Research on hierarchical control algorithm for SMES-BESS hybrid energy storage system based on multilevel power allocation - Liu, Haiyang; Li, Jun; Wang, Pengfei; He, Baocan; Lu, Jing; Wu, Yanan; Tian, Yunxiang; Mao, Huafeng; Sun, Hanbin (Proceedings of SPIE, the international society for optical engineering, 2025)