Multi-Channel Constant Current (MC3) LED Driver for Indoor LED Luminaries

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dc.contributor.authorWu, Haoranen
dc.contributor.committeechairLee, Fred C.en
dc.contributor.committeememberMattavelli, Paoloen
dc.contributor.committeememberStilwell, Daniel J.en
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2014-03-14T20:48:01Zen
dc.date.adate2011-12-07en
dc.date.available2014-03-14T20:48:01Zen
dc.date.issued2011-11-14en
dc.date.rdate2011-12-07en
dc.date.sdate2011-11-16en
dc.description.abstractRecently, as a promising lighting source, light-emitting diodes (LEDs) have become more and more attractive and have great opportunity to replace traditional lighting sources - incandescent, fluorescent and HID because of the advantages such as high luminous efficacy, long lifetime, quick on/off time, wide color gamut, eco-friendly etc. Based on the research from U.S. Department of Energy, over 30% of total electric consumption in U.S. each year is for lighting, 75% of which are for indoor lighting (including both residential and commercial buildings). In the indoor LED lighting application, to provide multiple current source outputs for multiple LED strings, traditional solutions usually adopt a two-stage structure, which is complicated and cost-ineffective. How to design a simple, low-cost and efficient LED driver with multiple current source outputs is in great demand and really challenging. In this thesis, a single-stage multi-channel constant current (MC3) LED driver structure has been proposed. Multiple transformer structure is utilized to provide multiple current source outputs. The current control scheme is also simple - only one LED string current is sensed and controlled; other strings' currents are cross regulated. Firstly, a PWM half bridge topology is chosen to implement the proposed single-stage MC3 LED driver concept. In order to analyze the current cross regulation, a general model is derived. The circuit has been simulated under various LED load conditions to verify its good current sharing capability. In order to further improve efficiency, simplify the driver's complexity and reduce cost, a LLC resonant topology is also investigated. LLC current gain characteristic has been derived by considering LED's i-v character and a design procedure is developed. A 100 kHz, 200 W, 4-string MC3 LLC LED driver is designed and tested. The experimental results show that the driver can maintain constant current output within the whole input and output variations, achieve good efficiency and realize current sharing under both balanced and unbalanced LED conditions. The dimming function can also be realized through frequency modulation method and burst mode control method. As a conclusion, a single-stage MC3 LED driver concept is proposed and implemented with two topologies. The proposed idea provides a simple, low-cost and efficient solution for indoor LED lighting application with multiple LED string configuration. It also has good current sharing capability and robustness to LED forward voltage variations or short failures.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-11162011-101144en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11162011-101144/en
dc.identifier.urihttp://hdl.handle.net/10919/35727en
dc.publisherVirginia Techen
dc.relation.haspartWu_H_T_2011_revised.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectMulti-channel constant current (MC3) LED driveren
dc.subjectCurrent sharingen
dc.subjectLight-emitting diode (LED)en
dc.subjectDimmingen
dc.subjectLLC resonant converteren
dc.titleMulti-Channel Constant Current (MC3) LED Driver for Indoor LED Luminariesen
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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