Three phase off-board bi-directional charger for EV with V2G functionality

In this paper, a three phase off-board bi-directional charger is proposed for an electric vehicle (EV). The proposed charger exchanges the active power with utility and provides the reactive power compensation. The operating modes of bi-directional charger are: (i) an active power flow (charging and discharging), (ii) reactive power compensation (inductive and capacitive), (iii) simultaneous charging of EV and reactive power compensation, and (iv)discharging and reactive power compensation. The charger is also capable of operating under unbalance and distorted grid condition. The control of the charger uses the unit templates of point of common interconnection (PCI) voltages for generating the reference grid currents in synchronism with the PCI phase voltages. The harmonic distortion (THD) of the grid current remains within the limits of an IEEE 519 standard for all operating modes. The charger is designed for a 230V (rms) line-to-line (L2L), 50 Hz, three phase supply. The rating of the charger is selected of the order of 6.6 kVA. The performance of the charger is validated under various operating modes and at different dynamic conditions.