一种双变压器结构的多谐振型软开关直流变换器

A Dual Transformer-Structured Multi-Resonant Soft-Switching DC-DC Converter

提出一种双变压器结构的多谐振型软开关直流变换器。通过在谐振腔内引入辅助高频变压器,变换器获得了包含谐振零点在内的多个谐振频率点。通过合理配置谐振点位置,变换器可在较宽频率范围内保证基波和3次谐波有功功率的同时传递,提高谐振电流利用率并起到抑制无功环流的作用。同时,谐振零点的引入使得变换器具备固有的限流保护能力。此外,变换器能够在全负载范围内实现开关管的零电压开通、二极管的零电流开通和准零电流关断,减小了开关损耗。最后,为了验证所提拓扑的有效性和参数设计方法的合理性,搭建一台额定功率330W的样机进行实验验证,最高效率可达到94.7%。

A dual transformer-structured multi-resonant soft-switching DC-DC converter is proposed in this paper.Through the introduction of high-frequency transformers into the resonant tank,the converter obtains several resonant points including a unique resonant zero point.By properly configuring the resonance point position,the converter is able to transmit the 1st and the 3rd harmonic active power simultaneously in a wide frequency range.Thus,it contributes to the improved utilization rate of the resonant current and the reduced reactive circulation in the resonant tank.Moreover,inherent over-current protection is also obtained for the converter thanks to the adoption of the resonant zero point.Besides,the converter achieves the excellent turn-on zero-voltage switching(ZVS)for all the power switching devices in the primary side.Meanwhile,all the diodes in the secondary side realize the turn-on zero-current switching(ZCS)and turn-off zero-current quasi-soft-switching(Q-ZCS).Therefore,high conversion efficiency is assured due to the switching loss restricted effectively.To verify the feasibility of the proposed converter and the rationality of parameter design method,a 330W prototype is built in the laboratory.The maximum efficiency is 94.7%for experimental tests.