Research On Key Techniques Of EV Charging Station With Flywheel Energy Storage System

As an important infrastructure, electric vehicle (EV) charging stations play an important role on the popularization and promotion of EVs. In order to regulate electrical energy of the peak and valley and decrease electric power waste of grid, it is necessary to increase power storage system in EV charging station. There are almost no the related researches about the above theme both at home and abroad. In this paper, based on idea of EV charging station with distributed flywheel energy storage system, through increasing power storage system in the traditional EV charging station, the author carry on a thorough research on key techniques of EV charging station with flywheel energy storage system, such as the basic structure, composition principle, etc.The main work contents and achievements of this paper are as follows:1,According to the overall layout and structural characteristic of EV charging station with flywheel energy storage system, the characteristics of four subsystems including the charging, the power storage, the distribution and the auxiliary power using subsystem are researched. Depending on the relevant standards and technical specifications,the overall project and subsystem of EV charging station with flywheel energy storage system are designed.2,Three kinds of operating modes of EV charging station with flywheel energy storage system are analyzed. The work flowcharts in different modes are established, and their electric quantity equations are determined. After considering the power dissipation of every subsystem, the mathematical model of charging processes in EV charging station are obtained. Taking the Class I EV charging station which defined in the Beijing standard as example, through simulating and calculating, the optimal allocation between the power supply capacity and the power storage capacity is gotten.3,According to the operation requirements of the flywheel energy storage system, permanent magnet synchronous motor (PMSM) is selected as a motor of flywheel battery, then the control of flywheel system will be simplified to the control of motor speed in PMSM. Based on the mathematical model of PMSM, after using double-closed-loop PI control of current and speed, the whole control model of the flywheel energy storage system is establish in MATLAB/Simulink. Through simulating, the feasibility and effectiveness of the control scheme is proved.4,The basic requirement, the operation mode and basic structure of charger are analyzed. The equivalent model of charger is established on the basis of structure diagram of high-frequency charger. Then simulation model of the charger is established in MATLAB/Simulink, then overall simulation model of EV charging station is built.