一种提高电动汽车充电机轻载运行效率的方法

An approach to improve efficiency of EV charger under light load

本文提出了一种提高电动汽车充电机轻载运行效率的方法。在分析原有充电机轻载运行状况的基础上,提出了一种以电容-二极管-有源开关钳位电路代替原有钳位电路的全桥移相式零电压零电流开关(ZVZCS)变换器拓扑,分析了其工作原理并给出了轻载判断条件,进行了仿真研究和样机功率实验,给出了实验结果及波形。结果表明,改进电路既保留了原钳位电路的优点,又在轻载时提高了整机工作效率,同时降低了器件应力。

This paper presented an approach to improve efficiency of EV batteries charger under light load. On the basis of analysis on the original charger built upon capacitor-diode-diode clamp circuit, a modified capacitor-diode- switching clamp circuit was designed to replace the original one in the full-bridge phase-shifted zero-voltage and ze- ro-current-switching PWM DC/DC converter. Operating principle was introduced, and the critical condition to judge whether under light load was derived. Circuit simulation and experiment on the prototype were performed un- der different load. Both results show that besides the advantages of the original topology, higher efficiency and less stress on switches are achieved under light load.