A new flywheel energy storage system using hybrid superconducting magnetic bearings

The high temperature superconductor (HTS) YBaCuO coupled with permanent magnets has been applied to construct the superconducting magnetic bearings (SMB) which can be utilized in some engineering fields such as the flywheel energy storage system (FESS). However, there are many problems needed to be resolved, such as low stiffness and damping, the uncertainty of working displacement, flux creep and flux flow. In this paper, a new FESS using hybrid SMB system which consists of SMB, active magnetic bearings (AMB), and permanent magnetic bearings (PMB) is presented. In this design, the authors constructed an experimental device for the FESS with hybrid SMB. An axial PMB is joined to provide a levitation force so as to suspend a heavier flywheel; in addition, two AMB are added in radial degrees to improve the stiffness by two orders of magnitude from 10/sup 4/ N/m to 10/sup 6/ N/m and the damping of FESS.