A PWM Constant Average Current Driving Technique for Solar LED Lighting Systems

獨立型太陽能LED照明系統之定電流PWM驅動控制器

黃秉鈞(Bin-Juine Huang) ； 吳民聖(Min-Sheng Wu) ； 許伯堅(Po-Chien Hsu) ； 陳俊瑋(Chun-Wei Chen) ； 陳國揚(Kuo-Yang Chen)

《中國機械工程學刊》 30卷6期 (2009/12) Pp. 455-465

https://doi.org/10.29979/JCSME.200912.0002

摘要

獨立型太陽能LED照明系統，於白天時利用鉛蓄電池，蓄存太陽電池陣列所產生之電力，並於夜晚點亮LED燈具。鉛蓄電池放電時，其輸出端電壓會隨蓄電量改變，容易造成LED燈具於驅動時之損壞，故一般利用直流變壓器，將蓄電池變動之電壓，轉換為LED之驅動電流（或電壓），此直流變壓器即會增加系統成本、降低系統可靠度，並具有約15%之能量損失。本文旨在發展定電流PWM驅動控制器，可利用電池輸出電壓直接驅動LED燈具，並探討此驅動方式對LED之壽命、照度之影響。由結果可知，在3倍瞬間大電流驅動下，PWM驅動方式對LED壽命不會造成影響；利用24V系統之整體照度損失約為10.7%至13.1%。由結果顯示，定電流PWM驅動控制器能取代傳統太陽能系統之直流變壓器，增加獨立型太陽能LED照明系統之可靠度。

並列摘要

A stand-alone solar LED lighting system usually consists of a DC/DC converter to convert the floating battery voltage into a constant current to drive the LED. A 15% energy loss of the DC/DC converter will be introduced. The DC/DC converter may also increase system costs and reduce system reliability due to its additional components. The present study develops a PWM technique to drive the LED luminaire directly from the battery output using the PWM's constant average current. However, the instantaneous current stress may decrease the overall light efficiency of an LED luminaire when it is driven by a PWM current. The result shows that the overall lighting efficiency loss is between 10.7% to 13.1% for a junction temperature at 70℃ when using a 24V battery system. This study shows that the direct PWM driving technique is feasible and able to drive an LED directly from battery output in a stand-alone solar system. Removing the traditional DC/DC converter increases system reliability and reduces system costs.

並列關鍵字

constant average driving technique ； stand-alone solar LED lighting system ； LED direct PWM driving technique ； pulse-driven LED