Vibration attenuation control on HMBs

The article describes the study of the vibration control of unbalanced shafts supported by (active-passive) or hybrid magnetic bearings (HMBs). The vibration control study is carried out on the magnetic active part (stator) of a HMB on the basis of a diagnosis of the shaft dynamics. Since the mechanical faults affecting an active magnetic bearing has its origin in the machine rotor due to mechanical and/or magnetic disturbances, coils current is a reliable variable which can be measured and controlled simultaneously based on the electromagnets models and real time measurements. The vibration (amplitude, frequency and phase) is measured and a compensation current computed for amplitude and shifted phase is applied to attenuate the shaft vibration. Achieved results on a case study are compared with real-time vibration control results, being shown and discussed.