基于改进变参考电压法的下垂控制策略研究
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摘要
微电网在孤岛模式下多逆变器并联运行,并联系统采用传统下垂控制策略时,存在由于线路阻抗差异造成无功功率分配不合理的问题,为解决此问题对现有文献中的变参考电压法加以改进。提出针对线路阻抗差值通过功率补偿系数匹配阻抗差值来调节各逆变器的参考电压。该改进控制策略不仅实现了无功功率的合理分配和无功环流的抑制,而且避免了系统出现较大的电气波动,保证逆变器输出端电压的质量。在MATLAB中搭建两台并联逆变器的仿真模型,通过对比分析改进策略与传统的下垂控制策略。仿真结果验证了该改进策略兼顾功率的合理分配和输出端的电压的稳定性的制两方面的要求,有效抑制系统无功环流。
In the micro-grid, inverters operate in parallel in island mode. When the parallel system adopts the traditional droop control strategy, there comes up the unreasonable distribution of reactive power due to line impedance difference. Given such situation, this paper proposed an improved droop control strategy by revising the existing variable reference voltage method. To be more specific, the reference voltage of each inverter is adjusted by matching the power compensation coefficient with the line impedance difference. The improved control strategy realizes the reasonable distribution of reactive power and the suppression of reactive circulating current. It also avoids wider electrical fluctuations in the system, thus ensuring the quality of inverter output voltage. This paper built a simulation model of two parallel inverters in MATLAB to compare the improved strategy and the traditional droop control strategy. The simulation results verified that the improved strategy guarantees both reasonable power distribution and stability of output voltage, effectively suppressing the reactive circulating current of the system.
In the micro-grid, inverters operate in parallel in island mode. When the parallel system adopts the traditional droop control strategy, there comes up the unreasonable distribution of reactive power due to line impedance difference. Given such situation, this paper proposed an improved droop control strategy by revising the existing variable reference voltage method. To be more specific, the reference voltage of each inverter is adjusted by matching the power compensation coefficient with the line impedance difference. The improved control strategy realizes the reasonable distribution of reactive power and the suppression of reactive circulating current. It also avoids wider electrical fluctuations in the system, thus ensuring the quality of inverter output voltage. This paper built a simulation model of two parallel inverters in MATLAB to compare the improved strategy and the traditional droop control strategy. The simulation results verified that the improved strategy guarantees both reasonable power distribution and stability of output voltage, effectively suppressing the reactive circulating current of the system.
引文
[1] 王成山,李琰,彭克.分布式电源并网逆变器典型控制方法综述[J].电力系统及其自动化学报,2012,24(2):12-20.WANG Chengshan,LI Yan,PENG Ke.Overview of typical control methods for Grid-Connected Inverts of Distributed Generation[J].Proceeding of the CSU-EPSA,2012,24(2):12-20.
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[8] 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,ZHEN Can,GAO Yajing,et al.Research on Improved Droop Control Strategy for Microgrid[J].Proceedings of the CSEE,2017,37(17):4901-4910.
[9] 姚玮,陈敏,牟善科,等.基于改进下垂法的微电网逆变器并联控制技术[J].电力系统自动化,2009,33(6):77-80.YAO Wei,CHEN Min,MOU Shanke,et al.Paralleling control technique of microgrid inverters based on improved droop method[J].Automation of Electric Power Systems,2009,33(6):77-80.
[10] 谢玲玲,时斌,华国玉,等.基于改进下垂法的微电网逆变器并联控制技术[J].电网技术,2013,37(4):992-998.XIE Lingling,SHI Bin,HUA Guoyu,et al.Parallel Operation Technology of Distrubited Generations Based on Improved Droop Contol[J].Power System Technology,2013,37(4):992-998
[11] 李红萍,杨洪耕,曾巧燕,等.孤岛型微电网中改进下垂控制策略[J].电力系统及其自动化学报,2017,29(4):49-54.LI Hongping,YANG Honggeng,ZENG Qiaoyan,et al.Improved Droop Control Strategy for Islanded Microgrid[J].Proceedings of the CSU-EPSA,2017,29(4):49-54.
