Optimal Suspension Winding Configuration in a Homo-Polar Bearingless Motor

The authors have proposed a six-pole homo-polar type bearingless motor intended for a use as a small power and ultra high-speed motor. In a six-pole homo-polar rotor, crucial suspension force interference is caused. Thus, the suspension winding configuration should be carefully designed. In this paper, theoretical calculation is carried out with several structures to find the optimal winding configuration for reduction of the force interference. To verify the theory, finite-element-method (FEM) analysis is carried out. A test machine is also fabricated. FEM analysis and experimental result have demonstrated that the proposed optimal winding configuration can successfully reduce the force interference.