原油價格不斷高漲(目前已來到70美元/桶)、各種代替能源的開發，即使太陽能盛行於當今潮流，也比不上能源之有效運用；提升用電效率似乎是唯一途徑，在電源輸入端加裝功率因數修正器（Power factor corrector）提升電氣產品的功率因數是絕對必要的。
本論文採主動式功因修正器(PFC)應用於昇、降壓型返馳式轉換器，控制方法採固定MOSFET導通時間、變動切換頻率方式，以提升有效功率之應用、降低諧波產生、使得輸入電源電流與電壓產生零相位差。研究重點在於設計一個輸出功率為100W、輸出電壓為24v之切換式電源供給器，具功率因數修正之DCM/CCM Transition Mode 返馳式轉換器，實作以L6561作主動式功率因數修正控制器雛型電路的功率因數，實驗量測結果符合功率因數達99.5%，符合理論與實作吻合之驗證。

關鍵字：功率因數修正器、輸入電流波形失真、返馳式轉換器

During gasoline upswing, how to economize on power energy is an essential works, that we can work on how to improve power efficient; add the power factor corrector within input and output, harmonics of input current inject reduction are good ideals.
Within this thesis, the power circuit of a fly-back converter and the controller of power factor corrector (PFC) are based on the L6561 IC to implemented. The system is a wide input range voltage (85~265V), fixed duty, variable frequency, high power factor and stable output voltage (24V). Various boost-buck fly-back PFC topologies and several control schemes are discussed and explained in this thesis. Among them, the fly-back topology is chosen, and using the average current control method. L6561 I.C. is widely used in power factor correction circuit. The design procedures of the system are thoroughly explained.
Final, we implemented a 100Watts Fly-back PFC converter satisfy experimental results to confirm the validity and feasibility. Also potential future works are mentioned to further improve the performance and output power of the Fly-back PFC converter.

Keywords: PFC, flyback converter, L6561 IC, average current control

[1] Mohan,Undeland.Robbin 著，江炫樟編譯，“電力電子學”，第二版，民國87年 ，全華科技圖書。
[2] 溫坤禮、陳德超編譯, "最新交換式電源技術",全華科技圖書 Pages: 2-3~2-20。
[3] “L6561, Power Factor Corrector,” ST Product Specification, June 2004.
[4] 吳財福、余德鴻、劉原全著, "單級高功因電子安定器”,全華科技圖書 Pages: 4-3~4-27.
[5] Claudio Adragna, “DESIGN EQUATIONS OF HIGH-POWER-FACTOR FLY-BACK CONVERTERS BASED ON THE L6561”, ST Application Note AN1059, September 2003.
[4] Claudio Adragna, “L6561, Enhanced Transition mode Power Factor Corrector”, ST Application Note AN966, March 2003.
[6] "Flyback Converters with the L6561 PFC Controller", ST Application Note AN1060,September 1998.
[7] Claudio Adragna, “CONTROL LOOP MODELING OF L6561-BASED TM PFC”, ST Application Note AN1089, March 2000.
[8] Cliff Ortmeyer & Claudio Adragna, “DESIGN TIPS FOR L6561 POWER FACTOR CORRECTOR IN WIDE RANGE”, ST Application Note AN1214, December 2000.
[9] International Rectifier, AN1024 “Flyback Transformer Design for the IRIS40xx Series”
[10] Texas Instruments Incorporated, “Understanding Buck-Boost Power Stages in Switchmode Power Supplies”, March 1999.
[11] 宋自恆、林慶仁”功率因數修正電路之原理與常用元件規格”，新電子科技雜誌第217期，2004年4月號。
[12] 簡章華 著“轉換式電源供給器設計技術”民國，88年3月二版9刷
，全華書局，台北
[13] Robert Mammano, John Radovsky and George Harlan ”A New Linear Regulator Features Switch Mode Overcurrent Protection”, IEEE 1989 p159-p164
[14] Daniel W. Hart 著，王順忠譯， “電力電子學”，民國89年2月初版三刷，台北，東華書局。
[15] 楊馨傑,"液晶電視400W交/直流電源模組之研製",中華民國96年1月，國立台灣科技大學碩士學位論文。
[16] 劉建宏,”高效率低空載損耗之200W穩壓器研製”, 中華民國96年6月，國立台灣科技大學碩士學位論文。
[17] 羅永志," 以UC3854實現半橋式功率因數修正器之控制電路",中華民國92年 6月，國立台灣科技大學碩士學位論文。
[18] 鄭振東，”交換式電源手冊”，全華圖書，台北，90年12月初版一刷。