基于移相全桥的两级式交错并联DC/DC拓扑研究

Principle and control of two-stage interleaving DC/DC topology based on phase-shift full bridge converter

针对电动汽车的快速、安全、高效充电等热点问题,提出了并联型DC/DC全桥与降压型变换器拓扑相结合的控制策略,利用移相全桥控制技术和交错并联控制技术,实现高频磁隔离功能,提高电流控制性能,提升整个系统效率。详细介绍了两级式DC/DC变换器的拓扑结构和工作原理,前级移相全桥电路通过移相控制实现软开关功能,并降低开关损耗,而后级降压电路可以实现闭环控制,输出固定电压。由此表明交错并联技术能够使输出电流纹波得到有效抑制,从而输出更高功率。本系统基于TMS28335进行软件设计,研制出一台最大输入电压为700 V,输出电压为250~550 V的5 kW变换器,验证了所提出控制策略的可行性。

Aiming at the hot issues of fast,safe and efficient charging of electric vehicles,a control strategy combining the parallel DC/DC full bridge and buck converter topology was proposed.The phase-shifting full bridge control technology and interleaved parallel control technology were used to realize the high-frequency magnetic isolation function,and the current control performance and the efficiency of the whole system were improved.The topology and working principle of the two-stage DC/DC converter were introduced in detail.The soft switching function was realized by the front phase shifted full bridge circuit through phase-shifting control and the switching loss was reduced.The latter step-down circuit could realize closed-loop control and output fixed voltage.The results show that the interleaved parallel technology can effectively suppress the output current ripple,so as to output higher power.Based on TMS28335,a 5 kW converter with maximum input voltage of 700 V and output voltage of 250-550 V is developed.The feasibility of the proposed control strategy is verified.