Strategy Optimization Of Electric Vehicle Aggregator Coordinated Charging In Residential Community

As the problems of global energy security and environmental pollution becoming increasingly serious, the advantages of zero (low) emissions, high performance and independent of fossil energy of electrical vehicles (EVs) have attracted the attention of governments and industrial field extensively. And the promotion and application of EVs are regarded as a significant breakthrough point for the problems of energy and environment. However, given the randomness of EVs charging in time and space, the safety of power distribution networks can be affected greatly when large-scale EVs connected to them. Therefore, it is of great theoretical and practical significance to study the coordinated charging of EVs.This paper studied the access and control mode of AC charging piles of residential quarter and proposed an energy requirement-oriented coordinated charging strategy. The concrete research contents are as follows:(1) Considering the aspects of power battery charging features, charging quantity and EV connection time, the EV charging load model was established. The EV charging behavior was simulated by Monte Carlo method, and taking the power distribution network load of a residential community for example, the EV uncoordinated charging behavior was simulated. The simulation results shown that the disordered charging of EVs could add peak to the load peak of the power distribution network, aggravate the load curve fluctuation, which is bad for the steady and economical operation of the power grid.(2) The EV aggregator charging system was divided into device layer, control layer, scheduling layer and platform layer by accessing control mode. The paper proposed the energy requirement-oriented coordinated charging strategy of EVs, which determined the target charging loads by the total energy requirement of EVs in the community, distributed the required energy of EVs on time scale and made the total load curve stay steady. The simulation results show that the coordinated charging strategy can effectively disperse electric vehicle loads, reduce users charging cost and the fluctuation of the daily load curve.(3) In the situation of the real-time load of the community is difficult to obtain, the coordinated charging control of EVs was achieved based on simulated load curve which was generated by the time-of-use (TOU) price and transformer capacity.Trapezoidal charging function was introduced to avoid the load spike at the time of peak-valley conversion, optimizes the control result, make it of higher feasibility and practicability. The results show that the introduction of trapezoidal coordinated charging function can meet the demand of the EV users well, reduce the peak-valley differences and decrease the load fluctuation greatly in the situation of simulated based load; The optimized control strategy can run stably for a long time, which is suitable for the large-scale EVs coordinated charging control online.