Analyses of a bearingless machine with divided windings

The aim of this work is to show some characteristics of a bearingless induction three-phase motor using a vector mathematical model, for the control strategy. A 2D FEM model has been introduced in order to better understand the magnetic behavior of the device and to improve the control performances. The experimental device has been obtained starting from a conventional induction machine. The windings have been halved and the current in each half-phase winding is independently controlled to generate radial and rotational forces. The position control holds constant the total current in each phase whereas currents can assume distinct values in each half winding. The rotor displacement effect on the torque, on currents and on the device magnetic field distribution is discussed.