Study of Coordination Control Method of Multi-Port Solid-State Transformer Against Power Fluctuations

The multi-port solid-state transformer (SST) stands as a highly promising power electronic apparatus, providing favorable interfaces for energy storage, distributed generation, and loads. Given its essential role, a coordination scheme to ensure its bus voltage stabilization is critical for its operation. In this paper, the design of a multi-port SST's topology structure is put forward, elaborating its mathematical model and control framework of each stage. Then, a coordination control methodology tailored for the multi-port SST is proposed. Analyzing the inherent characteristics of each port as well as the energy flux among different ports, the operation modes of the multi-port SST are established in alignment with bus voltage fluctuations and the state of charge (SOC) of the battery energy storage system (BESS) and superconducting magnetic energy storage (SMES) in the hybrid energy storage system (HESS). Fuzzy control is adeptly employed to attain reasonable power regulation between BESS and SMES. Ultimately, the cogency and viability of the proposed strategy are validated through a simulation study conducted on the Simulink platform.