Abstract: The main winding square-wave current strategy, the least magnetomotive force strategy and the average radial force strategy used for bearingless switched reluctance motors (BSRMs) are introduced, respectively. And the methods of calculating the advanced angle and winding current with the suspended force equation and the torque equation are analyzed under these control strategies. Due to differences of control objectives and constraints introduced by the three control strategies, even when the motor has the same load, the advanced angle, main winding current and suspended winding current obtained by calculation are dissimilar. Then the dynamic magnetic flux density of the iron cores is attained by the transient finite element method, and the magnetic field characteristics of BSRM are studied under different control strategies. Finally, eddy current losses and hysteresis losses are separated from iron losses of BSRM using the double frequency method with each of the three control strategies, respectively. Thus, the effect of different control strategies on iron losses for BSRM are investigated.

Key words: bearingless switched reluctance motor, control strategy, iron losses, eddy current losses, hysteresis losses, finite element method