A High-Power DC-DC Converter Topology for Battery Charging Applications

A DC-DC converter that can be applied for battery chargers with the power-capacity of over 7-kW for electric vehicles (EVs) is presented in this paper. Due to a new architecture, the proposed converter achieves a reduction of conduction losses at the primary side by as much as 50% and has many benefits such as much smaller circulating current, less duty-cycle loss, and lower secondary-voltage stress. In addition, its power handing capacity can be upsized easily with the use of two full-bridge inverters and two transformers. Besides, all the switches in the converter achieve zero-voltage switching (ZVS) during whole battery charging process, and the size of output filter can be significantly reduced. The circuit configuration, operation, and relevant analysis are presented, followed by the experiment on a prototype realized with a 7-kW charger. The experimental results validate the theoretical analysis and show the effectiveness of the proposed converter as battery charger.