An attraction-type magnetic bearing with control in a single direction

This paper presents a new type of magnetic bearing with active control only in the axial direction. The bearing uses two pairs of permanent magnets working in attraction mode to restrict the radial motion and a control system composed of two electromagnets, a gap sensor, and a controller to keep the axis in a fixed axial position. The principle, the dynamic model for axial motion, and the control system for this bearing are presented. Finally, by experiments conducted on a prototype, the effectiveness of the concept here presented is shown.