由於LED具有高發光效率、堅固耐用、使用壽命長以及體積小等優點，於許多場合上LED逐漸取代螢光燈泡或傳統白熾燈泡，成為照明裝置之主要發展趨勢，因此本論文之主要目標為研製一兼具低成本及高效率之LED驅動器。

本論文之主要貢獻可摘要如下:第一點貢獻為提出一新型具低電壓切換之可調光式LED驅動器，其元件數量相對於基本型降壓轉換器僅需額外增加一共振電感，因此其具備成本低與可靠度高之優點，且其主動開關作低電壓切換，二極體作零電流切換，可降低切換損失以提高效率，且當其應用於主動式負載如LED等時，其具有高責任週期利用率，可達到高調光解析度之效果；第二點貢獻為分析本驅動器之工作原理與穩態特性並提出設計方法，接著分別採用降階平均模型與全階平均模型建模方法推導此驅動器之直流與小訊號模型，並求出其轉移函數以作為閉迴路控制器之設計依據。雖然降階平均模型法可推得較簡化之模型，然而全階平均模型法能提供較高之精確度；第三貢獻點為本論文所研製驅動器之控制器除了責任週期回授控制外，並同時加入變頻控制，可以大幅增加驅動器之暫態響應速度。第四貢獻點為實體製作一額定功率50W之雛型可調光驅動器，經由模擬與實測結果之比對，以驗證本論文所提驅動器之可行性。經由實驗可知，該驅動器最高效率可達96.06%且具備較高的調光解析度，非常適合LED調光之應用。

關鍵字：LED驅動器、低電壓切換、零電流切換、降階平均模型、全階平
均模型、變頻控制

Due to the advantages of high luminous efficacy, ruggedness, long life hours and compact size of LED, it has now become a main trend to replace the traditional lamps in many applications. Therefore, the main objective of this thesis is focused on developing a LED driver with low cost and high efficiency.

The major contributions of this thesis may be summarized as follows. First, a novel dimmable LED driver topology with low voltage switching (LVS) is proposed. Compared with the conventional buck converter, only one additional resonant inductor is needed which results in low cost and high reliability. Both the low voltage switching of the active switch and the zero current switching (ZCS) of the diode can reduce switching losses and raise the efficiency rather significantly. Also, the wide duty ratio operating range of the proposed driver renders much higher dimming resolution for active load cases such as LED dimming application. Secondly, theoretical analysis of the proposed LED driver is made and some design guidelines are given. The mathematical models of the proposed LED driver are derived based on reduced-order average modeling technique and full-order average modeling technique for the design of the closed-loop control. Although the former can result in a more simplified model, however, the latter can provide better accuracy. Thirdly, in addition to the duty ratio feedback control, the switching-frequency control can also be coordinated in the closed-loop controller simultaneously to improve greatly the transient response of the driver. Finally, a 50W prototype is constructed for verifying the effectiveness of the proposed LED driver. Experimental results show that the maximum efficiency is up to 96.06% and high dimming resolution is available which makes the proposed LED driver suitable for LED dimming application.

Keywords: LED Driver, LVS, ZCS, Reduced-Order Average Modeling,
Full-Order Average Modeling, Switching-Frequency Control.

摘 要 I
英文摘要 II
誌 謝 IV
目 錄 V
圖 目 錄 VII
表 目 錄 XI
第一章 緒 論 1
1.1 研究動機 1
1.2 文獻回顧 2
1.3 本論文之貢獻 3
1.4 論文內容概述 3
第二章 LED特性簡介與傳統直流降壓型轉換器簡介 5
2.1 前言 5
2.2 LED特性簡介 5
2.3 基本型降壓轉換器簡介 6
2.4 新型具零電壓切換降壓轉換器簡介 10
2.5 耦合電感型具零電壓切換降壓轉換器簡介 19
第三章 新型具零電壓切換LED驅動器特性分析 27
3.1 前言 27
3.2 新型驅動器架構與工作原理 28
3.3 新型驅動器穩態特性分析 33
3.4 新型驅動器數學模型推導 48
第四章 實體電路製作與量測結果 64
4.1 前言 64
4.2 功率級電路製作 65
4.3 控制級電路實現 72
4.4 模擬與實測結果 78
第五章 結 論 93
5.1 論文內容總結 93
5.2 未來工作 94
參考文獻 96

