04-12-2012, 05:04 PM
A Flywheel Energy Storage System with Active Magnetic
Bearings
A Flywheel Energy Storage System.pdf (Size: 306.37 KB / Downloads: 68)
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.
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer]
Keywords: Energy storage system, Flywheel, Active magnetic bearing
1. Introduction
Flywheel has a long application history in mechanical industry.[1] In recent years, it attracts more and
more researchers as an energy storage method. The advantages for a flywheel energy storage system
(FEES) include high density of power output, long life-span, and environmentally friendly.
The FEES can be used in the cases where large power is needed in short time, for examples , city bus,
frequent light train, braking power regenerating, shipyard cranes, as well as for wind power and smart
grid energy storage.
Charge and discharge experiment
Much has been spent on the controlling process[3] including the system parameter identify, rotor
vibration data obtaining, transfer function analyzing, etc. including the gyroscopic effect control in
previous work[4]. Owing to the limit space, details of this part of work has not been given here.
The final test to evaluate the system is the charge and discharge experiment. The results are plotted in
Fig.4 and Fig.5.