Abstract
Recently, smal1-sized rotating machinery such as turbomachines and flywheels are required to be driven at high rotational speeds and to maintain a clear environment. Active magnetic bearings can meet these requirements. The magnetic bearing system described here has been developed for high-speed rotating machinery. The model is a 4-axis-active type with a simple structure. Since the model is the so-cal1ed outer-rotor type, the resonance frequency of the rotor could be set higher than the rotating frequency, and only first-bending-mode frequency of the stator shaft is in the rotating region. In the high-frequency region, as the characteristics of the power amplifier become worse and the stability of the gyroscopic motion (nutation and precession) decreases, control of the flexible mode without adverse influence on another mode is very difficult. In this paper, a suppression method using stator's acceleration signal obtained from an observer circuit is discussed and compared to a conventional notch filter one.
