Comparison of AMB-rotor system using multiple phase-shift notch filters connected in series and parallel modes for vibration control

Undesired vibration force caused by harmonic current is a common problem in an active magnetic bearing(AMB)-rotor system. It poses a potential threat to system stability and performance degradation. In this work, phase-shift notch filter is adopted to maintain the system stability in the varying speed range. The scheme of AMB control system with multiple notch filters connected in series mode is proposed for harmonic current suppression. By performance comparison, the analyses show that there is almost no difference between series-mode and parallel-mode notch filters in terms of suppression effect. But parallel-mode notch filters provide a more efficient way of digital implementation. Simulation and experimental results for system stability and vibration control on a magnetically suspended flywheel validate the comparison conclusions.