SMES-Battery Hybrid Energy Storage System Integrated Railway Power Conditioner for Peak Load Shifting and Power Quality Improvement in High-Speed Electrical Railway

In order to decrease the fluctuation of pulse power and improve the power quality in high-speed electrical railway, superconducting magnetic energy storage (SMES) in conjunction with battery as a hybrid energy storage system (HESS) integrated railway power conditioner (RPC) is proposed in this paper. The HESS is integrated into dc-link of RPC via interface circuit. An energy management strategy based on traction load power to control HESS charging and discharging is proposed. The scheme of power sharing is presented in which the battery is used to suppress the low frequency power fluctuation, whereas the SMES is used to suppress the high frequency power fluctuation. The control strategy of each converter is expounded in detail, respectively. The results reveal that the fluctuated power in high-speed railway system is smoothed and the power quality is improved by the proposed topology and control strategy.