A High efficiency high power led driver with fault tolerance and multiple led load driving using a coupled Cuk converter

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dc.contributor.advisor Gitau, Michael Njoroge
dc.contributor.postgraduate Sayyid, Ahmed Ali
dc.date.accessioned 2014-04-01T09:12:59Z
dc.date.available 2014-04-01T09:12:59Z
dc.date.created 2013-09-04
dc.date.issued 2013 en_US
dc.description Dissertation (MEng)--University of Pretoria, 2013. en_US
dc.description.abstract Lighting consumes approximately 20-25% of the energy produced worldwide. LED based lighting is rapidly becoming the preferred choice over incandescent and fluorescent based lighting. LEDs have advantages such as high efficacy, long operating lifetime and excellent lumen maintenance. Therefore, to gain benefits from LEDs for lighting purposes, they must be driven with efficient drivers which maintain high LED efficacy and long LED lifetime. A review of existing LED drivers is done, and their advantages and drawbacks are identified. Existing fault-tolerant drivers are also reviewed. Several dimming methods and their effects on the LED efficacy and lifetime are investigated. As a result, a converter with coupled inductors, suitable as an LED driver which has high efficiency and can maintain high LED efficacy, incorporated with a high efficiency dimming method, is chosen. For the proposed LED driver, a comprehensive analysis on the effects of coupling type and coupling coefficient on converter performance is done. This is carried out to establish the best coupled inductor structure and coupling coefficient, for the proposed LED driver. The coupled inductor obtained is used to achieve high LED efficacy and also used to eliminate the need for an output filtering capacitor. This results in a highly compact, high efficiency and low cost LED driver. A lossless method of LED string current sensing is proposed, so that driver efficiency is not negatively impacted. The LED driver and a digital control system are designed, with the fault-tolerant feature incorporated. The LED driver and the control system are simulated and practically implemented. The results obtained show excellent LED driver performance. The fault-tolerant feature can enable the driver to operate under fault conditions, saving repair costs and down time. Additionally, a novel digitally controlled LED driver, which can drive several independent multiple LED loads, is proposed. This novel driver is simulated and practically implemented; with the results showing excellent driver performance. The novel LED driver can simplify and reduce costs of existing LED lighting systems. en_US
dc.description.availability Unrestricted en_US
dc.description.department Electrical, Electronic and Computer Engineering en_US
dc.description.librarian gm2014 en_US
dc.identifier.citation Sayyid, AA 2013, A High efficiency high power led driver with fault tolerance and multiple led load driving using a coupled Cuk converter, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd<> en_US
dc.identifier.other E13/9/1030/gm en_US
dc.identifier.uri http://hdl.handle.net/2263/37318
dc.language.iso en en_US
dc.publisher University of Pretoria en_ZA
dc.rights © 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. en_US
dc.subject LED en_US
dc.subject Cuk en_US
dc.subject Coupled inductor en_US
dc.subject Digital control en_US
dc.subject DSP en_US
dc.subject Multiple LED load driver en_US
dc.subject Fault-tolerant LED driver en_US
dc.subject UCTD
dc.title A High efficiency high power led driver with fault tolerance and multiple led load driving using a coupled Cuk converter en_US
dc.type Dissertation en_US


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