A rule-based energy management scheme for uninterrupted electric vehicles charging at constant price using photovoltaic-grid system

Abstract

This work proposes a rule-based energy management scheme (REMS) for electric vehicle (EV) charging from photovoltaic-grid (PV-grid) system. The main feature of this scheme is that it provides uninterrupted daytime charging at a constant price. In order to simulate the system, the models of PV output power, EV power demand, state of charge (SOC) estimation of energy storage unit (ESU) and grid electricity prices are developed. The uninterrupted and constant price charging is achieved by managing the energy flow between PV, ESU and grid according to the rules defined by REMS. Furthermore, the valley-filling operation is implemented during the grid off-peak hours. The resiliency of REMS is validated under various weather conditions, different ESU prices and at grid parities. For comparison, its performance is benchmarked against the standard grid-based EV charging. The results demonstrate a decline in charging price by 16.1% besides reducing the burden on the grid by 93.7% with the implementation of REMS. In addition, the vehicle-to-grid (V2G) technology is incorporated in the charging system to improve the payback schedule of the existing PV-grid system.