Centralized Control Design for Bidirectional DC Charging Stations to Enable V2G

Abstract

In this study, a centralized primary control design is proposed for the DC charging station (DC-CS) to enable vehicle-to-grid (V2G) for electric vehicles (EVs). The proposed control design aggregates EVs with the optional energy storage system (ESS) in the charging station while balancing their state of charges (SoCs). Unlike the conventional methods, the proposed controller deploys EVs data including their energy capacities, SoC limits, and charging and discharging power limits to ensure the safe operation of EV batteries in the V2G mode. Additionally, it balances SoC significantly faster compared to conventional distributed controllers deploying a proposed centralized method to protect EV batteries from over-charge/over-discharge and extend the available total energy capacity in the charging station. The performance of the proposed controller is studied in a case study in the DC-CS.