A novel concept of a single-drive bearingless motor

A bearingless motor can be driven without any mechanical contact, thus, it offers the advantages of high mechanical durability, no material wear, and high speed drive. To realize non-contact suspension, a rotor should be magnetically stabilized in five (three-translational and two-tilting) degrees of freedom (DOF). Various types of bearingless motors with active regulation of two- to five-DOF have been developed. However, an increase in the number of actively controlled DOF causes an increase in size, volume, cost, power consumption, and complexity of the system. In this paper, a novel concept of the one-DOF controlled bearingless motor, hereafter referred as a single-drive bearingless motor, has been proposed for the downsizing, energy saving, and cost reduction. The single-drive bearingless motor requires neither additional windings nor inverters with respect to the conventional motor and driver. To verify the novel concept, the finite element analysis and experiments are carried out. The test results have demonstrated the realization and the feasibility of the novel proposed single-drive bearingless motor.