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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Self-stabilizing magnetic bearings for flywheels

Basore, Paul Alan January 1982 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 212-215. / by Paul Alan Basore. / Ph.D.
12

Design and analysis of a composite flywheel preload loss test rig

Preuss, Jason Lee 30 September 2004 (has links)
Flywheel energy storage units have become a viable alternative to electrochemical batteries in applications such as satellites, uninterrupted power supplies, and hybrid vehicles. However, this performance is contingent upon safe operation since these flywheels can release their stored energy almost instantaneously upon failure. The research presented here investigates a health monitoring technology that may give an early indication of degraded material properties in a concentric ring composite flywheel. The existence of degraded material properties is manifested as a change in mass eccentricity due to asymmetric growth of the outermost flywheel ring. A test rig concept to investigate the technology is developed in detail using a systems engineering design process. Successful detection of the change in mass eccentricity was verified analytically through dynamic modeling of the flywheel rotor and magnetic suspension system. During steady state operation detection was determined to be feasible via measurements of the magnetic bearing currents and shaft position provided by the magnetic suspension feedback sensors. A rotordynamic analysis was also conducted and predicts successful operation to the maximum operating speed of 50,000 Rpm.
13

Design and analysis of a composite flywheel preload loss test rig

Preuss, Jason Lee 30 September 2004 (has links)
Flywheel energy storage units have become a viable alternative to electrochemical batteries in applications such as satellites, uninterrupted power supplies, and hybrid vehicles. However, this performance is contingent upon safe operation since these flywheels can release their stored energy almost instantaneously upon failure. The research presented here investigates a health monitoring technology that may give an early indication of degraded material properties in a concentric ring composite flywheel. The existence of degraded material properties is manifested as a change in mass eccentricity due to asymmetric growth of the outermost flywheel ring. A test rig concept to investigate the technology is developed in detail using a systems engineering design process. Successful detection of the change in mass eccentricity was verified analytically through dynamic modeling of the flywheel rotor and magnetic suspension system. During steady state operation detection was determined to be feasible via measurements of the magnetic bearing currents and shaft position provided by the magnetic suspension feedback sensors. A rotordynamic analysis was also conducted and predicts successful operation to the maximum operating speed of 50,000 Rpm.
14

Design and optimization of a material property distribution in a laminated composite flywheel /

Thielman, Scott C. January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [116]-117).
15

Passive stabilization of flywheel magnetic bearings

Basore, Paul Alan January 1980 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 218-223. / by Paul Alan Basore. / M.S.
16

Control designs for low-loss active magnetic bearing theory and implementation /

Wilson, Brian Christopher David. January 2004 (has links) (PDF)
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004. / Habetler, Thomas, Committee Member ; Sadegh Nader, Committee Member ; Taylor David, Committee Member ; Tsiotras Panagiotis, Committee Co-Chair ; Heck-Ferri Bonnie, Committee Co-Chair. Vita. Includes bibliographical references (leaves 319-326).
17

Characterization and dynamic analysis of damping effects in composite materials for high-speed flywheel applications

Moreira, Alfonso, January 2007 (has links) (PDF)
Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 92-97)
18

Energy storage in composite flywheel rotors

Janse van Rensburg, Petrus J. 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: As the push continues for increased use of renewables on the electricity grid, the problem of energy storage is becoming more urgent than ever. Flywheels with wound, composite rotors represent an efficient and environmentally friendly option for energy storage. They have already been applied successfully for voltage control on electrical rail networks and for bridging power in backup UPS systems, but lately they have also proven useful for grid-scale frequency regulation. For flywheels to be deployed on a wider scale, the high cost associated with the technology will have to be addressed. An important driver of cost is the density at which energy can be stored. Currently, flywheel designs do not consistently achieve high energy density, and this study investigates the reasons for this. A critical analysis is made of the design methodologies that have been proposed in the available literature, and some improvements are suggested. Most notably it is shown that significant improvements in energy density may be possible if the design optimization problem is formulated carefully. In addition, the problem of material selection is discussed, because material properties have a significant influence on energy density. Some guidance is given for flywheel designers on how to choose an optimal set of materials without invoking undue computational effort. It is hoped that these suggestions may be carried forward as a topic of further research. / AFRIKAANSE OPSOMMING: Namate die aanvraag vir hernubare energie op die elektrisiteit netwerk vergroot, word die probleem van energie berging van kardinale belang. Vliegwiele met silindriese rotors van samegestelde materiale bied ’n effektiewe en omgewingsvriendelike opsie vir energieberging. Hierdie tipe vliegwiele is reeds suksesvol aangewend vir spanningsbeheer op elektriese spoornetwerke en om oorbruggingskrag te voorsien aan rugsteun sisteme. Meer onlangs is hulle ook nuttig bewys vir die regulasie van frekwensie op die elektrisiteit netwerk. Grootskaalse aanwending van vliegwiele kan egter slegs oorweeg word indien die hoë koste van die tegnologie aangespreek word. Een van die onderliggende redes vir die hoë koste van vliegwiele is die relatiewe lae digtheid waarby energie geberg kan word, en hierdie studie ondersoek die redes hiervoor. Die ontwerpmetodiek wat in die beskikbare literatuur voorgestel is, word krities geanaliseer en ’n paar verbeteringe word aanbeveel. Mees noemenswaardig is die opmerklike verbeteringe in energie-digtheid wat soms moontlik is indien die optimerings-probleem deurdag geformuleer word. Omdat materiaaleienskappe ’n bepalende invloed op energie digtheid uitoefen word die probleem van materiaalseleksie ook verder bespreek. ’n Paar riglyne vir die seleksie van ’n optimale stel materiale sonder om oordrewe berekenings-inspanning te veroorsaak, word aan vliegwielontwerpers gegee. Hierdie voorstelle kan hopelik in die toekoms verder deurgetrap word as onderwerp vir verdere studies.
19

A field-modulated, variable-speed to constant-frequency power converter

Bliamptis, Tim Emmanuel January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 109-110. / by Tim Emmanuel Bliamptis. / M.S.
20

Design and construction of a bidirectional DCDC converter for an EV application

Hedlund, Magnus January 2010 (has links)
<p>A Sliding Mode Control System for a Bidirectional DCDC Converter was designed and a low voltage prototype was constructed. The control system based its decisions solely on the latest available measurements, which improves performance when changing operative quadrant, since no memory needs reinitializing (such as for PI and state prediction methods). A boost control philosophy was presented, based on a current source approximation. The control was found to be stable without steady-state errors when the variance of the input/output dynamics was high.</p><p>The target application for the DCDC Converter is an EV (Electric Vehicle) with a flywheel driveline, which puts additional requirements of the converter. Among these are current and voltage control, bidirectionality, and a broad input voltage range.</p><p>Simulations were performed in Simulink prior to physical implementation, proving functionality of the proposed control system. The physical implementation of the control was done on a digital signal processor with code compiled from C. A median filter was designed to increase measurement efficiency for the current sensors which had shot-like noise distortions.</p>

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