Advanced design and experiment of a small-sized flywheel energy storage system using a high-temperature superconductor bearing

Abstract

A small-sized flywheel energy storage system has been developed using a high-temperature superconductor bearing. In our previous paper, a small-sized flywheel was fabricated and successfully rotated at 38 000 rpm under a vacuum condition. However, a large drag torque was present because of the non-axisymmetric magnetic flux of the motor/bearing magnet and the eddy current loss in the planar stator, resulting in a short spin-down time of 20–30 s and a coefficient of friction of 0.15.