Fast EV charging station integration with grid ensuring optimal and quality power exchange

Abstract

Increased problem of air pollution has led automotive industry to develop clean and efficient fuel based transportation and Electric Vehicles (EVs) appear to be the most suitable alternatives to conventional IC engine based vehicles. Fast charging of EVs is required to make EVs widely accepted as charging time is the key barrier standing in the way of widespread acceptance of EVs. Different strategies have been proposed for the deployment and integration of public fast charging, emphasizing on the power quality aspects and charging load management techniques. This paper presents the model of a fast electric vehicle charging station connected to the grid ensuring quality power transfer with reduced harmonic currents. The charging station consists of a converter connecting grid to a DC bus where EVs get connected through battery chargers. The control of individual vehicle charging process is decentralized and a separate control is provided to deal with the power transfer from AC grid to the DC bus. An energy management strategy based on optimal power flow is also proposed by integrating a solar PV generation system with charging station to alleviate the impact of fast charging on the grid. The combined system along with the power output of EV fleet batteries available at the charging station reduces the net energy provided by the grid, thereby decreasing the overall load on the grid as well as minimizing the conversion losses. Keywords: Fast charging station, Electric vehicles (EVs), Power quality, Optimal power flow