System-level charging control strategy for plug-in electric vehicles

Charging control strategies can significantly alleviate the impact of electric vehicles (EVs) to power systems, as well as utilize the flexibility of EV charging to achieve extra benefits. This paper proposes an EV charging control strategy to achieve valley-filling using EV charging load. The strategy consists of system-level control and supporting control for the charging of individual EVs. The system-level control generates the basic charging command on total charging power, and the supporting control criteria manage the charging of individual EVs considering their arriving and departure dynamics. This paper shows that the charging control of EVs can be extremely simple to achieve similar performance comparing to existing methods, by utilizing the features of EV activities and power systems. The computational burden of the proposed strategy is incredibly low, and it is more feasible for practical application because of the simplicity and the lower implementation cost. Simulation results are demonstrated to support the feasibility and effectiveness of the proposed strategy.