A Permanent Magnetic Bearing For The Hybrid Superconducting Magnetic Bearing System

摘要

High temperature superconducting magnetic bearings have several significant advantages over conventional magnetic bearings. However, the low stiffness, low dampness, the uncertainty of working displacement, and flux creep and flux flow make it impracticable to realize a flywheel energy storage system using superconducting magnetic bearings. In order to deal with these problems, a hybrid superconducting magnetic bearing system which consists of superconducting magnetic bearings, permanent magnetic bearings, and active magnetic bearings has been developed. In this design, an axial permanent magnetic bearing is applied to levitate the weight of the rotor, and initially position the rotor in the axial direction in order to reduce the need for initial loading systems. In this paper, forces and stiffness of the permanent magnetic bearing along three directions are evaluated both theoretically and experimentally. The hybrid superconducting magnetic bearing system can run safely at speeds up to 16,000 rpm with small vibration about 10 μm.