVS performance. Besides, the proposed converter can reduce the current ripple of the filter inductor, leading to a reduction in output filter inductance. Finally, a 1-kW prototype is built to verify the proposed converter. The performance is compared with the other full-bridge dc-dc converters.