Ripple compensation of suspension force and torque in a bearingless SPM motor with integrated winding

This paper describes a simple ripple compensation method of suspension force and torque in a bearingless surface-mounted permanent magnet (SPM) motor with two-phase integrated winding configuration. Only two H-bridges or eight power transistors are used for the proposed topology. The neutral point of each phase is connected to the middle point of the power sources to superimpose the suspension and toque producing currents into the two-phase integrated winding. The theoretical suspension force and torque for 8-slot/2-pole PM motor structure are derived. The finite element method analysis has been performed to verify the proposed ripple compensation method, and the results shows that the proposed method significantly decreases the suspension force and torque ripples.