Investigations on a new slotless homopolar hybrid active magnetic bearing

Homopolar hybrid active magnetic bearings generate very low power losses thanks to the absence of bias currents and the homopolar distribution of the magnetic ux density in the airgap. However, the slots in which the winding of these bearings are inserted create uctuations of the magnetic ux density which are at the origin of iron losses that can be non-negligible at high speeds. This paper investigates a new slotless topology of homopolar hybrid active magnetic bearings, which can totally remove these losses. An electromagnetic model based on a magnetic circuit is proposed and validated through finite element simulations. It is then used to optimize and compare the performances of this original bearing topology with an existing slotted hybrid homopolar bearing.