A G2V/V2G Off-Board Fast Charger for Charging of Lithium-ion Based Electric Vehicles

This paper proposes a bidirectional three phase off-board charging topology for charging of electric vehicles (EVs). The proposed off-board EV charger has innovative modes for the charging control of lithium-ion battery with respect to SOC. All these modes are switched on the basis of change in SOC. According to these modes, the reference charging current is adjusted. The proposed charging topology is composed of three phase AC-DC converter and a bidirectional DC-DC converter, which works as buck converter during G2V operation and it works as a boost converter during V2G operation. The AC-DC converter is controlled by comprehensive control technique. Compared to the traditional charging control technique, this topology controls the charging reference according to maximum charging acceptance characteristics of lithium-ion battery. The proposed charging control is validated by MATLAB/Simulink, operating through grid to vehicle including all charging control modes for lithium-ion battery and vehicle to grid control.