微电网孤岛工况下基于四桥臂变流器的不平衡负载分配策略

Abstract
Figure/Table
References
Related Citation (15)

Download: PDF (1321 KB) HTML (1 KB)
Export: BibTeX | EndNote (RIS)

Abstract The active power-frequency, reactive power-voltage based droop control is widely used in microgrids to share the load powers among converters. The conventional droop control method has not guaranteed the unbalance current sharing accuracy. To overcome the drawback above, the three-phase four-leg topology is adopted as a microgrid converter. The principle of unbalanced load current sharing and the causes of zero sequence circulating current are investigated. A negative and zero sequence virtual impedance based load sharing method is proposed in this paper, and it is integrated with positive sequence power droop controller. The negative and zero sequence currents are sharing reasonably according to virtual impedances in each sequence, which mitigate the effect of line impedance mismatch. Finally, the proposed control strategy is verified on a four-leg paralleled converters test rig. The experimental results show that the four-leg converters with the proposed method are operating stably in parallel and not only the unbalanced currents are sharing accurately, but also the zero sequence circulating current is suppressed effectively.

Key words： Microgrid droop control three-phase four-leg unbalanced load virtual impedance

Received: 16 January 2014 Published: 14 September 2015

PACS:

TM464

	Service

	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	Zhou Xiao
	Jin Xinmin
	Tang Fen
	Wu Xuezhi
	Tong Yibin

Cite this article:

Zhou Xiao,Jin Xinmin,Tang Fen等. Four-Leg Converter Based Unbalanced Load Sharing Method in Islanding Microgrid[J]. Transactions of China Electrotechnical Society, 2015, 30(12): 76-86.

URL:

https://dgjsxb.ces-transaction.com/EN/ OR https://dgjsxb.ces-transaction.com/EN/Y2015/V30/I12/76

[1] Rocabert J, Luna A, Blaabjerg F, et al. Control of power converters in ac microgrids[J]. Power Electronics, IEEE Transactions on, 2012, 27(11): 4734-4749.
[2] 王成山, 肖朝霞, 王守相. 微电网中分布式电源逆变器的多环反馈控制策略[J]. 电工技术学报, 2009, 24(2): 100-107. Wang Chengshan, Xiao Zhaoxia, Wang Shouxiang. Multiple feedback loop control scheme for inverters of the micro source in microgrids[J]. Transactions of China Electrotechnical Society, 2009, 24(2): 100-107.
[3] 黄杏, 金新民. 微电网用分布式电源变流器下垂特性控制策略[J]. 电工技术学报, 2012, 27(8): 93-100. Huang Xing, Jin Xinmin. A voltage and frequency droop control method for microsources[J]. Transactions of China Electrotechnical Society, 2012, 27(8): 93- 100.
[4] He J W, Li Y W, Munir M S. A flexible harmonic control approach through voltage-controlled DG-grid interfacing converters[J]. Industrial Electronics, IEEE Transactions on, 2012, 59(1): 444-455.
[5] Wang X F, Blaabjerg F, Zhe Chen. An improved design of virtual output impedance loop for droop- controlled parallel three-phase voltage source inverters [C]. Energy Conversion Congress and Exposition (ECCE), 2012 IEEE, Raleigh, NC, 2012: 2466-2473.
[6] Cheng Po-Tai, Chen Chien-An, Lee Tzung-Lin, et al. A cooperative imbalance compensation method for distributed-generation interface converters[J]. Industry Applications, IEEE Transactions on, 2009, 45(2): 805-815.
[7] Savaghebi M, Jalilian A, Vasquez J C, et al. Auto- nomous voltage unbalance compensation in an islanded droop-controlled microgrid[J]. Industrial Electronics, IEEE Transactions on, 2013, 60(4): 1390-1402.
[8] De D, Ramanarayanan V. Decentralized parallel opera- tion of inverters sharing unbalanced and nonlinear loads [J]. Power Electronics, IEEE Transactions on, 2010, 25(12): 3015-3025.
[9] 张佳佳, 石东源. 分布式电源用四桥臂变换器中点电压漂移控制[J]. 电工技术学报, 2013, 28(2): 225-232. Zhang Jiajia, Shi Dongyuan. Control of neutral point voltage shift for four-leg converter in distributed generation[J]. Transactions of China Electrotechnical Society, 2013, 28(2): 225-232.
[10] 孙驰, 鲁军勇, 马伟明. 一种新的三相四桥臂逆变器控制方法[J]. 电工技术学报, 2007, 22(2): 57-63. Sun Chi, Lu Junyong, Ma Weiming. A novel control method for three-phase four-leg inverter[J]. Transactions of China Electrotechnical Society, 2007, 22(2): 57-63.
[11] Guerrero J M, Garcia De Vicuna L, Matas J, et al. Output impedance design of parallel-connected UPS inverters with wireless load-sharing control[J]. Industrial Electronics, IEEE Transactions on, 2005, 52(4): 1126-1135.
[12] Zhang R. High performance power converter systems for nonlinear and unbalanced load/source[D]. Blacks- burg: Virginia Polytechnic Institute and State Univer- sity, 1998.
[13] 张兴, 陈玲, 杨淑英, 等. 离网型小型风力发电系统逆变器的控制[J]. 电力系统自动化, 2008, 32(23): 95-99. Zhang Xing, Chen Ling, Yang Shuying, et al. Inverter control of an isolated small scale wind power genera- tion system[J]. Automation of Electric Power Systems, 2008, 32(23): 95-99.
[14] 王先为, 卓放. 三相四桥臂并联逆变器的零序电流建模与控制[J]. 西安交通大学学报, 2012, 46(10): 8-14. Wang Xianwei, Zhuo Fang. Modeling and control of zero sequence current in paralleled three-phase four-leg inverter[J]. Journal of Xian Jiaotong University, 2012, 46(10): 8-14.
[15] Rodriguez P, Timbus A V, Teodorescu R, et al. Flexible active power control of distributed power generation systems during grid faults[J]. Industrial Electronics, IEEE Transactions on, 2007, 54(5): 2583- 2592.
[16] He J W, Li W Y. Analysis, design, and implementation of virtual impedance for power electronics interfaced distributed generation[J]. Industry Applications, IEEE Transactions on, 2011, 47(6): 2525-2538.
[17] 关雅娟, 邬伟扬, 郭小强. 微电网中三相逆变器孤岛运行控制技术[J]. 中国电机工程学报, 2011, 31(33): 52-60. Guan Yajuan, Wu Weiyang, Guo Xiaoqiang. Control strategy for three-phase inverters dominated microgrid in autonomous operation[J]. Proceedings of the CSEE, 2011, 31(33): 52-60.
[18] 吴睿, 谢少军. 基于abc坐标系空间矢量控制的三相四桥臂电压源型逆变器研究[J]. 电工技术学报, 2005, 20(12): 47-52. Wu Rui, Xie Shaojun. Research on the four-leg voltage source inverters based on space vector modulation in abc coordinates[J]. Transactions of China Electro- technical Society, 2005, 20(12): 47-52.