含多并联组网DG的微电网分层控制体系及其控制策略
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摘要
基于下垂调节机制的孤立微电网分层控制体系中,底层控制存在电压调节性能和功率分配精度的固有矛盾,在组网分布式电源(distributed generation,DG)运行点变化时易造成母线电压频率、幅值的突变,需要二层控制在更长的时间尺度下对其进行补偿和修正,这将不利于系统的稳定运行。因此,该文提出一种新型的微电网分层控制体系:一层控制采用分散控制的方法,在系统稳态(如线路阻抗不匹配)或动态(如负荷突变、DG投切)情况下,能够同时满足电压调节质量和功率分配精度。引入权重系数以协调各台DG所承担的负荷比例,该权重系数可由二层控制通过分布式的方式计算生成,并且权重系数可在线调节,权重系数的改变并不影响系统电压稳定。所提分层控制动态响应迅速,有利于实现孤立微电网的功率灵活调控和稳定运行。理论分析和硬件在环实验结果均说明了该控制策略的可行性和有效性。
For the droop-based hierarchical control architecture, the primary control has the inherent tradeoff between superior voltage regulation and power sharing accuracy, frequency and amplitude deviation inevitably appears when deals with the operation point variation of the grid-forming distributed generations(DGs). Although the secondary control is commonly installed to avoid these problems in a relatively long time scale, which significantly affects the system stability. This paper proposed a novel hierarchical control architecture: a decentralized primary control was designed for achieving voltage regulation and accurate power sharing simultaneously in both steady-state(e.g., line impedance mismatch) and transient-state(e.g., loads variation, DG plug in/off). Meanwhile, a weight coefficient was introduced for proportional power sharing performance, which could be distributively calculated by the secondary control.Furthermore, the weight coefficient can be changed on-line and has no effect on the voltage regulation. Thus stable and flexible operation of the micro-grid can be ensured. Theoretical analysis and hardware-in-the-loop simulation results verified the effectiveness of the proposed approach.
For the droop-based hierarchical control architecture, the primary control has the inherent tradeoff between superior voltage regulation and power sharing accuracy, frequency and amplitude deviation inevitably appears when deals with the operation point variation of the grid-forming distributed generations(DGs). Although the secondary control is commonly installed to avoid these problems in a relatively long time scale, which significantly affects the system stability. This paper proposed a novel hierarchical control architecture: a decentralized primary control was designed for achieving voltage regulation and accurate power sharing simultaneously in both steady-state(e.g., line impedance mismatch) and transient-state(e.g., loads variation, DG plug in/off). Meanwhile, a weight coefficient was introduced for proportional power sharing performance, which could be distributively calculated by the secondary control.Furthermore, the weight coefficient can be changed on-line and has no effect on the voltage regulation. Thus stable and flexible operation of the micro-grid can be ensured. Theoretical analysis and hardware-in-the-loop simulation results verified the effectiveness of the proposed approach.
引文
[1]鲁宗相,王彩霞,闵勇,等.微电网研究综述[J].电力系统自动化,2007,31(19):100-107.Lu Zongxiang,Wang Caixia,Min Yong,et al.Overviewon micro-grid research[J].Automation of Electric Power Systems,2007,31(19):100-107(in Chinese).
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[9]余志文,艾芊,熊文.基于多智能体一致性协议的微电网分层分布实时优化策略[J].电力系统自动化,2017,41(18):25-33.Yu Zhiwen,Ai Qian,Xiong Wen.Hierarchical distributed real-time optimization strategy for micro-grid based on consistency protocol of multi-agent system[J].Automation of Electric Power Systems,2017,41(18):25-33(in Chinese).
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[13]周烨,汪可友,李国杰.基于多智能体一致性算法的微电网分布式分层控制策略[J].电力系统自动化,2017,41(11):142-149.Zhou Ye,Wang Keyou,Li Guojie.Distributed hierarchical control for micro-grid based on multi-agent consensus algorithm[J].Automation of Electric Power Systems,2017,41(11):142-149(in Chinese).
[14]胡健,马皓.基于多智能体系统的微网功率经济分配方法[J].电网技术,2017,41(8):2657-2666.Hu Jian,Ma Hao.Multi-agent system based optimal power dispatch algorithm for micro-grid[J].2017,41(8):2657-2666(in Chinese).
[15]Xin H,Zhao R,Zhang L,et al.A decentralized hierarchical control structure and self-optimizing control strategy for F-P type DGs in islanded micro-grids[J].IEEETransactions on Smart Grid,2016,7(1):3-5.
