近年來風力發電採用永磁發電機越趨普及，永磁式同步發電機需全額定轉換器。由於轉換器的額定功率越來越大，風力發電機大部份時間卻操作在低風速下，並聯多組整流器取代單一整流器可以選用較低電流應力的開關元件並提升低風速時的轉換效率。然而其缺點是整流器並聯時會產生循環電流(環流)導致電流失真。針對抑制循環電流部份本文推導出發電機、零相序阻抗及並聯三相脈寬調變整流器之數學模型，並設計出適當的電流控制器以抑制循環電流。另外，本論文亦採用新型適應性追蹤演算法與電流分配策略，相較於傳統擾動觀察法，其動作分析較為簡單且可由電氣回授信號判斷風速變動。最後應用在風電轉換器中，並以風渦輪機模擬器驗證環流抑制及最大功率追蹤演算法之效果。

In recent years, permanent magnetic synchronous generator (PMSG) has been widely used in the wind power generation. A PMSG needs full-rated power converter to convert wind energy into electrical energy. Due to the increasing trend of power rating on the power converter; the power converter, however, usually operates at low wind speed. Paralleling PWM rectifiers to replace a full-rated power converter can reduce current stress of the converter and improve converter’s efficiency at low wind speed. However, paralleling PWM rectifiers may cause circulating current and distort the current waveform. In order to suppress circulating current, this thesis derives three phase rectifier model which includes generator, zero sequence impedance, and design a current controller accordingly. In addition, this research adopts a novel adaptive maximum power point tracking algorithm with current distribution strategy for the paralleling PWM rectifier. In contrast to traditional perturb and observe method, novel adaptive MPPT algorithm can be easily analyzed and determine wind change by feedback signal. The effectiveness of the circulating current suppression and maximum power tracking efficiency are verified by a wind turbine emulator.

[1]2012年能源產業技術白皮書, 經濟部能源局, 2012.
[2]World Wind Energy Report 2012, WWEA, 2012.
[3]World Wind Energy Half-year Report 2013, WWEA, 2013.
[4]發電資訊-我國再生能源發電現況, 臺灣電力公司 Available: http://www.taipower.com.tw/content/new_info/new_info-b31.aspx?LinkID=8
[5]梁威志, “新型適應性最大功率追蹤演算法之三相風能轉換系統,”國立成功大學電機工程學系碩士論文, 2012年6月.
[6]H. C. Lu and L. R. Chang-Chien, “Use of wind turbine emulator for the WECS development,” Power Electronics Conference (IPEC), 2010 International, pp. 3188-3195, June 2010.
[7]K. Zhou and D. Wang, “Relationship between space-vector modulation and three-phase carrier-based PWM: a comprehensive analysis,” IEEE Trans. Ind. Electron., vol. 49, no. 1, pp. 186-196, Feb. 2002.
[8]王國丞, “並聯型三相不斷電系統之研製,” 國立臺灣科技大學電機工程學系碩士論文, 2006年6月.
[9]C. M. Ong, Dynamic Simulation of Electric Machinery: Using MATLAB/SIMULINK. Taiwan: Pearson Education, 2003.
[10]B. K. Bose, Modern Power Electronics and AC Drives. USA: Prentice Hall, 2001.
[11]B. Yin, R. Oruganti, S. K. Panda, and A. K. S. Bhat, “A simple single –input-single-output (SISO) model for a three-phase PWM rectifier,” IEEE Trans. Power Electron., vol. 24, pp. 620-631, Mar. 2009.
[12]B. H. Bae, S. K.Sul, J. H. Kwon, and J. S. Byeon, “Implementation of sensorless vector control for super-high-speed PMSM of turbo-compressor,” IEEE Trans. Ind. Appl., vol. 39, no. 3,pp. 811-818, May/June 2003.
[13]C. T. Pan and Y. H. Liao, “Modeling and control of circulating currents for parallel three-phase boost rectifiers with different load sharing,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2776-2785, Jul. 2008.
[14]江智弘, “兩並聯整流器間循環電流之抑制研究”, 國立成功大學電機工程學系碩士論文, 2013年6月.
[15]T. Kawabata and S. Higashino, “Parallel operation of voltage source inverters,” IEEE Trans. Ind. Appl., vol. 24, no. 2, pp. 281-287, Mar./Apr. 1988.
[16]S. Ogasawar, H. Akagi, and A. Nabae, “A novel control scheme of a parallel current-controlled PWM inverter,” IEEE Trans. Ind. Appl., vol. 28, no. 5, pp. 1023-1030, Sept./Oct. 1992.
[17]Y. Sato and T. Kataoka, “Simplified control strategy to improve ac-input-current waveform of parallel-connected current-type PWM rectifiers,” in Proc. Inst. Elect., vol.142, pp. 246-254, July 1995.
[18]C. T. Pan and Y. H. Liao, “Modeling and coordinate control of circulating currents in parallel three-phase boost rectifiers,” IEEE Trans. Ind. Electron., vol. 54, no. 2, pp. 825-838, Apr. 2007.
[19]R. Li and D. G. Xu, “Parallel operation of full power converters in permanent-magnet direct-drive wind power generation system,” IEEE Trans. Ind. Appl., vol. 60, no. 4, pp. 1619-1629, Apr. 2013.
[20]Z. Xu, R. Li, and D. G. Xu, “Control of parallel multirectifiers for a direct-drive permanent-magnet wind power generator,” IEEE Trans. Ind. Appl., vol. 49, no. 4, pp. 1687-1696, July/Aug. 2013.
[21]桂人傑, “變速風機之控制系統,” 機械工程,第261期,第20-36頁, 2007年6月.
[22]K. Tan and S. Islam, “Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors,” IEEE Trans. Energy Convers., vol. 19, no. 2, pp.392-399, Jun. 2004.
[23]F. Valenciaga and P. F. Puleston, “Supervisor control for a stand-alone hybrid generation system using wind and photovoltaic energy,” IEEE Trans. Energy Convers., vol. 20, no. 2, pp.398-405, Jun. 2005.
[24]M. Chinchilla, S. Arnaltes, and J.C. Burgos, “Control of permanent-magnet generators applied to variable-speed wind energy systems connected to the grid,” IEEE Trans. Energy Convers., vol.21, no. 1, pp.130-135, Mar.2006.
[25]E. Koutroulis and K. Kalaitzakis, “Design of a maximum power tracking system for wind-energy-conversion applications,” IEEE Ind. Electron., vol. 53, no. 2, pp. 486-494, Apr. 2006.
[26]S. M. R. Kazmi, H. Goto, H.-J. Guo, and O. Ichinokura, “A novel algorithm for fast and efficient speed-sensorless maximum power point tracking in wind energy conversion systems,” IEEE Trans. Ind. Electron., vol.58, no. 2,pp. 29-36, Jan. 2011.
[27]Y. Xia, K. H. Ahmed, and B. W. Williams, “A new maximum power point tracking technique for permanent magnet synchronous generator based energy conversion system,” IEEE Trans. Power Electron., vol. 26, no. 12, pp. 3609-3620, Dec. 2011.
[28]曾百由, dsPIC數位訊號控制器原理與應用-MPLAB C30開發實務.台北市: 宏友圖書開發股份有限公司, 2009.
[29]“能源國家型計畫研究計畫-高效能中小型(10千瓦)風力發電機之系統開發與性能驗證,” 行政院國家科學委員會, 計畫編號:NSC 100-3113-E-006-005, 2010.