The Study On The Control Strategy Of V2G Participating Peak Regulation And Frequency Regulation Of The Grid

With the development of the electric vehicles (EVs) technology and the battery technology, as well as pressing for the energy storing device, there are increasing people who begin to pay attention to the research of the technology of Vehicle-to-Grid. Vehicle-to-Grid technology is a new type of technology that can accomplish the bidirectional exchange of the communication and the energy with controlled, bidirectional chargers. It emphasize that allowing an EVs charge the battery as well as deliver power back to the grid from the EVs' battery.V2G system concentrate power electronics, communications, dispatch and metering, load demand management and many other advanced technologies in one integrated application system, which express EVs'function of energy storing. With the large scale development and application of the Electric vehicles, controlling the charge and discharge of vehicles reasonably can serve the peak power and fill the valley, reduce the reverse capacity for peak load regulation and frequency regulation in the traditional grid, as well as contribute the grid to absorb amount of renewable energy, all which improve the effectiveness, stabilization and economic efficiency.With the rapid increase of the load, the difference between peak power and valley is increasing year by year. So there is increasing large express from load power regulation. What is worse, the develop strategy of exploitation of renewable energy that make the peak power regulation more difficult. V2G technology gives a new method for the peak load regulation and frequency regulation in the future grid.In the paper, the concept of the V2G is introduced at first, and then an idea that distributed connection and concentrated control for the amount of vehicles is presented. But making the operator communicate to every vehicle and send a power dispatch command is unreasonable. For which an electric vehicles control center is used to manage and control all the distributed vehicles, and to be a certain controllable energy storage unit to communicate to the operator. Based on this business model, a hierarchy control method is presented, which consist of the patch control layer and the EVs control center layer.In the paper, at the base of analysis about of the feasibility and the advantage of EVs serving peak load regulation and frequency regulation, the control strategy is studied especially. In the paper, the mathematical model of vehicles participating load responses and accomplishing a dispatch scheme are established, and solve it by the Particle Swarm Optimization, in which constricts of available capacity of the battery, available time and exchange power are considered. Aimed at solving PSO's premature convergence for high-dimensional problem, the paper advanced an improved PSO based on sub-vector, it can be sure for searching for the far better position from the whole space, while divide the search space into several low-dimensional and small space to avoid premature convergence. Finally, an example was given to verify that electric vehicles controlled reasonably could contribute to the load responses. The improved PSO is more effective for high-dimensional problems by comparing with PSO. To the frequency regulation function of EVs, the control strategy is presented from serving the primary frequency regulation and the secondary regulation.To encourage vehicle users participating in V2Gactively, there should be a certainprofit margins for the users, and power system can make a reasonable price mechanism or some other compensation methods to attract users.