高频变压器并联耦合型电动汽车快速充电接口

Fast Charging Port of Electric Vehicles Based on Parallel-connected High Frequency Transformer Coupling

针对传统直流充电接口功率等级低、电流强度大、损耗高的问题,提出一种新型多高频变压器并联耦合的电动汽车快速充电直流变换拓扑结构,采用并联模块化设计,整体提高了电动汽车的充电容量。并联结构往往无法实现各模块电流平衡,为解决并联变压器间电流不平衡问题,设计磁耦合电流平衡单元(MC-CB),通过硬件实现模块间电流均衡。详细分析了充电接口的工作原理,论述了MC-CB的特性及设计方法。最后搭建了一套输入电压为760 V,输出电压为200~500 V,输出功率为20 kW的实验样机,实验结果验证了该结构的正确性与优越性。

The multi-parallel-connected high frequency transformer employed in the fast charging DC port in the charging station of electric vehicles is proposed to deal with the limitation of low power level, high current stress and loss for the conventional DC port.In order to suppress the unbalancing current from the parallel-connected transform- ers,using a magnetic-coupling current-balancing cell（MC-CB） to achieve the current-sharing by open-loop eontrol.A brief discussion of the general operating principle of the DC charging port system is given.Therewith, the structure and feature of the MC-CB is introduced in detail.Finally,a 20 kW experimental prototype which interfaces a 760 V DC bus with the output voltage ranges from 200 V to 500 V is built and tested.Experimental results are given to prove the validity and superiority of the proposed converter.