In this work a design is proposed for an active, permanent magnet based,self-propelled magnetic bearing i.e. levitating motor having the followingfeatures : (a) simple winding structure, (b) high load supporting capacity, (c)no eccentricity sensors, (d) stable confinement in all translationaldimensions, (e) stable confinement in all rotational dimensions and (f) highefficiency. This design uses an architecture consisting of a helically woundthree-phase stator, and a rotor with the magnets also arranged in a helicalmanner. Active control is used to excite the rotor at a torque angle lying inthe second quadrant. This torque angle is independent of the rotor's positioninside the stator cavity hence the control algorithm is similar to that of aconventional permanent magnet synchronous motor. It is motivated through aphysical argument that the bearing rotor develops a lift force proportional tothe output torque and that it remains stably confined in space. Theseassertions are then proved rigorously through a calculation of the magneticfields, forces and torques. The stiffness matrix of the system is presented anda discussion of stable and unstable operating regions is given.
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