A Multi-mode Operating Tri Port Based Electric Vehicle Charging Station

Abstract

This study aims at improving the continuity of power supply for electric vehicle charging service by operating the Charging Station (CS) in either grid connected mode, islanded mode or diesel generator (DG) set connected mode. This is achieved by the connection of power grid, Solar Photovoltaic (SPV) array, DG set and battery energy storage (BES) to an EV charging station. Primarily the charging station is designed to utilize the solar photovoltaic PV array and to make use of BES for charging the electric vehicle (EV) battery. The second priority is to charge the EV battery by the power from grid and the last option is the use of DG for the same purpose. The DG or charging from grid option is opted under the case that there is no power extracted by SPV and the BES is depleted. However, the load is maintained at 80-85% in order attain the peak fuel efficiency under all the load conditions, when the power is extracted from the DG set. In combination of battery storage, the control of voltage and frequency is achieved by the charging station. This coordination certifies that the power that is drawn from the grid or DG set is at unity power factor even when the loads are non-linear. The synchronization is done at the point of common coupling voltage to the generator/ grid voltage to obtain interruption less charging. The active/ reactive power transfer of vehicle to grid, vehicle to home and then vehicle to vehicle is done by the charging station for the reason to increase operational efficiency. This paper uses the fuzzy control technique to enhance smooth operation of the charging station, the results ae obtained through the use of MATLAB/Simulink software.