Grid Connected Off-Board EV Charger with V2G / G2V and V2V Capability

This paper proposes an off-board charger for electric vehicles (EV) that can charge multiple EVs with grid power in “grid-to-vehicle” (G2V) mode and in “vehicle-to-vehicle” (V2V) mode. In addition, the proposed charger can feed power to the grid in “vehicle-to-grid” (V2G) mode. In the G2V and V2V combined modes, both grid power and another EV’s power are used simultaneously to charge another EV. By using this mode, the power fed from the grid can be reduced. A three-phase pulse width modulation (PWM) rectifier is used as the front-end converter that maintains a constant DC link voltage and unity power factor (UPF) at the grid side. In accordance with the IEEE 519 standard, the total harmonic distortion (THD) of grid current in V2G, G2V, and combined G2V and V2V modes is maintained at less than 5%. To maintain a constant charging and discharging current for EVs, a half-bridge bidirectional DC/DC converter is employed. The simulation of all four modes is validated using PSIM Professional.