EFFICIENT ELECTRIC VEHICLES INTEGRATION IN MICROGRID

Abstract

Electric vehicles integration to the conventional AC power grid system ensures the continuity of power supply under different circumstances. The conversion from AC-DC and DC-AC happens in G2V mode of operation and V2G mode of operation respectively. Buck and boost converters are for charging and discharging of electric vehicles. Power losses occurs across each converter and because of load variation of conventional AC power grid system, DC power system can overtake the AC power system. The AC power grid has many disadvantages but the primary disadvantage is the wide variation of load because of its operating frequency/duty cycle. This factor is not included in DC power system. The overall efficiency of the system improves and the system becomes more simple and controllable because numbers of converters are reduced. To maintain voltages on a DC bus bar according to the variation of load with the help of controllers (droop and PI controllers) will be simpler as compared to conventional AC power system. This work considers the possibility of creating an electric vehicles integration to the grid at parking lots of work places. The system is designed for the parking lots to charge EV’s as the mostly cars remain parked over there for a long time i.e. office time. The intention is to maximize the utilization of stowed energy of EV’s in V2G mode of operation and to maintain voltages according to the load variation. Power sharing from individual electric vehicle’s capacity is controlled by droop controller. The described technique is carried out using MATLAB to analyse the charging system characteristics and discharging. The results are analysed to ensure the feasibility of the proposed technique.