Proposal and Analysis of a Novel Single-Drive Bearingless Motor

In this paper, a novel design of a one degree of freedom actively positioned bearingless motor, hereafter referred to as a single-drive bearingless motor, has been proposed. The concept is based on an axial flux motor where field weakening and strengthening with d-axis current modulation produce the suspension force for axial motion control. The single-drive bearingless motor requires neither additional windings, nor inverters for noncontact magnetic suspension. It has only one three-phase winding set and one three-phase inverter. To verify this novel concept, theoretical calculations, finite-element method analysis, and test machine development are carried out. The test results successfully demonstrate the magnetic suspension and noncontact rotation of the single-drive bearingless motor.