[16]Li Z,Zang C,Zeng P,et al.Fully distributed hierarchical control of parallel grid-supporting inverters in islanded AC microgrids[J].IEEE Transactions on Industrial Informatics,2018,14(2):679-690.
[17]程军照,李澎森,吴在军,等.微电网下垂控制中虚拟电抗的功率解耦机理研究[J].电力系统自动化,2013,36(7):27-32.Cheng Junzhao,Li Pengsen,Wu Zaijun,et al.Analysis of power decoupling mechanism for droop control with virtual inductance in a micro-grid[J].Automation of Electric Power Systems,2013,36(7):27-32(in Chinese).
[18]Liu K,Lewis F L.Robust control techniques for general dynamic systems[J].Journal of Intelligent and Robotic Systems,1992,6(1):33-49.
[19]TornambéA.High-gain observers for non-linear systems[J].International Journal of Systems Science,1992,23(9):1475-1489.
[20]Xin H,Liu Y,Qu Z,et al.Distributed control and generation estimation method for integrating high-density photovoltaic systems[J].IEEE Transactions on Energy Conversion,2014,29(4):988-996.
[21]洪奕光,翟超.多智能体系统动态协调与分布式控制设计[J].控制理论与应用,2011,28(10):1506-1512.Hong Yiguang,Zhai Chao.Dynamic coordination and distributed control design of multi-agent systems[J].Control Theory&Applications,2011,28(10):1506-1512(in Chinese).
[22]王逸超,罗安,金国彬.微网逆变器的改进鲁棒下垂多环控制[J].电工技术学报,2015,30(22):116-123.Wang Yichao,Luo An,Jin Guobin.Improved robust droop multiple loop control for parallel inverters in micro-grid[J].Transactions of China Electro technical Society,2015,30(22):116-123(in Chinese).
[23]Slotine,Jean-Jacques E,Li Weiping.Applied nonlinear control[M].Englewood Cliffs,NJ:Prentice Hall,1991:110-150.
[24]Fischer N,Kan Z,Kamalapurkar R,et al.Saturated RISEfeedback control for a class of second-order nonlinear systems[J].IEEE Transactions on Automation Control,2014,59(4):1094-1099.
[25]Kamalapurkar R,Fischer N,Obuz S,et al.Time-varying input and state delay compensation for uncertain nonlinear systems[J].IEEE Transactions on Automatic Control,2016,61(3):834-839.
[2]杨新法,苏剑,吕志鹏,等.微电网技术综述[J].中国电机工程学报,2014,34(1):57-70.Yang Xinfa,Su Jian,LüZhipeng,et al.Overview on micro-grid technology[J].Proceedings of the CSEE,2014,34(1):57-70(in Chinese).
[3]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(in Chinese).
[4]孙孝峰,郝彦丛,赵巍,等.孤岛微电网无通信功率均分和电压恢复研究[J].电工技术学报,2016,31(1):55-61.Sun Xiaofeng,Hao Yancong,Zhao Wei,et al.Research of power sharing and voltage restoration without communication for island micro-grid[J].Transactions of China Electrotechnical Society,2016,31(1):55-61(in Chinese).
[5]梁海峰,郑灿,高亚静,等.微网改进下垂控制策略研究[J].中国电机工程学报,2017,37(17):4901-4910.Liang Haifeng,Zhang Can,Gao Yajing,et al.Research on improved droop control strategy for micro-grid[J].Proceedings of the CSEE,2017,37(17):4901-4910(in Chinese).
[6]刘尧,林超,陈滔,等.基于自适应虚拟阻抗的交流微电网无功功率-电压控制策略[J].电力系统自动化,2017,41(5):16-21.Liu Yao,Lin Chao,Chen Tao,et al.Reactive power-voltage control strategy of AC micro-grid based on adaptive virtual impedance[J].Automation of Electric Power Systems,2017,41(5):16-21(in Chinese).
[7]程军照,王文玺,陈江波.采用虚拟电抗的孤立微网负荷按比例分担控制方法[J].高电压技术,2016,42(7):2142-2148.Cheng Junzhao,Wang Wenxi,Chen Jiangbo.Control strategy of sharing power in proportion for autonomous micro-grid by virtual inductance[J].High Voltage Engineering,2016,42(7):2142-2148(in Chinese).
[8]苏晨,吴在军,吕振宇,等.孤立微电网分布式二级功率优化控制[J].电网技术,2016,40(9):2690-2697.Su Chen,Wu Zaijun,LüZhenyu,et al.Distributed secondary power optimization control for islanded microgrid[J].Power System Technology,2016,40(9):2690-2697(in Chinese).
