Research On Charging Demand And Charging System Operation Efficiency Of Electric Vehicle

With the rapid development of global economy and the continuous improvement of industrialization level,fossil energy is consumed in large quantities,resulting in the increasingly serious problem of global warming caused by greenhouse gas emissions.New energy technology has become an effective solution to the current energy shortage and climate warming.New energy vehicles(NEVs)are the application of new energy technology in the field of transportation.Whether in solving the energy crisis,global warming or the field of automatic driving in the future,NEVs will be an ideal solution.At present,countries all over the world are vigorously developing the NEVs industry,and the scale of NEVs is increasingly growing.With the large-scale electric vehicles(EVs)connected to the power grid,it will also increase the volatility of the power grid and bring a series of unsafe factors to the power grid.Therefore,the research on the temporal and spatial distribution of EVs charging demand(load)and the efficiency of charging system is of great practical significance to promote the development of NEVs industry.Around the above problems,the main work of this thesis is as follows:This thesis investigates the spatiotemporal distribution of charging demand for urban EVs and the operation efficiency of the charging system.Based on the 2017 National Household Travel Survey(2017 NHTS)data,the probability distribution model of the spatial and temporal characteristics of the trip chain is extracted for the simulation of travelers’ daily travel activities.Based on the utility function,the rational person assumption and the heterogeneity of individual preferences of travelers are considered,and the charging decision model is constructed.According to the characteristics of the research problem,the space-time distribution analysis framework of charging demand is constructed by multi agent system(MAS),and the difference of charging demand under different charging pricing strategies is analyzed.Finally,for each participant in the charging system,the indexes of three dimension,namely,the rejection rate of charging requests,the utilization rate of charging facilities and the fluctuation rate of charging load are set up.The influence of the number of charging facilities in different functional areas on the operation efficiency of the charging system is studied,and the effectiveness and expandability of the prediction algorithm for the spatio-temporal distribution of charging demand are verified.The case analysis results show that the time-of-use pricing strategy has certain limitations in achieving the effect of peak shaving and valley filling,and household charging is the charging method that travelers mainly rely on.The research results of the operation efficiency of the charging system show that there is a transfer relationship for charging demands between different functional areas,which makes the charging facility operators have more flexibility and selections when deploying charging facilities in different functional areas.At the same time,the travelers’ demand for charging facilities in workplace is relatively low.Therefore,solving the construction planning and operation problems of charging facilities in residential areas is of great significance to improve the operation efficiency of the charging system.