scholarly journals A Flywheel Energy Storage and Conversion System for Solar Photovoltaic Applications

Author(s):  
A. R. Millner

A low-drag, low-power magnetic bearing and a permanent magnet brushless d-c motor-generator have been developed for a satellite flywheel. These will be combined with a terrestrial flywheel and control electronics to make up a flywheel energy storage and conversion system for use in a stand-alone solar photovoltaic residence. Technical and economic performance analyses indicate that, contrary to general thought, a flywheel system will be competitive if not superior to more conventional systems utilizing either present-day or advanced batteries. This derives from the ability of the flywheel to perform the functions of d-c to a-c inversion and optimal impedance matching between the PV arrays and the load in addition to providing energy storage. The motor-generator design will also be discussed. This paper describes the structural topology, performance data, design parameters, and test measurements of the magnetic bearing and motor-generator as well as a description of the flywheel and control electronics to be used. A preliminary discussion of the economic aspects is also included.

1997 ◽  
Vol 119 (4) ◽  
pp. 650-656 ◽  
Author(s):  
J. D. Stienmier ◽  
S. C. Thielman ◽  
B. C. Fabien

This article presents the design, dynamic analysis, and control of a flywheel energy storage system. At the heart of the system is a hybrid magnetic bearing. The bearing consists of ring and disk shaped permanent magnets, and a synthetic ruby sphere on a sapphire plate. The bearing is shown to be stable without active control. Equations of motion for the flywheel are derived in a sensor based coordinate system. The resulting equations are non-singular around the nominal operating condition and are feedback linearizable without the need for a coordinate transformation. A method of modeling rotor imbalance as a set of sinusoidal disturbances of magnitudes that do not depend on rotational speed is also presented. To reject large external disturbances active control is applied to the flywheel. Two nonlinear control laws are applied and are shown to improve the initial condition response of the inherently stable system.


Author(s):  
Shuyun Jiang ◽  
Yujiang Qiu

This technical note aims to reduce friction power loss of flywheel energy storage system (FESS) supported by hydrodynamic spiral groove bearing and permanent magnetic bearing (PMB). An approach is proposed to fabricate the spiral groove bearing using polytetrafluoroethylene (PTFE) composite. A test rig is developed to test tribological properties of the spiral groove PTFE bearings. Also, two PTFE composites (C-PTFE: 80 vol.% PTFE filled with 20 vol.% graphite; C-Cu-PTFE 50 vol.% PTFE filled with 20 vol.% graphite and 30 vol.% copper powder) are tested. Results show that the friction power losses of the C-PTFE and C-Cu-PTFE bearings are lower than that of the traditional albronze (CuAl) bearing in the whole speed range. In addition, the spiral groove PTFE bearings show an excellent friction-reducing property under boundary or mixed lubrication condition. Finally, a case study is given to show the spiral groove PTFE bearing is capable of reducing the friction power loss of the FESS.


Cryogenics ◽  
2016 ◽  
Vol 80 ◽  
pp. 234-237 ◽  
Author(s):  
Yoshiki Miyazaki ◽  
Katsutoshi Mizuno ◽  
Tomohisa Yamashita ◽  
Masafumi Ogata ◽  
Hitoshi Hasegawa ◽  
...  

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