A Flywheel Energy Storage System with Active Magnetic Bearings

Abstract

A flywheel energy storage system (FESS) uses a high speed spinning mass (rotor) to store kinetic energy. The energy is input or output by a dual-direction motor/generator. To maintain it in a high efficiency, the flywheel works within a vacuum chamber. Active magnetic bearings (AMB) utilize magnetic force to support rotor's rotating shaft without mechanical friction. It also makes the rotor more dynamically controllable.A prototype of FESS with AMBs was developed. Dynamical model is obtained and analyzed for the rotor-bearing system. Control method is determined in accord with the dynamical characteristics of the flywheel. AMB's parameters are obtained by parameter identification. Influences of the magnetic force on the nutation and procession of the flywheel rotor, and of the controller to the stability of the dynamical system were analyzed.Experiment has been undertaken. The flywheel has steadily past through its flexible critical speed and reached to the rotating speed of 28500RPM. Maximum tip speed is 450m/s. Maximum electrical discharge power reaches 40W. Discharge duration is 100 minutes.

Overview of wind power generation in China: Status and development

“…The Beacon Power of America has restarted the construction of a 20 MW-project in Pennsylvania in June 2013, which will be used to store and then discharge electricity into the grid when the PJM Interconnection L. L. C. needs to balance the supply and demand of the grid as well as maintain a stable frequency [129]. In China, Tsinghua University, Southeast University and Beihang University have carried out related research works with FESS [130][131][132]. In conclusion, FESS is a new approach to utilize the wind energy economically and efficiently.…”

Modelling, simulation and performance comparison of different membership functions based fuzzy logic control for an active magnetic bearing system

“…Absence of physical contact in AMBs enables numerous advantages like, very high speed rotation, increased reliability, low power consumption [4], low frictional losses, operates in extreme temperature, lower maintenance cost and higher life time [5]. AMBs are commonly utilised in a variety of commercial and industrial applications like magnetic levitation trains [6], flywheel energy storage [7,8], magnetically suspended wheel (MSW) for satellite application [9], in several ventricular assist systems as heart pump [10,11], in turbomachinery and centrifuges, in vacuum and super clean room technique [12]. As, all types of magnetic bearings (i.e.…”

Analysis and design method of a combined radial–axial magnetic bearing based on asymmetric factor

“…It has been widely applied in many areas [1–7]. Usually, one axial bearing and two radial bearings are used to realise five degrees of freedom (DOFs) suspension [8–13]. For reducing the cost, size, and saving energy and increasing power density, combined radial–axial MB (CRAMB) becomes a good choice for a high speed motor.…”