Energy Storage Flywheel System with SMB and PMB and Its Performances

Since few years ago, electrical energy storage had attracted attention as an effective use of electricity and coping with the momentary voltage drop. Above all, the flywheel energy storages using superconductor have the advantages of long life, high energy density, and high efficiency. Our experimental machine uses the superconducting magnetic bearing (SMB) together with the permanent magnetic bearing (PMB) and plans to reduce the overall cost using the superconductor cost, and cooling cost. The purpose in this paper is to show the progress in the system performance by the improvement of PMB and the motor drive, and to estimate the system at that time of momentary voltage drop by making the discharge system.