Research On The Key Technology Of Superconducting Magnetic Levitation Flywheel System

Flywheel system is a general type of actuator used for satellite attitude controland energy storage system, but a flywheel system with a conventional mechanicalbearing generally has the problem of large power consumption and short life time.Aiming at this issue, this paper studied the properties of flywheel system withsuperconducting magnetic bearing. A breakthrough design of superconductingmagnetic bearing was done concerning the the principle of superconductinglevitation, levitation force and properties of magnetic field, and the performance ofsystem has been evaluated thoroughly.Critical state model of the superonductor was established baesd on the study ofthe principle of the superconducting magnetic levitation. The levitation force ofsuperconducting bearing was simulated by ANSYS to analyse the the parameterssuch as thickness and radius, and the relationship between levitation force and thesize parameters of the superconducting bearing were determined. Further researcheswere done on the topics of combination form, cooling method, hysteresis effect andlevitation force relaxation by building a levitation force test agent, and the simulationresult of the force was vertified.In the final design of the superconducting magnetic bearing, planar brushlessDC motor was selected as the driving device. The flywheel rotor was integrated and vacuum system was designed within the restrictions of field-cooling height andmotor gap, so that the flywheel can operate stablely in the vacuum circumstance.The test of superconducting magnetic levitation flywheel system was conductedin a vacuum circumstance, and the highest rotational speed can reach up to33000r/min. Compared with a conventional mechanical bearing flywheel system,power consumption of the superconducting magnetic levitation flywheel system wasfound to be much less than that of an mechanical flywheel system. Studying on thespin-down curve at different cooling height and the influence of the field-coolingheight on the friction loss of superconducting magnetic bearing was analyzed fromboth the hysteretic loss and the eddy loss.