Distributed Energy Resources Based EV Charging Station With Seamless Connection to Grid

Abstract

The charging of electric vehicles (EVs) via common DC bus charging infrastructure based on hybrid renewable energy sources such as solar photovoltaic (PV) and fuel cell is presented here. The requisite to incorporate renewable energy based distributed energy resources (DERs) is attributed to the escalating concern for decarbonisation with improved power quality requirements. Furthermore, the bidirectional flow of power enables the charging/discharging of EVs during the grid presence/absence modes of operation. In addition, the utilization of common DC bus charging mechanism for EVs, facilitates fast charging capability at higher voltage levels. The satisfactory operation during the grid availability/unavailability is attained through the current and voltage based control mechanisms, along with the seamless transition capability via switching (STS-1/0) of the static transfer switches. Furthermore, in compliance with the IEEE standards, the power quality (PQ) improvement is obtained with the utilization of an adaptive comb-filter based current control during the grid-tied mode of operation. The need for improving PQ, stems from the fact that an uninterrupted supply is essential to the critical loads along with an improved power quality. Thus, for validation and corroboration of the system behavior, its performance is authenticated during weak grid conditions, in conjunction with grid connected/islanded modes of operation.