[9]余志文,艾芊,熊文.基于多智能体一致性协议的微电网分层分布实时优化策略[J].电力系统自动化,2017,41(18):25-33.Yu Zhiwen,Ai Qian,Xiong Wen.Hierarchical distributed real-time optimization strategy for micro-grid based on consistency protocol of multi-agent system[J].Automation of Electric Power Systems,2017,41(18):25-33(in Chinese).
[10]Guerrero J,Chandorkar M,Lee T,et al.Advanced control architectures for intelligent microgrids-Part I:Decentralized and hierarchical control[J].IEEETransactions on Industrial Electronics,2013,60(4):1254-1262.
[11]赵睿,章雷其,辛焕海,等.微网孤岛运行的分散自趋优控制策略[J].电力系统自动化,2015,39(21):30-36.Zhao Rui,Zhang Leiqi,Xin Huanhai,et al.Adecentralized self-optimizing control strategy for islanded microgrid[J].Automation of Electric Power Systems,2015,39(21):30-36(in Chinese).
[12]陈萌,肖湘宁.基于分布式内模设计的微电网协调二次控制策略[J].电工技术学报,2017,32(10):145-154.Chen Meng,Xiao Xiangning.Cooperative secondary control strategy of micro-grids based on distributed internal model design[J].Transactions of China Electro technical Society,2017,32(10):145-154(in Chinese).
[13]周烨,汪可友,李国杰.基于多智能体一致性算法的微电网分布式分层控制策略[J].电力系统自动化,2017,41(11):142-149.Zhou Ye,Wang Keyou,Li Guojie.Distributed hierarchical control for micro-grid based on multi-agent consensus algorithm[J].Automation of Electric Power Systems,2017,41(11):142-149(in Chinese).
[14]胡健,马皓.基于多智能体系统的微网功率经济分配方法[J].电网技术,2017,41(8):2657-2666.Hu Jian,Ma Hao.Multi-agent system based optimal power dispatch algorithm for micro-grid[J].2017,41(8):2657-2666(in Chinese).
[15]Xin H,Zhao R,Zhang L,et al.A decentralized hierarchical control structure and self-optimizing control strategy for F-P type DGs in islanded micro-grids[J].IEEETransactions on Smart Grid,2016,7(1):3-5.
[16]Li Z,Zang C,Zeng P,et al.Fully distributed hierarchical control of parallel grid-supporting inverters in islanded AC microgrids[J].IEEE Transactions on Industrial Informatics,2018,14(2):679-690.
[17]程军照,李澎森,吴在军,等.微电网下垂控制中虚拟电抗的功率解耦机理研究[J].电力系统自动化,2013,36(7):27-32.Cheng Junzhao,Li Pengsen,Wu Zaijun,et al.Analysis of power decoupling mechanism for droop control with virtual inductance in a micro-grid[J].Automation of Electric Power Systems,2013,36(7):27-32(in Chinese).
[18]Liu K,Lewis F L.Robust control techniques for general dynamic systems[J].Journal of Intelligent and Robotic Systems,1992,6(1):33-49.
[19]TornambéA.High-gain observers for non-linear systems[J].International Journal of Systems Science,1992,23(9):1475-1489.
[20]Xin H,Liu Y,Qu Z,et al.Distributed control and generation estimation method for integrating high-density photovoltaic systems[J].IEEE Transactions on Energy Conversion,2014,29(4):988-996.
[21]洪奕光,翟超.多智能体系统动态协调与分布式控制设计[J].控制理论与应用,2011,28(10):1506-1512.Hong Yiguang,Zhai Chao.Dynamic coordination and distributed control design of multi-agent systems[J].Control Theory&Applications,2011,28(10):1506-1512(in Chinese).
[22]王逸超,罗安,金国彬.微网逆变器的改进鲁棒下垂多环控制[J].电工技术学报,2015,30(22):116-123.Wang Yichao,Luo An,Jin Guobin.Improved robust droop multiple loop control for parallel inverters in micro-grid[J].Transactions of China Electro technical Society,2015,30(22):116-123(in Chinese).
[23]Slotine,Jean-Jacques E,Li Weiping.Applied nonlinear control[M].Englewood Cliffs,NJ:Prentice Hall,1991:110-150.
[24]Fischer N,Kan Z,Kamalapurkar R,et al.Saturated RISEfeedback control for a class of second-order nonlinear systems[J].IEEE Transactions on Automation Control,2014,59(4):1094-1099.
[25]Kamalapurkar R,Fischer N,Obuz S,et al.Time-varying input and state delay compensation for uncertain nonlinear systems[J].IEEE Transactions on Automatic Control,2016,61(3):834-839.