Levitation behaviours of an eccentric SC-PM system with multi-degree-of-freedom motion

The high temperature superconducting (HTS) magnetic levitation is actually a self-stable levitation with multi-degree-of-freedom (DoF). However, the research of HTS magnetic levitation focuses on the axial or radial levitation behaviour with single-DoF motion independently. This article mainly discusses the 3-D modelling and the levitation behaviours of an eccentric superconductor-permanent magnet (SC-PM) system with multi-DoF motion. Firstly, the Power-Law E − J relation is used to obtain the relationship of equivalent conductivity-electric field strength for the superconductor. Then, a 3-D finite element model (FEM) of SC-PM system is established and calculated in software MagNet. At the same time, the result of the simulation is verified by the experimental measurements. The axial levitation behaviour is analysed by establishing and solving the 3-D FEM in eccentric SC-PM system with different multi-DoF motions. The results show that the maximum axial levitation force decreases with the increase of the static eccentricity distance. When the PM rotor exhibits dynamic eccentricity, the axial levitation force presents periodic fluctuations of which the amplitude and period are related to the dynamic eccentric distance and speed.