The Study On The Flywheel Energy Storage System With Superconducting Bearing

Flywheel energy storage (FES) is a superior type of late-model energy storage technology. At present, FES technology already in domains and so in many fields such as uninterruptible power supply (UPS) systems, electrical power systems, hybrid electric vehicles has obtained the successful application.Flywheel energy storage system (FESS) is composed of four parts: the flywheel that stores energy, the bearing that supports the flywheel, the DC motor/generator and the control system of AC power converter. Due to the friction existing in mechanical bearing, it is difficult to store energy effectively for a long time, but it is easy for a flywheel levitated by superconducting magnetic bearing.As the basic study of superconducting flywheel energy storage system, this thesis is mainly engaged in researches on-flywheel rotor and high temperature superconducting (HTS) magnetic bearing, the key components in FESS, establishes the foundation for the further research.In the first pat of this thesis, the numerical and analytical studies for flywheel rotor have been made, and that optimal designs for rotor's configuration and material parameter have been done. With the assumption of the plane stress (PSS),this part makes the theoretical analysis for single-ring flywheel rotor, and has drawn the flywheel's radial and hoop stress in radial location. In order to reduce the production costs, enhance the stored energy and the material use factor, configuration of flywheel rotor has been optimized with the object of maximizing its stored energy. As a result, for the single-ring flywheel rotor, its optimal inner radius and outer radius have been found.In the second part of this paper, the principle of high temperature superconducting magnetic bearing has been carried on first. Then the hysteresis of levitation force curve have bean studied with the aid of Bean model. And in this paper, further analysis for the effect of the size and the thickness of a HTS on the levitation force and the properties of bearing have been done.Finally, the electrical part and mechanical part of the entire FESS have been given for the reference of the latter design.