An Improved Droop Control Method for Voltage and Frequency Restoration in Microgrid

doi:10.3969/j.issn.1000－7229.2016.10.007

Abstract

Abstract: At present, the realization of the island microgrid control is generally based on droop control. The droop control can not only ensure the stabilities of voltage and frequency, and realize the reasonable load sharing of distributed generation. But for the high demand of power quality, there will normally be the recovery control of the voltage and frequency for the second time after droop control, which results in the increase of operating costs. In view of this problem, this paper proposes a method based on the ‘washing and filtering’ to restore the voltage and frequency after the analysis of the droop control principle. This method introduces a ‘washing and filtering’ controller before droop control, which can restore the voltage and frequency without increasing the secondary communication line. Through the simulation experiment in PSCAD/EMTDC software platform, the results show that this method can recover the voltage drop and the frequency deviation after the load change of microgrid.

Key words: island microgrid, droop control, washing and filtering

CLC Number:

TM 711

ZHANG Xinzhou, WANG Weiqing, WANG Haiyun. An Improved Droop Control Method for Voltage and Frequency Restoration in Microgrid[J]. Electric Power Construction, 2016, 37(10): 48-.

References

［1］刘强, 周林, 郭珂. 微电网的动态特性及控制策略分析［J］. 电力建设, 2014, 35(6):31-37. LIU Qiang, ZHOU Lin, GUO Ke. Analysis on the dynamic characteristics and control method of microgrid［J］. Electric Power Construction, 2014, 35(6):31-37. ［2］王杨,万凌云,胡博,等. 基于孤岛运行特性的微电网可靠性分析［J］. 电网技术, 2014, 38(9): 2379-2385. WANG Yang, WAN Lingyun, HU Bo, et al. Isolated island operating characteristics based analysis on reliability of microgrid［J］. Power System Technology, 2014, 38(9): 2379-2385. ［3］宋洪磊, 李晓飞, 吴俊勇,等. 解列后电力孤岛的校正控制策略研究［J］. 电力建设, 2016, 37(4):124-130. SONG Honglei, LI Xiaofei, WU Junyong, et al. Correction control strategy of islanded power grid after separation［J］. Electric Power Construction, 2016, 37(4): 124-130. ［4］王波, 张保会, 郝治国. 基于功率监测和频率变化率的孤岛微电网紧急切负荷控制［J］. 电力系统自动化, 2015, 39(8): 33-37. WANG Bo, ZHANG Baohui, HAO Zhiguo. Emergency load shedding control for islanded microgrid based on power monitoring and rate of frequency change［J］. Automation of Electric Power Systems, 2015, 39(8): 33-37. ［5］鲍薇, 胡学浩, 李光辉,等. 基于同步电压源的微电网分层控制策略设计［J］. 电力系统自动化, 2013, 37(23): 20-26. BAO Wei, HU Xuehao, LI Guanghui, et al. Synchronous voltage source based design of hierarchical control strategy for microgrid［J］. Automation of Electric Power Systems, 2013, 37(23): 20-26. ［6］孙孝峰, 杨雅麟, 赵巍, 等. 微电网逆变器自适应下垂控制策略［J］. 电网技术, 2014, 38(9): 2386-2391. SUN Xiaofeng, YANG Yalin, ZHAO Wei, et al. An adaptive droop control method for inverters in microgrid［J］. Power System Technology, 2014, 38(9): 2386-2391. ［7］LIANG J, JI Y, WU W, et al. AC/DC hybrid micro grid voltage recovery control［C］//2015 5th International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT). Changsha: IEEE, 2015: 1256-1260. ［8］孙孝峰, 王娟, 田艳军, 等. 基于自调节下垂系数的DG逆变器控制［J］. 中国电机工程学报, 2013, 33(36): 71-78. SUN Xiaofeng, WANG Juan, TIAN Yanjun, et al. Control of DG connected inverters based on self-adaptable adjustment of droop coefficient［J］. Proceedings of the CSEE, 2013, 33(36): 71-78. ［9］张明锐, 杜志超, 黎娜, 等. 高压微网孤岛运行时频率稳定控制策略研究［J］. 中国电机工程学报, 2012, 32(25): 20-26. ZHANG Mingrui, DU Zhichao, LI Na, et al. Control strategies of frequency stability for islanding high-voltage microgrids［J］. Proceedings of the CSEE, 2012, 32(25): 20-26. ［10］李坦, 杨洪耕, 齐少鹏, 等. 基于P/δ下垂控制的低压微电网频率控制策略［J］. 电测与仪表, 2015, 52(7): 66-70. LI Tan，YANG Honggeng，QI Shaopeng, et al. Control strategy for low-voltage microgrid frequency based on P /δ droop control［J］. Electrical Measurement ＆ Instrumentation, 2015, 52(7): 66-70. ［11］吕思卓, 郑超, 杨金刚,等. 送端直流孤岛系统频率限制器优化控制策略［J］. 电力建设, 2016, 37(2): 107-111. LYU Sizhuo, ZHENG Chao, YANG Jingang, et al. FLC optimization control strategy of islanded HVDC sending system［J］. Electric Power Construction, 2016, 37(2): 107-111. ［12］孙孝峰, 吕庆秋. 低压微电网逆变器频率电压协调控制［J］. 电工技术学报, 2012, 27(8): 77-84. SUN Xiaofeng, LYU Qingqiu. Improved PV control of grid-connected inverter in low voltage micro-grid［J］. Transactions of China Electrotechnical Society, 2012, 27(8): 77-84. ［13］成瑞芬, 韩肖清, 王鹏,等. 微电网动态电压恢复器运行模式研究［J］. 电网技术,2013, 37(3):610-615. CHENG Ruifen, HAN Xiaoqing, WANG Peng, et al. Research on operation modes of dynamic voltage restorer in microgrid［J］. Power System Technology, 2013, 37(3):610-615. ［14］NASIRIAN V, SHAFIEE Q, GUERRERO J M, et al. Droop-free team-oriented control for AC distribution systems［C］//2015 IEEE Applied Power Electronics Conference and Exposition (APEC). Charlotte, NC: IEEE, 2015: 2911-2918. ［15］HASSOUNEH M A, LEE H C, ABED E H. Washout filters in feedback control: benefits, limitations and extensions［C］// American Control Conference, 2004. Proceedings of the 2004. Boston, MA, USA: IEEE, 2004: 3950-3955.

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[6]	LI Jiaji1, YU Baoxin1, ZHANG Huadong1, LI Wenlong1, XUE Yushi2, CHU Tiezhu1, BI Ran1. Control Strategy of Distributed Energy Storage in Island Distribution Network [J]. Electric Power Construction, 2018, 39(4): 83-.
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[13]	LI Zishou， ZHOU Mi， XU Jian， LAN Tiankai. An Improved Droop Control Method for VSC-MTDC Considering AC Grid Regulation Ability [J]. Electric Power Construction, 2016, 37(6): 79-85.
[14]	XIE Wenchao，ZHU Yongqiang，DU Shaofei，XIA Ruihua. Power Control of Interlinking Converter in AC/DC Hybrid Microgrid [J]. Electric Power Construction, 2016, 37(10): 9-.
[15]	WANG Kai, SUN Haishun, HU Xiaobo, ZHANG Ke. DC Voltage Control and Power Dispatch Strategy of a Five-Terminal VSC-Based DC Grid [J]. ELECTRIC POWER CONSTRUCTION, 2015, 36(4): 52-58.