近年來由於小型風力發電、屋頂式太陽能電池等小型電源的普及，使小型電源所組成的微電網形成一種新興的趨勢。小型電源所組成的微電網位於電力系統的配電端，電壓層級相當低，傳輸線同時存在電感性與電阻性兩種阻抗特性。根據純電感性阻抗傳輸線功率潮流方程式，使用傳統實功-頻率、虛功-電壓下降控制器會造成大量的虛功在反流器間流動，造成不必要的線路損失。將功率潮流方程式考慮電阻性成分後，使用傳輸線阻抗矩陣雖然可以轉換實功與虛功，使下降控制器符合傳輸線電感-電阻比，但傳輸線的特性卻會隨時間改變，且電壓下降控制器因傳輸線電壓降所產生的功率分配誤差仍然有很大的改善的空間。
為了使傳輸線阻抗矩陣依照系統狀態自動改變且不需要預先設定與系統相關的參數，因此本文提出一個最小輸出電流追蹤控制器，此控制器會根據輸出電流的變化量來改變下降控制器阻抗矩陣的旋轉角度，使反流器依照系統負載、傳輸線特性，在沒有任何通信界面下輸出最小電流，避免不必要的電流在傳輸線中流動，提升反流器整體效能。
本文同時驗證頻率重建控制器與負序虛功-導納下降控制器在電阻性傳輸線下，該控制器是否能正常運作，並使用簡單的分流電路來分析不同的電感-電阻比傳輸線對負序虛功-導納下降控制器分配負序虛功的影響。
為了驗證所提出的控制器，相關的模擬與實驗平台將會在此論文中架設並進一步的分析討論。

[1] Vu Van Thong, Johan Driesen, Ronnie Belmans, " Benefits and Impact of Using Small Generators for Network Support ", Power Engineering Society General Meeting, 2007. IEEE, p.p. 1-7, 2007.

[2] P. Piagi, R. H. Lasseter ," Autonomous Control of Microgrids ", Power Engineering Society General Meeting, 2006. IEEE, p.p. 1-8 , 2006.

[3]Tzung-Lin Lee, Po-Tai Cheng, " Design of a New Cooperative Harmonic Filtering Strategy for Distributed Generation Interface Converters in an Islanding Network ", IEEE Transactions on Power Electronics, vol.22 , p.p. 1919-1927 ,2007.

[4] Po-Tai Cheng, Chien-An Chen, Tzung-Lin Lee, Shen-Yuan Kuo, "A Cooperative Unbalance Compensation Method for Distributed Generation Interface Converters ", Industry Applications Conference, 2007. 42nd IAS Annual Meeting. Conference Record of the 2007 IEEE, p.p. 1567-1573 ,2007.

[5] K. De Brabandere, K. Vanthournout, J. Driesen, G. Deconinck, R. Belmans , "Control of Microgrids ", Power Engineering Society General Meeting, 2007. IEEE, p.p. 1-7 ,2007.

[6] F. Katiraei, M. R. Iravani, " Power Management Strategies for a Microgrid with Multiple Distributed Generation Units ", IEEE Transactions on Power Systems, vol.21 , p.p. 1821-1831 ,2006.

[7] M. N. Marwali, Jin-Woo Jung, A. Keyhani, " Stability Analysis of Load Sharing Control for Distributed Generation Systems " IEEE Transaction on Energy Conversion, vol.22 , p.p. 737-745 ,2007.

[8] M. C. Chandrokar, D. M. Divan, B. Banerjee, " Control of Distributed UPS Systems ", Power Engineering Society General Meeting. IEEE, vol.1 , p.p. 197-204 ,1994.
[9] N. L. Soultanis, N. D. Hatziargyriou, " Control Issues of Inverters in the Formation of L. V. Micro-grids ", Power Engineering Society General Meeting, 2007. IEEE, p.p. 1-7 ,2007.

[10] A. Engler, N. Soultanis, " Droop Control in LV-Grids ", 2005 International Conference on Future Power Systems, p.p. 1-6 ,2005.

[11] H. Laaksonen, P. Saari, R. Komulainen, " Voltage and Frequency Control of Inverter Based Weak LV Network Microgrid ", 2005 International Conference on Future Power Systems, p.p. 6 ,2005.

[12] Josep M. Guerrero, Nestor Berbel, Jose Matas, Luis Garcia de Vicuna, Jaume Miret," Decentralized Control for Parallel Operation of Distributed Generation Inverters in Microgrids Using Resistive Output Impedance ", IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics, p.p. 5149-5154 ,2006.

[13] P. N. Vovos, A. E. Kiprakis, A. R. Wallace, G. P. Harrison, "Centralized and Distributed Voltage Control: Impact on Distributed Generation Penetration ", IEEE Transactions on Power Systems, vol.22 , p.p. 476-483 ,2007.

[14] K. De Brabandere, B. Bolsens, J. Van den Keybus, A. Woyte, J. Driesen, R. Belmans, K. U. Leuven, "A Voltage and Frequency Droop Control Method for Parallel Inverters ", IEEE Transactions on Power Electronics, vol.22 , p.p. 1107-1115 ,2007.

[15] A. E. Emanuel, "On the Definition of Power Factor and Apparent Power in Unbalanced Polyphase Circuits with Sinusoidal Voltage and Currents", IEEE Transactions on Power Delivery, vol. 8, p.p. 841-852 , 1993.

[16] J. L. Afonso, M. J. S. Freitas, J. S. Martins, "p-q Theory Power Components Calculations", IEEE International Symposium on Industrial Electronics, vol. 1, p.p. 385-390, 2003.

[17] R. W. De Doncker, J. P. Lyons, "Control of Three Phase Power Supplies for Ultra Low THD", APEC '91. Conference Proceedings, p.p. 622-629, 1991.

[18] M. C. Chandorkar, D. M. Divan, R. Adapa, "Control of Parallel Connected Inverters in Standalone AC Supply Systems", IEEE Transactions on Industry Applications, vol. 29, p.p. 136-143, 1993.