Optimization and realization of a multi-pole permanent magnetic bearing with rotating magnetization

Abstract

The focus of this paper is on optimizing the stiffness of a permanent magnetic single-ring bearing solely by changing the magnetization pattern. More precisely, using rotating magnetization with two magnetic poles rather than homogeneous magnetization results in a 3.7-fold improvement in stiffness. Usually, rotating magnetization is realized by Halbach stacking, that is, stacking several homogeneously magnetized rings with different directions of magnetization. The approach followed in this work realizes a continuously rotating magnetization pattern using only one ring. Optimization of the magnetization process, as presented in this paper, is crucial to achieving the maximum possible stiffness for the specified bearing dimensions. Furthermore, an analytical stiffness calculation method for bearings with arbitrary magnetization pattern is introduced, and the results are compared with finite-element calculations and measurements.