The Investigation Of Operation And Control For EV Charging Stations With Photovoltaic Power

Electric vehicle (EV) and photovoltaic power generation are two importantdirections in the field of renewable energy. This thesis focuses on electric vehiclecharging station and photovoltaic power generation system, which includes energyallocation of electric vehicle charging station with photovoltaic power accessed,design of charging station distribution system, control strategy of dc micro-gridinterface converters and system operation mode.Firstly, this thesis summarized the research and the development status of EVcharging station, discussed the development of the EV charging station in our country,elaborated implications for research of EV charging stations with photovoltaic power,and then proposed the investigation of operation and control for EV charging stationswith photovoltaic power.Secondly, typical topologies of electric vehicle charging station are studied withreliability analysis method, and calculated both reliability and mean to failure oftypical topologies. Through comparison of typical topologies, taking account ofreliability, economics and access of photovoltaic power, a kind of ac and dctopologies of electric vehicle charging station with photovoltaic power is proposed,and analyzed the impact of power system and social and economic benefits of the EVcharging stations in the actual operation of the process.Thirdly, the dc micro-grid is composed of one dc/dc converter for photovoltaicarrays, one dc/dc converter for battery energy storage charging/discharging, onegrid-connected dc/ac converter and one dc/dc converter for battery power charging.The analysis and description of the principle of unit interface converter circuittopology and its control strategy. The simulations verify the feasibility and theeffectiveness of the proposed control strategies.Finally, analysis the principle of the control of EV charging station andsystem’s operating mode, the power balance of the system is taken into account inthis control strategy and combined with the actual operation. The dc bus voltage leveland system status are employed as an information carrier to distinguish differentmodes and determine mode switching.The dc micro-grid is available of eithergrid-connected operation or islanding operation. When dc micro-grid is available ofgrid-connected operation, an autonomous control method for modular dc/acconverters is proposed to realize smooth switching between constant voltage operation and maximum power point tracking operation, which enables the dc busvoltage regulation capability of modular dc/ac converters.Seamless switching of agrid-connected converter between rectification and inversion. When dc micro-grid isavailable of islanding operation, an autonomous control method for modular dc/dcconverters is proposed to realize smooth switching between constant voltageoperation and maximum power point tracking operation, which enables the dc busvoltage regulation capability of modular dc/dc converters.Seamless switching of abattery converter between charging and discharging. By using the proposed controlstrategy, the operations of dc micro-grid are categorized into four modes:grid-connected rectification, grid-connected inversion, islanding with batterydischarging and islanding with battery charging. The simulations verify thefeasibility and the effectiveness of the investigation of operation and contr ol for EVcharging stations with photovoltaic power.