Application Of Hybrid Energy Storage System In The Fast Charging Station Of EVs

As the next generation of automobile, electric vehicle(EV) has the advantage of reducing fuel consumption and greenhouse emissions. Recharge infrastructure is essential for development of EVs. Fast charging is a significant recharge method which provides a solution to extend driving range of EVs, and it will be popularized in the near future. But the impact of large scale of fast charging load on power system should be considered. Supported by the national 863 program, this thesis carries out a reseach on the impact of fast charging of EVs on power grid and the mearsures of eliminating this impact.Three parts are included in this thesis. Firstly, static voltage stability and frequency stability of power grid with fast charing load are analyzed. The analysis result is the basis for the application of energy storage. Secondly, two indexs to make fast charing load controllable is presented, and the application of hybrid energy storage system(HESS) in the fast charging station is proposed. The coordinated controller of HESS is designed in this part. Finally, technical-economical analysis of the fast charging station with HESS is conducted. This analysis solves the optimal allocation problem of HESS. In this analysis, control strategy of HESS and randomness of fast charging behavior is considered.The innovation of this thesis is the proposal of a new application of HESS which eliminates the impact of fast charging load. Among different kinds of high power density energy storage, the promising superconducting magnetic energy storage is selected as an energy storage unit of HESS. The coordinated control strategy which guarantees stable, reliable and economic operation of HESS is highlighted. Moreover, optimal allocation method which minimizes the comprehensive cost is introduced, and it will lay the foundation for practical application of HESS in fast charging station.