Investigation on the multi‐DoF 3‐D model and levitation behaviour of radial‐type superconducting magnetic bearing

Abstract

It is crucial to calculate the levitation force and model the levitation behaviour in the designation of superconducting magnetic bearing (SMB). At present, the related research focuses on the single degree of freedom (DoF) levitation behaviour of the SMB independently, for instance the axial or radial levitation force. Practically, the superconducting magnetic levitation is passive levitation at directions of multi-DoF. Additionally, the non-ideal conditions in fabrication, such as the joint effect of superconducting bulks, lead to complex 3-D-induced current distributions which generate the levitation force. There are coupling effects which affect the levitation forces at the directions of different DoFs. This paper investigates the multi-DoF modelling and levitation behaviour of the radial-type SMB. By adopting the Power-law E-J relation, the dependence of conductivity on electric field is derived to define the superconductive material. Then, the software MagNet is employed to establish the 3-D multi-DoF finite element model. Under the external disturbance of the PM rotor with axial constant speed and constant load, the multi-DoF levitation behaviours of radial-type SMB are discussed considering the joint effect of superconducting bulks. It is also obtained that the influence of the revolving speed, the static, and dynamic eccentricity on the axial levitation force.