A Study on Driving Technology of Semiconductor Lighting

• Main Authors: Po-Chien Hsu, 許伯堅
• Other Authors: 黃秉鈞
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/98942457839868536544

碩士 === 國立臺灣大學 === 機械工程學研究所 === 93 === The main purpose of this research is to investigate the driving control technology of high power LED in order to improve the reliability under various operating and environmental conditions. Different driver designs are also studied in order to increase LED energy efficiency. System dynamics model for a LED luminare is first identified experimentally. A feedback control system for constant-current driving using PI controller was designed and analyzed. An optimal controller was determined using the closed-loop sensitivity function. For verification purpose, a 96W LED luminare was designed and built. The control system was implemented on a PIC microprocessor. Experimental results show that the control system can stably and accurately control the current at a constant value at the variation of ambient temperature up to 35oC and the chip junction can be maintained at a temperature lower than 105oC. It is also shown that the design of luminare will not affect the control system performance. Another driver using constant-voltage and PWM technique was also studied to improve the lighting efficiency. Test results for the luminance measurement show that PWM driver could not improve the power consumption even for PWM frequency up to 20 kHz.