High Efficiency SEPIC Converter For High Brightness Light Emitting Diodes (LEDs) System

dc.contributor.authorQin, Yaxiaoen
dc.contributor.committeechairLai, Jih-Shengen
dc.contributor.committeememberMeehan, Kathleenen
dc.contributor.committeememberYu, Wensongen
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2014-03-14T21:43:37Zen
dc.date.adate2012-09-14en
dc.date.available2014-03-14T21:43:37Zen
dc.date.issued2012-07-02en
dc.date.rdate2012-09-14en
dc.date.sdate2012-08-23en
dc.description.abstractThis thesis presents an investigation into the characteristics of and driving methods for light emitting diode (LED) lamp system. A comprehensive overview on the lighting development is proposed. The characteristic of the light emitting diode (LED) lamp is described and the requirements of the ballast for the light emitting diode (LED) lamp are presented. Although LED lamps have longer lifetime than fluorescent lamps, the short lifetime limitation of LED driver imposed by electrolytic capacitor has to be resolved. Therefore, an LED driver without electrolytic capacitor in the whole power conversion process is preferred. In this thesis, a single phase, power factor correction converter without electrolytic capacitors for LED lighting applications is proposed, which is a modified SEPIC converter working in discontinuous conduction mode (DCM). Different with a conventional SEPIC converter, the middle capacitor is replaced with a valley-fill circuit. The valley-fill circuit could reduce the voltage stress of output diode and middle capacitor under the same power factor condition, thus achieving higher efficiency. Instead of using an electrolytic capacitor for the filter, a polyester capacitor of better lifetime expectancy is used. An interleaved power factor correction SEPIC with valley fill circuit is proposed to further increase the efficiency and to reduce the input and output filter size and cost. The interleaved converter shows the features such as ripple cancellation, good thermal distribution and scalability.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-08232012-143512en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08232012-143512/en
dc.identifier.urihttp://hdl.handle.net/10919/44422en
dc.publisherVirginia Techen
dc.relation.haspartQin_Y_T_2012.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSEPICen
dc.subjectInterleaved converteren
dc.subjectElectrolytic capacitoren
dc.subjectLight emitting diodeen
dc.subjectPower Factor Correctionen
dc.subjectLong lifetime LED driveren
dc.titleHigh Efficiency SEPIC Converter For High Brightness Light Emitting Diodes (LEDs) Systemen
dc.typeThesisen
thesis.degree.disciplineElectrical and Computer Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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