Axial Position Control of a Lorentz-Force-Type Cylindrical Self-Bering Motor with Coreless Distributed Windings

A Lorentz-force-type self-bearing motor rotates and supports a rotor using the Lorentz force generated by the magnetic flux from the rotor’s permanent magnets and the current flowing in the stator windings. In the previous model, only rotational torque and radial forces were controlled by two coreless cylindrical six-phase distributed windings. This paper proposes a method to control the axial force using two diamond-shaped windings. The structure and control principle is introduced, then a prototype machine and the result of the levitation test are shown.