Measurement Corrections for Active Magnetic Bearing Control

Rotor shaft position measurement is an important part of the algorithm performance in the active magnetic bearing control. The shaft centerline is estimated based on the measurement of the shaft surface distance to the sensor position. When the shaft surface has a large curvature, the measurement needs to be corrected in order to eliminate geometric correlations between measurements in the two axes. Such correlations have an impact on the control algorithm performance. The objective of this work is to propose a geometric model to estimate a more accurate position of the shaft centerline, considering also possible deviations of the sensor alignment. Corrections were applied to a control algorithm in an experimental active magnetic bearing workbench, showing an improvement of the control performance based on average distance to operation center criterion.