[12] 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.
[13] 张洁,刘天琪,刘建华,等.提高微电网孤岛运行下垂控制动态性能的策略[J].电力系统及其自动化学报,2015,27(5):75-80.ZHANG Jie,LIU Tianqi,LIU Jianhua,et al.Droop control strategy for enhanced dynamic performance in islanding microgrid[J].Proceeding of the CSU-EPSA,2015,27(5):75-80.
[14] 姚骏,杜红彪,周特,等.微网逆变器并联运行的改进下垂控制策略[J].电网技术,2015,39(4):932-938.YAO Jun,DU Hongbiao,ZHOU Te,et al.Improved Droop Control Strategy for Inverters Parallel Operation in Micro-Gird[J].Power System Technology,2015,39(4):932-938.
[15] 徐玉琴,马焕均.基于改进下垂控制的逆变器并联运行技术[J].电力系统保护与控制,2015,43(7):103-107.XU Yuqin,MA Huanjun.Parallel operation technology of invers based droop control[J].Power System Protection and Control,2015,43(7):103-107.
[16] 徐瑞林,徐鑫,郑永伟,等.基于改进下垂控制的微网运行控制策略[J].电力系统及其自动化学报,2009,33(6):77-80.XU Ruilin,XU Xin,ZHENG Yongwei,et al.Improved Droop Control scheme for Micro-grid Operation[J].Proceedings of the CSU-EPSA,2009,33(6):77-80.
[17] 陈堃,陈昌旺,刘涤尘.逆变器并联系统直流环流瞬时抑制策略[J].高电压技术,2014,40(2):604-610.CHEN Kun,CHEN Changwang,LIU Dichen.Strategy for instantaneously restraining DC circulating current in parallel inverter system[J].High Voltage Engineering,2014,40(2):604-610.
[18] 胡应宏,邓春,王劲松,等变流器并列运行系统中非特征谐波环流分析及其抑制方法[J].电网技术,2016,40(7):2169-2174.HU Yinghong,DENG Chun,WANG Jinsong,et al.Analysis on non-characteristic harmonic circulating current in parallel inverter system and its suppression measure[J].Power System Technology,2016,40(7):2169-2174.
[2] ZAMANI M A,SIDHU T S,YAZDANI A.Investigations into thecontrol and protection of an existing distribution network to operate as a microgrid:a case study[J].IEEE Transactions on Industrial Electronics,2014,61 (4):1904-1915.
[3] 张东,卓放,师洪涛,等.基于下垂系数步长自适应的下垂控制策略[J].电力系统自动化,2014,38(24):20-25.ZHANG Dong,ZHUO Fang,SHI Hongtao,et al.A droop control Strategy based on drooping coefficient with adaptively changing step[J].Automation of Electic Power System,2014,38(24):20-25.
[4] 徐诚,刘念,赵泓,等.基于电力系统二次调频原理的微电源频率控制策略[J].电力系统保护与控制,2013,41(3):14-20.XU Cheng,LIU Lian,ZHAO Hong,et al.A novel frequency control strategy of micro-grid based on the secondary frequency regulation of power system[J].Power System Protection and Control,2013,41(3):14-20.
[5] 苏虎,曹炜,孙静,等.基于改进下垂控制的微网协调控制策略 [J].电力系统保护与控制,2014,42(11):92-98.SU Hu,CAO Wei,SUN Jing,et al.Micro-grid coordinated control strategy based on improved droop control[J].Power System Protection and Control,2014,42(11):92-98.
[6] 肖华根,罗安,王逸超,等.微网并联逆变器的环流控制方法[J].电机工程学报,2014,34(19):3098-3104.XIAO Huagen,LUO An,WANG Yichao,et al.A circulating current control method for Paralleled inverters in microgrids[J].Proceedings of the CSEE,2014,34(19):3098-3104.
