Axial Vibration Characteristic of Levitation Force for Radial-Type Superconducting Magnetic Bearing

Dynamic levitation behavior is crucial to the stable operation of superconducting magnetic bearing (SMB). In this article, we mainly focus on the axial vibration characteristic of levitation force for the radial-type SMB. The axial levitation force is calculated by using the H-formulation two-dimensional (2-D) axial-symmetry finite element model established in COMSOL. Also, experimental measurements of the levitation force are carried out under the field-cooling and zero-field cooling conditions. The comparisons show a good agreement and validate the modeling method. Based on the model, the dynamic levitation behaviors of radial-type SMB are investigated when the permanent magnet (PM) rotor vibrates axially. The influences of different axial vibration amplitude and period on the levitation behavior are mainly concerned and validated by experimental measurements. It is concluded that the levitation force will vary as a rule similar to the position variation of the PM rotor and the overall attenuation trend is similar to the trend of relaxation for the levitation force. Besides, the degree of attenuation increases obviously and is related to the vibration period and amplitude. The obtained results may be useful to the study of dynamic levitation behavior and the engineering applications of SMB.