[1] 「2012年能源產業技術白皮書」，經濟部能源局，2012年5月。
[2] 「科學發展月刊第483期」，行政院國家科學委員會，2013年3月。
[3] H. L. Do, “Zero-voltage-switching synchronous buck converter with a coupled inductor,” IEEE Transactions on Industrial Electronics, Vol. 58, No. 8, pp. 3440-3447, August 2011.
[4] Y. C. Chuang and Y. L. Ke, “A novel high-efficiency battery charger with a buck zero-voltage-switching resonant converter,” IEEE Transactions on Energy Conversion, Vol. 22, No. 4, pp. 848-854, Decemver 2007.
[5] P. Das, B. Laan, S. A. Mousavi, and G. Moschopoulos, “A nonisolated bidirectional ZVS-PWM active clamped DC–DC Converter,” IEEE Transactions on Power Electronics, pp. 1345-1351, February 2009.
[6] K. Rahimi, A. N. Motlagh, and M. Pakdel, “A novel soft-switched synchronous buck converter,” Proceedings of the 2009 IEEE Vehicle Power and Propulsion Conference (VPPC), pp. 1345-1351, September 2009.
[7] B. ChittiBabu, S. R. Samantaray, N. Saraogi, M. V. A. Kumar, R. Sriharsha, and S. Karmaker, “Synchronous buck converter based PV energy system for portable applications,” Proceedings of the 2011 IEEE Students’ Technology Symposium (TechSym), pp. 335-340, January 2011.
[8] J. Zhao, “Non-isolation soft-switching buck converter for high-step-down conversion,” Proceedings of the 2009 31st International Telecommunications Energy Conference (INTELEC), pp. 1-6, October 2009.
[9] Y. C. Chuang, “High-efficiency ZCS buck converter for rechargeable batteries,” IEEE Transactions on Industrial Electronics, Vol. 57, No. 7, pp. 2463-2472, July 2010.
[10] J. Zhao, “A novel ZVS buck converter topology for VRM applications,” Proceedings of the 2011 6st IEEE Conference on Industrial Electronics and Applications (ICIEA), pp. 2374-2379, June 2011.
[11] L.Jiang, C. C. Mi, C. Yin, and J. Li, “An improved soft-switching buck converter with coupled inductor,” IEEE Transactions on Power Electronics, Vol. 28, No. 11, pp. 4885-4891, November 2013.
[12] F. Zhang, F. Z. Peng, and Z. Qian, “Study of the multilevel converters in DC-DC applications,” Proceedings of the 2004 35th Annual Power Electronics Specialists Conference (PESC), Vol. 24, pp. 2249-2258, October 2009.
[13] J. P. Rodrigues, S. A. Mussa, M. L. Heldwein, and A. J. Perin, “Three-level ZVS active clamping PWM for the DC–DC buck converter,” IEEE Transactions on Power Electronics, Vol. 28, No. 11, pp. 4885-4891, Nonember 2013.
[14] W. Yu and H. Ma, “Single-switch three-level DC-DC converters for dimmable LED lighting,” Proceedings of the 2008 IEEE Applied Power Electronics Conference and Exposition (APEC), pp. 735-740, March 2011.
[15] J. P. Rodrigues, I. Barbi, and A. J. Perin, “Buck converter with ZVS three level buck clamping,” Proceedings of the 2008 IEEE Power Electronics Specialists Conference (PESC), pp. 2184-2190, June 2008.
[16] A. E. Demian, C. H. G. Treviso, C. A. Gallo, and F. L. Tofoli, “Non-isolated DC-DC converters with wide conversion range used to drive high-brightness LEDs,” Proceedings of the 2009 Brazilian Power Electronics Conference (COBEP), pp. 598-605, September 2009.
[17] 中國LED網，「LED燈發光原理、結構、產品分類匯總」，網址: http://www.cnledw.com/tech.detail-22499.htm，2011年5月4日。
[18] W. Eberle, Z. Zhang, Y. F. Liu, and P. C. Sen, “A practical switching loss model for buck voltage regulators,” IEEE Transactions on Power Electronics, Vol. 24, No. 3, pp. 700-713, November 2013.
[19] M. Chen and J. Sun, “Reduced-order averaged modeling of active-clamp converters,” IEEE Transactions on Power Electronics, Vol. 21, No. 2, pp. 487-494, March 2006.
[20] F. H. Dupont, C. Rech, R. Gules, and J. R. Pinheiro, “Reduced-order model and control approach for the boost converter with a voltage multiplier cell,” IEEE Transactions on Power Electronics, Vol. 28, No. 7, pp. 3395-3404, July 2013.
[21] J. Sun and H. Grotstollen, “Averaged modeling of switching power converters: reformulation and theoretical basis,” Proceedings of the 1992 23rd Annual IEEE Power Electronics Specialists Conference (PESC), Vol. 2, pp. 1165-1172, June 1992.
[22] J. Sun, D. M. Mitchell, M. F. Greuel, P. T. Krein, and R. M. Bass, “Averaged modeling of PWM converters operating in discontinuous conduction mode,” IEEE Transactions on Power Electronics, Vol. 16, No. 4, pp. 482-492, July 2001.
[23] J. Sun and H. Grotstollen, “Averaged modeling and analysis of resonant converters,” Proceedings of the 1993 24th Annual IEEE Power Electronics Specialists Conference (PESC), pp. 707-713, June 1993.
[24] Mohan, Undeland, and Robbins, “Power Electronics,” John Wiley & Sons, INC. 2003.
[25] EPARC，電力電子學綜論，全華圖書股份有限公司，2007年2月。