Affiliations: [a] Science and Technology on Inertial Laboratory,
Fundamental Science on Novel Inertial Instrument and Navigation System
Technology Laboratory, Beihang University, Beijing, China
Correspondence:
[*]
Corresponding author: Chun'e Wang, Science and Technology on
Inertial Laboratory, Fundamental Science on Novel Inertial Instrument and
Navigation System Technology Laboratory, Beihang University, Beijing 100191,
China. Tel.: +86 010 8233 9273; Fax: +86 010 8231 6813; E-mail: wangchune2008@163.com
Abstract: This paper deals with the novel structure and coupling analysis of a
3-degrees of freedom (3-DOF) conical magnetic bearing. The conical stators of
the bearing are designed symmetrical to provide the axial control exclusively,
and the radial stators are separated by nonmagnetic material between X and Y
channels, so the magnetic flux path can be separated among different channels.
The configuration and working principle of the bearing are provided, and the
mathematical model is derived based on the bias and control magnetic circuits.
In order to evaluate the degree of force coupling between different channels,
the concept of coupling factor is proposed, which is defined as the ratio of
force variation caused by coupling to the original force when there is no
coupling. The coupling factors are analyzed not only among the translational
movement of X, Y and Z channels but also between the translational and
rotational degrees of freedom. The calculation results show that although the
component coupling factors of each magnetic poles are a little larger, the
resultant ones in X, Y and Z directions of the designed bearing are all less
than 4%. Therefore, the magnetic forces and torques of different channels are
weakly coupled, and it is convenient for the control of the magnetic bearing.
Keywords: Conical magnetic bearing, magnetic force coupling, coupling factor, equivalent magnetic circuit
