一种低环流损耗的宽范围ZVS移相全桥变换器

Wide-Range Zero Voltage Switching Phase-Shifted Full-Bridge Converter with Low Circulation Loss

传统移相全桥变换器广泛应用于中、大功率DC-DC变换场合,但掉电保持要求限制了它在正常工作时的占空比,增加了一次侧环流损耗。针对该问题,提出一种减小环流损耗的新型软开关全桥变换器。通过在一次侧引入辅助耦合电感和辅助电容,二次侧引入辅助绕组和辅助开关管,该变换器不仅一次侧环流损耗得到大大的降低,而且一次侧开关管在全负载范围内也能够实现零电压开关(ZVS),进一步提高了变换器的变换效率。文中阐述了该变换器的工作原理和特性分析,并通过一台120W/24V、开关频率为100k Hz的原理样机验证了该变换器的优点。

A new high-efficient phase-shifted full-bridge （PSFB） converter is proposed in this paper. The conventional phase-shift full-bridge converter gains more attentions in medium or high power applications, because of its features high conversion efficiency and high power density. However, the hold-up-time requirement limits its operating duty ratio in normal state, and the conduction loss increases caused by circulating current. Therefore, by introducing the auxiliary coupled inductor and the storage capacitor at primary side, as well as the auxiliary winding and the auxiliary switching at secondary side, the proposed converter can not only achieve the ZVS operation in the full load range but also reduce the conduction loss. Finally, the operational principle and analysis of the proposed converter are presented and verified by the 120W/24V, 100kHz prototype.