Core loss characterization and design optimization of high-frequency power ferrite devices in power electronics applications

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dc.contributor.authorGradzki, Pawel Miroslawen
dc.contributor.committeechairLee, Fred C.en
dc.contributor.committeememberStephenson, F. Williamen
dc.contributor.committeememberChen, Dan Y.en
dc.contributor.committeememberCho, Bo H.en
dc.contributor.committeememberHendricks, Robert W.en
dc.contributor.departmentElectrical Engineeringen
dc.date.accessioned2014-03-14T21:14:03Zen
dc.date.adate2008-06-06en
dc.date.available2014-03-14T21:14:03Zen
dc.date.issued1992-03-30en
dc.date.rdate2008-06-06en
dc.date.sdate2008-06-06en
dc.description.abstractAn impedance-based core loss measurement technique for power ferrites, the modeling and analysis of mechanisms of high-frequency losses, and design methodology for optimization for high-frequency magnetics are presented. The high-frequency losses of ferrite materials are characterized employing a large-signal impedance measurement technique. The impedance analyzer controlled through an IEEE-488 interface, measures the impedance of the inductor under test under large signal excitation via a power amplifier. The core loss is a form of a parallel resistance is derived from measured impedance characteristics. A wideband impedance probe, enables core loss characterization up to 100 MHz. A comprehensive analysis of all major loss mechanisms in ferrites is presented. A new form of residual losses due to a magnetoelectric effect is postulated to account for losses at high frequencies. Two models of losses in ferrites are proposed, one with emphasis on analysis of loss mechanisms, and the other with an emphasis on the design of high-frequency magnetic components. Both models include the important effect of static bias field, which is the case in many power electronics applications. Magnetic losses due to magnetostriction are measured. Dependence of magnetoelastic resonances on the magnetic bias. core material, core shape and size is studied. The influence of diffusion after-effect on core loss under time-varying bias field is investigated. Thermal stability of high-frequency magnetics is studied. A verification of one- and two- dimensional models of winding losses for solid and litz wire is performed. The optimum design method for high-frequency power transformers and inductors is proposed.en
dc.description.degreePhDen
dc.format.extentxii, 251 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-06062008-165934en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06062008-165934/en
dc.identifier.urihttp://hdl.handle.net/10919/38366en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1992.G722.pdfen
dc.relation.isformatofOCLC# 26145465en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1992.G722en
dc.subject.lcshElectric inductors -- Designen
dc.subject.lcshElectric transformers -- Designen
dc.subject.lcshFerrite devices -- Designen
dc.subject.lcshFerrites (Magnetic materials)en
dc.subject.lcshPower electronics -- Materialsen
dc.titleCore loss characterization and design optimization of high-frequency power ferrite devices in power electronics applicationsen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePhDen

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