Control of 6 Degrees of Freedom Salient Axial-Gap Self-Bearing Motor

This paper introduces the control of a 6 degree of freedom (DOF) axial-gap selfbearing motor (AGBM), in which a hybrid active magnetic bearing system is in charge of 4 DOFs for radial levitation in x and y directions, and a salient type permanent magnet AGBM takes charge of 2 DOFs for rotation and axial motion in z direction. First, structure and working principle of the hybrid magnetic bearing and the AGBM are analyzed. The radial force equations of the hybrid magnetic bearing, and the electromagnetic torque equation as well as the axial force equation of the AGBM are then given. Finally,control structure is derived to confirm that the complete non-contact levitation can be realized by the simple construction and control system. To demonstrate the proposed technique, a salient 2-pole AGBM has been constructed and tested. The experimental results confirm that the AGBM drive performs well when its rotor is completely levitated.