Analysis and feedback control of magnetic bearings with reference to flywheel energy storage.

 

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dc.contributor.advisor Enslin, NC de V en_ZA
dc.contributor.author Bredenkamp, Gordon Leslie en_ZA
dc.date.accessioned 2014-09-22T07:51:09Z
dc.date.available 2014-09-22T07:51:09Z
dc.date.issued 1984 en_ZA
dc.identifier.citation Bredenkamp, G. 1984. Analysis and feedback control of magnetic bearings with reference to flywheel energy storage. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/7585
dc.description Bibliography: leaves 132-136. en_ZA
dc.description.abstract In high speed applications magnetic bearings offer many potential advantages over mechanical bearings. The type of magnetic bearing most suitable for energy storage flywheels is selected and analysed for the purpose of designing feedback control loops. A nonlinear as well as a small signal linear model of the "current driven" magnetic bearing with unlaminated magnetic components is derived. Subsequently describing functions characterising the small- as well as large signal behaviour of the same bearing in the "voltage driven" mode, are obtained. It is shown that workable results are obtained for most practical situations by using linear systems theory, although the magnetic bearing is a nonlinear device. The describing function model enables the designer to identify the mechanisms leading to limit cycles under adverse operating conditions. Feedback control loops designed around the small signal characteristics produce practical results in the case of the "voltage driven" mode which are superior to that of the "current driven" case. An essential refinement, where energy losses and vibrations arising from rotor imbalance are eliminated, is described. A discrete time filtering technique is used. Two experimental models were built and fully tested in order to verify the above theoretical approaches. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Electrical engineering en_ZA
dc.title Analysis and feedback control of magnetic bearings with reference to flywheel energy storage. en_ZA
dc.type Doctoral Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Department of Electrical Engineering en_ZA
dc.type.qualificationlevel Doctoral
dc.type.qualificationname PhD en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Bredenkamp, G. L. (1984). <i>Analysis and feedback control of magnetic bearings with reference to flywheel energy storage</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/7585 en_ZA
dc.identifier.chicagocitation Bredenkamp, Gordon Leslie. <i>"Analysis and feedback control of magnetic bearings with reference to flywheel energy storage."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 1984. http://hdl.handle.net/11427/7585 en_ZA
dc.identifier.vancouvercitation Bredenkamp GL. Analysis and feedback control of magnetic bearings with reference to flywheel energy storage. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 1984 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/7585 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Bredenkamp, Gordon Leslie AB - In high speed applications magnetic bearings offer many potential advantages over mechanical bearings. The type of magnetic bearing most suitable for energy storage flywheels is selected and analysed for the purpose of designing feedback control loops. A nonlinear as well as a small signal linear model of the "current driven" magnetic bearing with unlaminated magnetic components is derived. Subsequently describing functions characterising the small- as well as large signal behaviour of the same bearing in the "voltage driven" mode, are obtained. It is shown that workable results are obtained for most practical situations by using linear systems theory, although the magnetic bearing is a nonlinear device. The describing function model enables the designer to identify the mechanisms leading to limit cycles under adverse operating conditions. Feedback control loops designed around the small signal characteristics produce practical results in the case of the "voltage driven" mode which are superior to that of the "current driven" case. An essential refinement, where energy losses and vibrations arising from rotor imbalance are eliminated, is described. A discrete time filtering technique is used. Two experimental models were built and fully tested in order to verify the above theoretical approaches. DA - 1984 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1984 T1 - Analysis and feedback control of magnetic bearings with reference to flywheel energy storage TI - Analysis and feedback control of magnetic bearings with reference to flywheel energy storage UR - http://hdl.handle.net/11427/7585 ER - en_ZA


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