Stability Test Analysis and Design of High-load Magnetic Bearing Assembly for The Rotor of Flywheel Energy Storage System

As the core component of FESS(Flywheel Energy Storage System), the performance of magnetic levitation bearing directly affects the stability of high-speed rotor and the power consumption of the whole system. This paper aims at the engineering product development of 300KW/1.25KWh FESS. Combining with the decomposition of performance index of FESS, the design idea of flywheel rotor-ontology with metal wheel hub and composite wheel rim was put forward. Aiming at the demand of high reliability of magnetic bearing assembly for high speed rotor of high power of FESS, based on the comprehensive consideration of the relationship between the structure size, displacement and force, displacement and stiffness, current and force of the magnetic guide, the permanent magnet bias hybrid magnetic bearing assembly was designed. For the maximum bearing capacity of magnetic bearing assembly as the design goal, the driving control method that based on the 5-DOF(Degree of Freedom) of magnetic bearing of CDFC(Cross Decoupling Feedback Control) is studied and the power loss of magnetic bearing is effectively reduced. Finally, through the high-speed test and steady-state running-in test of the whole FESS, the stability characteristics of high-speed rotor under the condition of multiple speed change are analyzed and verified, which provides technical support for the practical application of flywheel energy storage system.