A model predictive control framework with fatigue life assessment for flywheel energy storage systems supported by active magnetic bearings

Flywheel Energy Storage Systems (FESS) represent a promising technology in modern power systems, particularly for renewable energy applications that demand long service life, high power density, and fast dynamic response. To enhance operational efficiency, FESS are typically designed with a flywheel rotor supported by active magnetic bearings (AMBs), which are well suited for high-speed rotating applications. In this study, a model predictive control framework is proposed to regulate the dynamic behavior of a FESS equipped with AMBs. The proposed MPC framework simultaneously controls the AMBs and manages the charging and discharging processes of the FESS through a Permanent Magnet Synchronous Machine (PMSM) operating as a motor-generator and mechanically coupled to the flywheel rotor. Numerical simulation results demonstrate that the proposed control framework effectively regulates the energy exchange process while maintaining stable rotor suspension via the AMBs. Furthermore, the dynamic performance of the FESS and its control system is evaluated in terms of fatigue loads acting on the flywheel rotor induced by repeated charging and discharging cycles, which significantly influence the overall service life of the system.