Repulsive Magnetic Bearing Stabilized by the Motion Control of Permanent Magnets for Suspension

A magnetic bearing system using forces of repulsion between permanent magnets is developed. In the developed magnetic bearing, radial motions of the rotor are passively supported by repulsive forces. For supporting the axial motion of the rotor, active control is necessary because of inherent instability in this direction. Stabilization is achieved by using the motion control of the permanent magnets for passive radial suspension; these magnets are driven by voice coil motors in the axial direction. The characteristics of the system are studied both theoretically and experimentally.