Analysis of self-sensing active magnetic bearings working on inductance measurement principle

Various methods have been proposed in the past to realize self-sensing or sensorless Active Magnetic Bearings (AMB's). In this paper, the inductance-sensing method is discussed, its basics are derived, and a test-signal injection method to implement this scheme is presented. In order to identify and quantize the limiting factors affecting the inductance measurement, a real AMB under working conditions is simulated using Finite Element Analysis (FEA) techniques. By doing so, conditions are brought out for the successful implementation of inductance-sensing schemes in AMB's. It is concluded that the scheme proposed saves complicated and costly hard/softwares for its implementation.