Vehicle-to-grid Control Strategy For Supplementary Frequency Regulation Considering Electricity Price

Due to the rising energy costs and electricity demand,electric vehicles(EVs)and new energy massively accessing into the power grid is the inevitable trend in the future.However,with the rapid growth of the emerging load and renewable energy,the traditional frequency modulation method of power system can not balance the load fluctuation and frequency oscillation caused by large-scale electric vehicles and intermittent new energy quickly and effectively.Though,as a kind of distributed energy storage unit,the electric vehicle has received extensive attention because of its excellent response characteristics.Therefore,it is very important to promote the electric vehicles' participation in the supplementary frequency modulation service for the improvement of the the power system's capacity in accommodating the new energy and load,besides the development of the new energy automobile industry.At present,the research on the frequency modulation of the electric vehicle has already begun,but the influence of the real-time electricity price on the frequency modulation of the electric vehicle has not been studied sufficiently.And this is the focus of this paper.The content is specifically divided into the following areas:Analyze the charging modes and scheduling modes of electric vehicles widely used in the world.Discuss the feasibility of electric vehicles to take part in the supplementary frequency modulation service from the aspects of quick response,battery capacity and connection time in the power grid.At the same time,analyze the economy problems in the frequency modulation price and the profits.Then elaborate the basic concept and principle of the three frequency regulation types.The two-area interconnected power system model with primary and secondary frequency modulation is constructed for simulation experiment.Next,put forward the V2 G structure framework of the primary and secondary frequency modulation service respectively.Considering real time electric price,analyzes the control principle and scheduling strategy of primary frequency modulation and secondary frequency modulation with electric vehicles,specifically including:1)Control the electric vehicles taking part in primary frequency regulation by frequencydroop characteristic.According to the real-time price information,the V2 G control center uses the participation factor to modify the droop gain K of the battery,then control the primary frequency modulation power of the single electric vehicle in real time.2)As the third party middleman,the electric vehicle aggregator is responsible for the communication between the power grid dispatching center and the electric vehicles.According to the real-time electricity price and expecting V2 G power issued by the dispatch center,utilize the participation factor to correct the frequency modulation task and then control the up/down V2 G power of the EV charging stations.Finally,With the assistance of MATLAB/Simulink,build the simulation platform of electric vehicle and analyze the simulation results,which show that the proposed control strategy can effectively reduce the frequency fluctuation of the system and meet the needs of the users' travel requirements and economic benefits.