[7] 朱永兴.虚拟复阻抗在微网下垂控制中的应用[J].电力系统及其自动化学报,2014,26(3):66-71.ZHU Yongxing.Application of virtual negative resistance on microgrid droop control[J].Proceeding of the CSU-EPSA,2014,26(3):66-71.
[8] 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,ZHEN Can,GAO Yajing,et al.Research on Improved Droop Control Strategy for Microgrid[J].Proceedings of the CSEE,2017,37(17):4901-4910.
[9] 姚玮,陈敏,牟善科,等.基于改进下垂法的微电网逆变器并联控制技术[J].电力系统自动化,2009,33(6):77-80.YAO Wei,CHEN Min,MOU Shanke,et al.Paralleling control technique of microgrid inverters based on improved droop method[J].Automation of Electric Power Systems,2009,33(6):77-80.
[10] 谢玲玲,时斌,华国玉,等.基于改进下垂法的微电网逆变器并联控制技术[J].电网技术,2013,37(4):992-998.XIE Lingling,SHI Bin,HUA Guoyu,et al.Parallel Operation Technology of Distrubited Generations Based on Improved Droop Contol[J].Power System Technology,2013,37(4):992-998
[11] 李红萍,杨洪耕,曾巧燕,等.孤岛型微电网中改进下垂控制策略[J].电力系统及其自动化学报,2017,29(4):49-54.LI Hongping,YANG Honggeng,ZENG Qiaoyan,et al.Improved Droop Control Strategy for Islanded Microgrid[J].Proceedings of the CSU-EPSA,2017,29(4):49-54.
[12] 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.
[13] 张洁,刘天琪,刘建华,等.提高微电网孤岛运行下垂控制动态性能的策略[J].电力系统及其自动化学报,2015,27(5):75-80.ZHANG Jie,LIU Tianqi,LIU Jianhua,et al.Droop control strategy for enhanced dynamic performance in islanding microgrid[J].Proceeding of the CSU-EPSA,2015,27(5):75-80.
[14] 姚骏,杜红彪,周特,等.微网逆变器并联运行的改进下垂控制策略[J].电网技术,2015,39(4):932-938.YAO Jun,DU Hongbiao,ZHOU Te,et al.Improved Droop Control Strategy for Inverters Parallel Operation in Micro-Gird[J].Power System Technology,2015,39(4):932-938.
[15] 徐玉琴,马焕均.基于改进下垂控制的逆变器并联运行技术[J].电力系统保护与控制,2015,43(7):103-107.XU Yuqin,MA Huanjun.Parallel operation technology of invers based droop control[J].Power System Protection and Control,2015,43(7):103-107.
[16] 徐瑞林,徐鑫,郑永伟,等.基于改进下垂控制的微网运行控制策略[J].电力系统及其自动化学报,2009,33(6):77-80.XU Ruilin,XU Xin,ZHENG Yongwei,et al.Improved Droop Control scheme for Micro-grid Operation[J].Proceedings of the CSU-EPSA,2009,33(6):77-80.
[17] 陈堃,陈昌旺,刘涤尘.逆变器并联系统直流环流瞬时抑制策略[J].高电压技术,2014,40(2):604-610.CHEN Kun,CHEN Changwang,LIU Dichen.Strategy for instantaneously restraining DC circulating current in parallel inverter system[J].High Voltage Engineering,2014,40(2):604-610.
[18] 胡应宏,邓春,王劲松,等变流器并列运行系统中非特征谐波环流分析及其抑制方法[J].电网技术,2016,40(7):2169-2174.HU Yinghong,DENG Chun,WANG Jinsong,et al.Analysis on non-characteristic harmonic circulating current in parallel inverter system and its suppression measure[J].Power System Technology,2016,40(7):2169-2174.