Vibration suppression for flywheel energy storage system using modal decoupling control

Magnetic bearings have been used in flywheel energy storage systems to improve their performance because these kinds of bearings can provide non-contact supporting so that the friction between the rotor and the bearings is reduced significantly. However, the gyroscopic coupling, parameter coupling, and imbalance force affect the operating performance and stability of a magnetic suspended flywheel energy storage system with asymmetric rotor; therefore, the main purpose of this study is to propose a control method for achieving decoupling and stable operation of the aforementioned system. To this end, after deriving the mathematical model of a radial 4-degree-of-freedom rotor–bearing system, a novel cross-feedback-based modal decoupling controller is designed for vibration suppression caused by gyroscopic coupling, parameter coupling, and imbalance force. Better performance is obtained through comparing the decoupling performance, control performance, and disturbance rejection performance with a traditional decentralized proportional–integral–derivative controller and a cross-feedback controller via ADAMS–MATLAB co-simulation technology and experimental results.