Magnetic bearing using displacement winding techniques

Abstract

The present invention provides a linear, rotary spherical motor with an integrated magnetic bearing. The motor can be a toothless permanent magnet, BLDC design composed of a permanent magnet rotor and a Zigzag stator winding containing at least two-phase windings, where each phase is constructed of at least two circuits. Other exemplary embodiments include a trapezoidal winding configuration. The individual circuits of a phase are displaced away from each other along a line that is at right angles to the direction of the alternating polarity magnet array. The circuits forming a phase share the same 'slot', and each circuit resembles a complete phase winding, however each circuit contains a proportion of the total number of turns of the phase. Controllable axial bearing force is developed through the differential balance of the currents in the circuits, while required motor torque is generated by the sum of the individual currents in a given phase. The relative motion in the rotor can produce back EMF which can provide positional information; A) in the direction parallel to the magnet array via the sum of the voltages in a phase; B) in the direction normal to the magnet array via the difference in circuit voltages.