https://scholars.lib.ntu.edu.tw/handle/123456789/411421
標題: | Reliability test of LED driven by PWM technique | 作者: | Huang B.J. Wu M.S. Tang C.W. Hsu P.C. Chen J.W. Chen K.Y. |
關鍵字: | DC current stress; LED driving technique; LED reliability test; Pulse current stress; Solar-powered LED lighting system | 公開日期: | 2008 | 卷: | 7048 | 來源出版物: | Proceedings of SPIE - The International Society for Optical Engineering | 摘要: | The solar-powered LED lighting system has been commercialized for a long time. The system usually consists of a DC to DC converter in order to convert the battery voltage into a fixed voltage or current for the LED lighting luminaire. This will cause energy loss and system reliability due to the failure of DC/DC converter. In the present study, we develop a special technique to drive the LED luminaire directly from battery utilizing PWM technique in order to remove the DC/DC converter. However, instantaneous current overdriven can occur easily due to the variation of battery voltage with the state-of-charge of battery. In the present study, we setup a thermal chamber with temperature variation to within 40±3°C. A LED luminaire was specially designed for the LED reliability test with four different circuits with each circuit connecting three LED lamps serially. A driver is designed to provide 4 kinds of power inputs to LED: (a) 350mA constant current, (b) 700mA,100Hz, duty cycle=50%, (c)700mA, 10K Hz duty cycle=50% and (d) 1050mA, 100Hz, duty cycle=33%. The tests were performed simultaneously to compare light decay between normal drive condition (a) and other PWM driving conditions (b, c, d). The accumulated total test time so far is more then 7,032 hours and has shown no significant light decay in 4 different loops. This reveals that the PWM technique directly driven by battery is feasible and is able to reduce energy loss of DC to DC converter in the solar lighting system. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-56249114482&doi=10.1117%2f12.797396&partnerID=40&md5=e1fc8d10cb0341477bc08adfe582dbcb https://scholars.lib.ntu.edu.tw/handle/123456789/411421 |
ISBN: | 9.78082E+12 | ISSN: | 0277786X | DOI: | 10.1117/12.797396 | SDG/關鍵字: | Counting circuits; Electron energy loss spectroscopy; Energy dissipation; HVDC power transmission; Lighting; Lighting fixtures; Networks (circuits); Photoelectric cells; Photoelectrochemical cells; Photovoltaic cells; Primary batteries; Pulse modulation; Pulse width modulation; Reliability; Solar system; Testing; Theorem proving; Battery voltages; Constant currents; Dc converters; DC current stress; Dc/dc converters; Drive conditions; Duty cycles; Energy losses; Fixed voltages; Instantaneous currents; LED lamps; LED lightings; Lighting systems; Long times; Power inputs; Pulse current stress; PWM drivings; PWM techniques; Reliability tests; Set-ups; Solar-powered LED lighting system; System reliabilities; Temperature variations; Total test times; Solar energy |
顯示於: | 機械工程學系 |
在 IR 系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。