Influence of the Rotational Stability by Adding Weight to the Rotor in the HTS Magnetic Bearing System

Magnetic bearings in flywheel energy storage systems support the flywheel without physical contact through magnetic force, thereby mitigating friction, noise, and energy loss during rotation. In this study, a high-temperature superconductor (HTS) magnetic bearing is employed. The HTS magnetic bearing system consists of an HTS on the stator side and a rotor comprising permanent magnets, yoke, aluminum, and magnetic shields. The rotor is passively and stably levitated by the pinning effect which results from the interaction between the magnetic flux of the permanent magnets and the HTS. This paper investigates the influence of the rotational stability by adding weight to the rotor in the HTS magnetic bearing. Results show that radial displacement, angular displacement, and rotational attenuation are suppressed when weight is added to the rotor. That is because the inertia force was increased by an increase in the moment of inertia of the rotor. Furthermore, stable levitation of the rotor due to the pinning effect was achieved regardless of rotor mass.