Research On The Control Strategy Of Electric Vehicles Participating In Frequency Regulation Based On The Mobility Demand

A large number of renewable wind and solar energy into the grid will cause the fluctuation of the grid frequency. Because of the operation capacity is lower, the traditional power grid gradually shows poor healing. However, electric vehicle(EV) battery is a big storage device, which can fast response the fluctuation of the grid frequency. EVs are regarded as one of the most promising way to suppress the fluctuation of the grid frequency and provide ancillary services.At present, lack of the reasonable and practical strategies of EVs participating in frequency regulation. It has not been well solved the problem between EV charging demand and frequency regulation. Therefore, this paper focus on the EV owners’ demand power calculation and scheduling EVs participated in frequency regulation. The research contents are as follows.1) Based on the analysis of EVs participating in frequency regulation on the basis of the structure and operational principle, the paper proposes a strategy that EVs participate in frequency regulation based on user demand, combined with users’ basic demand and the objective of EVs participating in frequency regulation. The strategy includes calculating user demand based on the EV owners’ travel distances and calculating and allocating the regulation capacity of EVs participating in frequency regulation.2) Based on the travel habits of EV owners, we study the calculation method of the power that EV users travel demand daily. According to the battery characteristics, vehicle performance and the user’s daily traveling distances, calculate the EV user’s expected battery level.3) This paper studies the optimization control strategy of EV battery whose power exceed EV owner’s expected SOC. The optimized scheduling strategy includes: 1) The optimization calculation of regulation capacity. By making the aggregator’s profits and tracking the frequency regulation signal as the optimization goal, establish the regulation capacity optimization calculation model,considering the EV battery’s available capacity and charging/discharging power conditions, ect. 2) Aggregator participates in the optimization allocation of the regulation capacity. By making minimizing the percentage of the changes of EV battery SOC in EV battery’s available capacity as the optimization target. The regulation capacity optimization allocation model was established, considering the users’ expected SOC, battery capacity and charging/discharge power, ect.Based on the above research work, this paper completes the simulation experiments of EVs participating in frequency regulation in power grid, based on user demand. We also compare it with the simulation results of existing method with the gaol of maximization benefits that EVs participate in frequency regulation. The simulation results show that the proposed method not only can track the frequency regulation signal more precisely, but also can meet user demand better and the users can get more benefits at the same time.