Parallel mode notch filters for vibration control of magnetically suspended flywheel in the full speed range

Undesired vibration force caused by harmonic currents is a common problem in a magnetically suspended flywheel (MSFW) rotor system. It poses a potential threat to system stability and performance degradation. In this work, multiple different phase-shift notch filters are connected in parallel mode to suppress the vibration harmonics. First, the multi-frequency vibrations in the MSFW is modelled and analysed. Then multiple different notch filters in parallel mode are proposed to plug into the baseline magnetically suspension system. The performance comparison with the conventional multiple notch filters is investigated. The parameters design and calculation for the proposed method are analysed in details. Moreover, the closed-loop stability of the overall system is given in the full speed range. Finally, simulation and experimental results for the MSFW demonstrate the superiority of the proposed method on both harmonics suppression and stability preservation.