A Reconfigurable Single-Stage Three-Phase Electric Vehicle DC Fast Charger Compatible With Both 400V and 800V Automotive Battery Packs

A novel three-phase Electric Vehicle (EV) DC fast charger with a wide output voltage range is proposed in this paper. One of the main features of the proposed EV charger is that it can provide a wide output voltage range (i.e., 250 V to 850 V) using low voltage rating mainstream switches/diodes (i.e., 650 V). The proposed EV charger takes advantage of Inductor-Inductor-Capacitor (LLC) resonant tanks for each phase allowing soft-switching performance for all switches so the major power loss will be only conduction loss. Consequently, by operating at a high switching frequency the size of passive components can be reduced leading to a high-power density. Moreover, as the AC to DC conversion is being realized in an isolated single-stage approach, the total conversion efficiency for the proposed EV charger is higher than conventional two-stage EV chargers. The analysis of the power circuit design and control of the proposed EV fast charger is provided in the paper for both 400 V and 800 V automotive battery systems. Moreover, the performance is verified by computer simulation results and experimental results of a 1.5 kW laboratory prototype.