Coupled dynamics and control of a rotor-conical magnetic bearing system

Abstract

This paper is concerned with coupled dynamic characteristics of a conical magnetic bearing system and its influence on design of controllers. Conical electromagnetic bearings do not need additional magnetic poles to control axial motion of the rotor system and its particular structure leads to two coupled characteristics: geometry and current couplings. Because the coupled characteristics influence the design of a controller, they can not be neglected. This paper proposes the coupled dynamic characteristics of conical electromagnetic bearings for the first time and defines them. On the basis of the analysis of coupled dynamic characteristics, the dynamic model of a five-degree-of-freedom rotor-conical electromagnetic bearing system is made, and the influence of coupled characteristics on the optimal controller of the system is analyzed.

A conical passive magnetic bearing with constant stiffness

“…the bearing was not truly cone-shaped. A number of cone-shaped active magnetic bearings have been considered 13 , 18 , 20 , including complex structures with cone-shaped teeth 35 and bearing for use in magnetically suspended flywheels 9 , 34 . However, all of these works considers the dynamics of the active bearing and not the properties of a nested conical passive bearing.…”