A 0.5 kWh flywheel energy storage system using a high-T/sub c/ superconducting magnetic bearing

Abstract

A flywheel rotor having a main shaft, two flywheel disks and one permanent magnet for a SMB (superconducting magnetic bearing) was designed and manufactured. The flywheel was made of CFRP material which is light weight and has high tensile strength. The permanent magnet was hooped by CPRP in order to prevent centrifugal bursting. The rotor was levitated by a SMB in the axial direction. The radial vibration of the rotor was damped by active magnetic bearings. The superconducting magnetic bearing was made of YBa/sub 2/Cu/sub 3/O/sub 7-X/ which had a strong pinning force. The whole rotor system was stably accelerated up to 30000 rpm by an induction motor in a vacuum chamber, and then its energy storage value reached 479 Wh. In this paper, the rotor design, bearing and rotational properties of the rotor are discussed.