Micro generator using flywheel energy storage system with high-temperature superconductor bearing

This paper presents the design and fabrication of the micro generator using flywheel energy storage system with high-temperature superconductor bearing. The micro generator is characterized by the three-phase axial flux permanent magnets. The planar stator is fabricated with 5-lines, 100 mum-width, and 50 mum-height for low eddy current loss and high current density. The flywheel rotates up to 51,000 rpm (3.4 [kHz] times 60 [sec]/4 [pairs of poles]) and stores the rotational kinetic energy of 337 J. The flywheel can rotate freely during 3 hr 20 min without input voltage and the coefficient of friction is calculated as 0.001~0.002. At maximum speed, the no-load three-phase electric output of the micro generator is 802 mV_rms.