A High-Power DC-DC Converter for Electric Vehicle Battery Charger

A DC-DC converter for high-power battery chargers with the power-capacity over 6.6-kW for electric vehicle (EV) is proposed in this paper. Due to a new architecture, the proposed converter achieves the reduction of conduction loss at the primary-side by as much as 50% and has many benefits such as reduced circulating current, less duty-cycle loss, and lower secondary-voltage stress. In addition, its power handing capacity can be upsized easily with the usage of two full-bridge inverters and two transformers. Besides, all the active switches in the proposed converter achieve zero-voltage-switching (ZVS) during the 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 scale-downed 3.3-kW charger. The experimental results validate the theoretical analysis and show the effectiveness of the proposed converter as a battery charger.