A trial manufacturing of 0.2kWh class flywheel rotor supported by superconducting magnetic bearing for energy storage system

Abstract

A flywheel rotor whose a main shaft had two pieces of flywheel disk and one magnet was designed and manufactured. The flywheel was made of CFRP material which is light weight and has high tensile strength. The magnet was hooped by CFRP in order to prevent from centrifugal burst. The rotor was suspended by a superconducting magnetic bearing in axial direction and active magnetic bearings in radial direction. The superconducting magnetic bearing was made of Y Ba₂Cu₃O_7-x which had a strong pinning force. It was stably accelerated up to 16, 500rpm by a induction motor in a vacuum chamber and then its energy storage value was 176Wh. The rotor design, bearing and rotational properties of the rotor was discussed.