Abstract：This paper presents the derivations and analysis of doubly-fed induction generator’s model under grid voltage unbalance conditions. Active power, reactive power and generator torque are also defined under these conditions. Based on these analysis, an improved control strategy of doubly-fed generator (DFIG) under unbalance conditions is proposed. According to different control purposes, pulsation of stator current, rotor current, active and reactive power, electromagnetic torque can be eliminated by using proposed control scheme. In addition, a fast decomposition algorithm is used to decompose positive and negative sequence and it is much faster than decomposition method based on low pass filter or band pass filter, so the performance of control system is greatly improved. In order to validate the proposed strategy, simulation using Matlab/Simulink and experimental test are carried out and the simulative and experimental results validate the proposed control strategy.
胡胜, 林新春, 康勇, 邹旭东. 一种双馈风力发电机在电网电压不平衡条件下的改进控制策略[J]. 电工技术学报, 2011, 26(7): 21-29.
Hu Sheng, Lin Xinchun, Kang Yong, Zou Xudong. An Improved Control Strategy of Doubly-Fed Induction Generator Under Grid Voltage Unbalance. Transactions of China Electrotechnical Society, 2011, 26(7): 21-29.
[1] Kasem A H, El-Saadany E F, El-Tamaly H H, et al. A new fault ride-through strategy for doubly fed wind-power induction generator[C]. 2007 IEEE Canada Electrical Power Conference, EPC 2007: 1-7. [2] J Lopez, E Guba, P Sanchis, et al. Ride through of wind turbines with doubly fed induction generator under symmetrical voltage dips[J]. IEEE Transactions Industrial Electronics, 2009, 56(10): 4246-4254. [3] Xu L, Wang Y. Dynamic modeling and control of DFIG based windturbines under unbalanced network conditions[J]. IEEE Transactions Power Systems, 2007, 22(1): 314-323. [4] Xu L. Coordinated control of DFIG’s rotor and grid side converters during network unbalance[J]. IEEE Transactions Power Electronic, 2008, 23(3): 1041- 1049. [5] Brekken T K, Mohan N. Control of a doubly fed induction wind generator under unbalanced grid voltage conditions[J]. IEEE Transactions Energy Conversion, 2007, 22(1): 129-135. [6] Codd I. Windfarm power quality monitoring and output comparison with EN50160[C]. Proc. 4th Int. Workshop Large-Scale Integration Wind Power Transmission Networks Offshore Wind Farm, Sweden, Oct. 20-21, 2003. [7] Flannery P S, Venkataramanan G A. Fault tolerant doubly fed induction generator wind turbine using a parallel grid side rectifier and series grid side converter[J]. IEEE Transactions on Power Electronics, 2008, 23(3): 1126-1135. [8] Hochgraf C, Lasseter R H. STATCOM controls for operation with unbalanced voltage[J]. IEEE Transactions Power Delivery, 1998, 13(2): 538-544. [9] Hu Jiabing, He Yikang, Xu Lie. Improved rotor current control of wind turbine driven doubly-fed induction generators during network voltage unbalance[J]. Electric Power Systems Research, 2010, 80(7): 847-856. [10] Hu Jiabing, He Yikang, Xu Lie, et al. Improved control of DFIG systems during network unbalance using PI-R current regulators[J]. IEEE Transactions Industry Electronic, 2009, 56(2): 439-450. [11] Pena R, Cardenas R, Escobar E, et al. Control strategy for a doubly-fed induction generator feeding an unbalanced grid or stand-alone load[J]. Electric Power Systems Research, 2009, 79(2): 355-364. [12] Hu Jiabing, Wang Hongsheng, He Yikang, et al. Improved rotor current control of wind turbine driven doubly fed induction generators during network unbalance[C]. 2009 International Conference on Sustainable Power Generation and Supply, SUPERGEN 2009. [13] 赵阳, 邹旭东, 丁稳房. 不平衡电网电压下并网型双馈感应发电机励磁控制策略[J]. 武汉大学学报(工学版), 2009, 42(1): 110-113. [14] Xu Lie. Enhanced control and operation of DFIG- based wind farms during network unbalance[J]. IEEE Transactions on Energy Conversion, 2008, 23(4): 1073-1081. [15] Liang Yiqiao. A new time domain positive and negative sequence component decomposition algorithm[C]. 2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491), 2003, 3: 1638-1643. [16] De Souza H E P, Bradaschia F, Neves F A S, et al. A method for extracting the fundamental-frequency positive-sequence voltage vector based on simple mathematical transformations[J]. IEEE Transactions Industrial Electronics, 2009, 56(5): 1539-1547.
2011, Vol. 26 
