近幾年來，電壓驟降在工業界已成為一個非常重要的議題。主要的原因在於配電系統中的電壓驟降事故，常會導致重要的負載因欠電壓保護而中斷。而傳統的橋式整流二極體在使用上，常會因為市電電壓的降低，使得其直流側，因欠電壓的影響，造成操作中斷。因為主動前端轉換器除了具有單位功率因數控制之外，並且能允許直流側能量回復至交流市電端之雙向電力潮流控制，在現今的工業界中，使用電晶體的主動前端轉換器已經越來越受到歡迎。再者，主動式前端轉換器還具有控制直流側電壓的能力，當電壓驟降發生時，將電壓回升至合理的範圍。其電壓驟降渡過的能力，可以防止重要的負載操作中斷。
在近期，有一種輔助式轉換器的架構被提出來，這個輔助式的轉換器和橋式整流二極體並聯在一起。這個新提出的轉換器架構也具有諧波補償及能量回升的能力，整個系統和傳統的前端轉換器有相同的功能，但是系統容量卻可以小於傳統的前端轉換器一半。由此，輔助式的轉換器低成本的優點就顯而易見。在本文中，將提出輔助式轉換器在電壓驟降下渡過的能力，同時建立其動態模型來評估控制器的設計。在實驗室的測試結果，將用來驗輔助式轉換器的功能、效能及動態模型的正確性。

In recent years, voltage sag has become a very serious problem in industry because critical loads are often interrupted. The conventional diode rectifier often suffers from the reduced grid voltages and the resultant under-voltage alarm on its DC link could interrupt the operation. An auxiliary converter, connected in parallel with the diode rectifier on both the DC side and the AC side, is proposed. The auxiliary converter provides harmonic current compensation by active filter control and regeneration capability, thus the over-all system has the same functionalities as the conventional active front-end converter. The auxiliary converter can accomplish these functionalities with less than 0.5pu capacity compared to the more than 1.0 pu active front-end converter, thus its cost advantage is obvious. In this paper, a voltage sag ride-through solution is proposed for the auxiliary converter. Its controller design is presented, and its dynamic model is also established to evaluate the control design. Laboratory test results are presented to validate the proposed circuit and its performance.

[1]Chung-Chuan Hou and Po-Tai Cheng, "An Auxiliary Converter for a Diode Rectifier with Mitigated Circulating Current," in Industry Applications Conference, 2007. 42nd IAS Annual Meeting. Conference Record of the 2007 IEEE, 2007, pp. 1601-1607.
[2]Po-Tai Cheng, Chung-Chuan Hou, and Jian-Shen Li, "Design of an Auxiliary Converter for the Diode Rectifier and the Analysis of the Circulating Current," in Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE, 2006, pp. 1-7.
[3]Chung-Chuan Hou, Po-Tai Cheng, Subhashish Bhattacharya, and Jarsun Lin, "Modeling and Control of Three-Phase Active front-end Converters," in Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE, 2007, pp. 1449-1454.
[4]Hong-seok Song and Kwanghee Nam, "Dual current control scheme for PWM converter under unbalanced input voltage conditions," IEEE Transactions on Industrial Electronics, vol. 46, pp. 953-959, 1999.
[5]Yongsug Suh and Thomas A. Lipo, "Control scheme in hybrid synchronous stationary frame for PWM AC/DC converter under generalized unbalanced operating conditions," IEEE Transactions on Industry Applications, vol. 42, pp. 825-835, 2006.
[6]Van E Wagner, Allen A. Andreshak, and Joseph P. Staniak, "Power quality and factory automation," IEEE Transactions on Industry Applications, vol. 26, pp. 620-626, 1990.
[7]Jos´e Luis Dur´an-G´omez, Prasad N. Enjeti, and Byeong Ok Woo, "Effect of voltage sags on adjustable-speed drives: a critical evaluation and an approach to improve performance," IEEE Transactions on Industry Applications, vol. 35, pp. 1440-1449, 1999.
[8]Fang Zheng Peng, "Application issues of active power filters," IEEE Industry Applications Magazine, vol. 4, pp. 21-30, 1998.
[9]Subhashish Bhattacharya and Deepak Divan, "Active filter solutions for utility interface of industrial loads," in Power Electronics, Drives and Energy Systems for Industrial Growth, 1996., Proceedings of the 1996 International Conference on, 1996, pp. 1078-1084 vol.2.
[10]Gil Marques, "A comparison of active power filter control methods in unbalanced and non-sinusoidal conditions," in Industrial Electronics Society, 1998. IECON '98. Proceedings of the 24th Annual Conference of the IEEE, 1998, pp. 444-449 vol.1.
[11]Yongsug Suh and Thomas A. Lipo, "Modeling and analysis of instantaneous active and reactive power for PWM AC/DC converter under generalized unbalanced network," IEEE Transactions on Power Delivery, vol. 21, pp. 1530-1540, 2006.
[12]Hirofumi Akagi, "Control strategy of Active Power filters Using Multiple Voltage-Source PWM Converter," IEEE Transactions on Industry Applications, vol. IA-22, pp. 460-465, 1986.
[13]Ashish Bendre, Deepak Divan, William Kranz, and William Brumsickle, "Are voltage sags destroying equipment?," IEEE Industry Applications Magazine, vol. 12, pp. 12-21, 2006.
[14]William E. Brumsickle, Robert S. Schneider, Glen A. Luckjiff, Deepak M. Divan, and Mark F. McGranaghan,"Dynamic sag correctors: cost-effective industrial power line conditioning," IEEE Transactions on Industry Applications, vol. 37, pp. 212-217, 2001.
[15]William E. Brumsickle, Deepak M. Divan, Glen A. Luckjiff, John W. Freeborg, and Roger L. Hayes, "Operational experience with a nationwide power quality and reliability monitoring system," in Industry Applications Conference, 2003. 38th IAS Annual Meeting. Conference Record of the, 2003, pp. 1063-1067 vol.2.
[16]Yasuhiro Komatsu and Takao Kawabata, "A control method of active power filter in unsymmetrical voltage system," in Power Electronics and Drive Systems, 1997. Proceedings., 1997 International Conference on, 1997, pp. 839-843 vol.2.
[17]Bin Shi, Giri Venkataramanan and Naresh Sharma, “Design considerations for reactive elements and control parameters for three phase boost rectifiers,” in Electric Machines and Drives, IEEE International Conference, 15 May 2005, pp. 1757–1764.
[18]Semiconductor Equipment and Materials International (SEMI) Starndards SEMI F47-0706 “Specification for Semiconductor Processing Equipment Voltage Sag Immunity”. 2006.
[19]International Electrotechnical Commission standard IEC 61000-4-11 “Testing and measurement techniques –Voltage dips, short interruptions and voltage variations immunity tests”, 2004..
[20]International Electrotechnical Commission standard IEC 61000-4-34 “Testing and measurement techniques –Voltage dips, short interruptions and voltage variations immunity tests for equipment with input current more than 16 A per phase” 2005.
[21]Yogsug Suh, Valentin Tijeras, and Thomas A. Lipo, "A nonlinear control of the instantaneous power in dq synchronous frame for PWM AC/DC converter under generalized unbalanced operating conditions," in Industry Applications Conference, 2002. 37th IAS Annual Meeting. Conference Record of the, 2002, pp. 1189-1196 vol.2.