A Novel Cooperative Control for SMES/Battery Hybrid Energy Storage in PV Grid-Connected System

With the ever-growing integration of renewable energy sources (RESs) into the power grid to meet escalating power demand, the intermittent and volatile nature of these sources poses significant challenges to the stability of power grid. To address the unstable output power resulting from the inherent randomness and fluctuation of RES, this paper introduces a novel cooperative control strategy designed for a photovoltaic-based grid-connected system. This proposed strategy leverages both battery energy storage system (BESS) and superconducting magnetic energy storage (SMES) within the hybrid energy storage system (HESS) framework. At top-level control (TLC), the control strategy employs a fuzzy control-based low-pass filter (LPF) to dynamically regulate filtration coefficient and realize transient power allocation optimization. Simultaneously, at the underlayer level control (ULC), a fast Model Predictive Control (MPC) method is implemented to maintain DC bus voltage by one-step prediction horizon. The feasibility and superiority of the proposed control strategy are systematically validated under diverse operating conditions, demonstrating its efficacy in enhancing the stability and performance of the grid-connected system.