Research On Frequency Modulation Mechanism And Control Strategy Of Electric Vehicle In Power Grid

Electric vehicle(ev)is the strategic direction of the global automotive industry in the future.It can reduce the operation cost,restrain the frequency fluctuation of the power grid and improve the system stability to participate in the auxiliary service of frequency modulation of the power grid by taking advantage of the two-load characteristics of electric vehicles.Therefore,under the premise of considering the characteristics of electric vehicles themselves and meeting the daily driving needs,it has become a new research hotspot to explore a reasonable and efficient frequency modulation control strategy for electric vehicles to participate in the power grid.Firstly,a frequency modulation model of the participating system using the hierarchical cluster network mode of electric vehicles is established.Based on Thevenin model analysis of power battery,SOC probability density of daily ev power battery is estimated according to normal distribution.Secondly,based on the modeling of frequency response characteristics and energy storage of electric vehicles,the simplified models of single region and double region are obtained.In this paper,several improved methods of traditional PSO algorithm are described,and the subvector-based improved PSO algorithm with the minimum mean square error of frequency curve as the objective function is obtained.The control strategy of the subvector-based improved PSO algorithm is proposed for single-region power system for Matlab/Simulink simulation.Finally,through the data of the 2016 electric vehicle network access demonstration project of the independent system trading operation institution of New York state in the United States,and through the comparison of multiple sets of simulation experiments,the frequency modulation system with the participation of electric vehicles is obtained,which can suppress the frequency fluctuation more effectively.Compared with the traditional method,the improved control strategy can quickly reduce the frequency fluctuation.In this paper,the control strategy of subvector improved PSO algorithm can play a role quickly and accurately when the system frequency fluctuates,providing a powerful tool for future large-scale electric vehicle network frequency modulation.