高功因PWM調光之LED驅動器

A PWM Dimmed LED Driver Featuring High Power Factor

林睦耀(Mu-Yao Lin)

指導教授 ： 鄭宏良

義守大學/電機資訊學院/電機工程學系/碩士(2017年)

摘要

本文提出結合降升壓型轉換器與降壓型轉換器之交流-直流高功因可調光之發光二極體(LED)驅動器。電路使用一個功率電晶體作為主動開關，而主動開關之閘極電壓為一低頻封包內含有高頻脈波之驅動訊號。降升壓型轉換器作為功因修正電路，並設計電感電流工作於不連續電流模式(DCM)，以達到高功率因數之目的；降壓型轉換器作為直流-直流轉換器，並設計電感電流工作於連續電流模式(CCM)，以降低輸出電流漣波。而調整主動開關之低頻訊號導通率即可改變LED之平均電流，進而達到LED調光之目的。

本文針對電路之工作模式詳作分析，並設計製作60W LED驅動器之雛形電路，經由理論推導與實驗結果顯示所提電路之可行性。由實驗結果顯示，於額定功率下之整體電路轉換效率為87.68%；功率因數高達0.997；電流總諧波失真率為1.852%。

關鍵字

降升壓型轉換器 ； 降壓型轉換器 ； 調光 ； 發光二極體 ； 功率因數修正 ； 脈波寬度調變 ； 電流總諧波失真

並列摘要

This thesis proposes a high power factor dimmable LED driver that consists of a buck-boost converter and a buck converter. The circuit adopts a power MOSFET as the active switch. The gate voltage of the MOSFET is a signal that consists of high-frequency pulses within a low-frequency pulse. The buck-boost converter serves as a power-factor corrector (PFC) where the inductor is operated at discontinuous conduction mode (DCM) to achieve an unity power factor. The buck converter serves as a DC-DC converter where the current of inductor is operated in continuous conduction mode (CCM) to reduce the ripple of the output current. The duty ratio of the low- frequency pulse is adjusted to control the LED average current for dimming operation.

The detail circuit operation and analysis are provided. A prototype circuit of a 60-W LED driver was built and tested. The feasibility of the proposed circuit is demonstrated by theoretical derivation and experimental results. The measured circuit efficiency, the power factor, and the total current harmonic distortion at the rated power operation are 87.68%, 0.997 and 1.852%, respectively.

並列關鍵字

Buck-Boost Converter ； Buck Converter ； Dimming ； Light-Emitting Diode ； Power-Factor Correction ； Pulse-Width-Modulation ； Total Current Harmonic Distortion

參考文獻

[7]Sang Cheol Moon, Gwan-Bon Koo, and Gun-Woo Moon, “Dimming-Feedback Control Method for TRIAC Dimmable LED Drivers,” IEEE Transactions on Industrial Electronics, Vol. 62, No. 2, pp. 960-965, Feb. 2015.

[9]Weiyi Feng, Fred C. Lee, and Paolo Mattavelli, “Optimal Trajectory Control of LLC Resonant Converters for LED PWM Dimming,” IEEE Transactions on Power Electronics, Vol. 29, No. 2, pp. 979-987, 2014.

[10]Chin-Sien Moo, Yu-Jen Chen, and Wen-Ching Yang, “An Efficient Driver for Dimmable LED Lighting,” IEEE Transactions on Power Electronics, Vol. 27, No. 11, pp. 4613-4618, 2012.

[15]Praveen Kumar Singh, Bhim Singh, and Vashist Bist, “PFC Converter Based Power Quality Improvement and Ripple Current Minimization in BLDC Motor Drive,” IEEE International Conference on Power Systems (ICPS), pp. 1-6, 2016.

[16]Manuel Arias, Diego G. Lamar, Francisco F. Linera, Didier Balocco, Almadidi Aguissa Diallo, and Javier Sebastián, “Design of a Soft-Switching Asymmetrical Half-Bridge Converter as Second Stage of an LED Driver for Street Lighting Application,” IEEE Transactions on Power Electronics, Vol. 27, No. 3, pp. 1608-1621, 2012.