使用自适应虚拟阻抗的孤岛微网无功均分控制
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摘要
当微电网运行在孤岛模式时,每个发电单元都需要实现较好的负载均分。针对这个问题,提出了一种结合通讯和虚拟阻抗的无功功率精确均分控制策略。该策略利用建立的通讯来促进自适应虚拟阻抗的调整,以补偿不同馈线导致的电压下降。在给定的负载工作点,如果虚拟阻抗调整完毕,即使通讯中断也可以实现精准的无功功率均分。通讯中断后,如果负载点变化,无功功率均分度有所下降,但仍好于传统的下垂控制。此外,新型控制策略的无功功率均分度不受到通信延迟的影响,同时也不需要馈线阻抗的信息,易于实施。最后,通过2 k V·A微网试验平台对控制策略的有效性进行了试验验证。
When the microgrid is operating in the island mode,each distributed generation unit needs to achieve a good load sharing. Aiming at this problem,a method using communication and adaptive virtual impedances to control reactive power accurate sharing was proposed. The strategy used the established communication to facilitate the adjustment of the adaptive virtual impedance to compensate for the voltage drop caused by different feeders of the distributed generation units. At a given load operating point,if the virtual impedance adjustment was completed,even if the communication was interrupted,the precision of the reactive power still could be achieved. After the communication was interrupted,if the load point was changed,the reactive power was declined,but it was still better than the traditional droop controller. In addition,the new control strategy of reactive power was not affected by the impact of the communication delay,and also did not require the information of the feeder impedance. So,it was easy to implement.Finally,some tests had been done in a 2 k V·A microgrid network experiment platform. And the experimental results prove the effectiveness of the new control strategy.
When the microgrid is operating in the island mode,each distributed generation unit needs to achieve a good load sharing. Aiming at this problem,a method using communication and adaptive virtual impedances to control reactive power accurate sharing was proposed. The strategy used the established communication to facilitate the adjustment of the adaptive virtual impedance to compensate for the voltage drop caused by different feeders of the distributed generation units. At a given load operating point,if the virtual impedance adjustment was completed,even if the communication was interrupted,the precision of the reactive power still could be achieved. After the communication was interrupted,if the load point was changed,the reactive power was declined,but it was still better than the traditional droop controller. In addition,the new control strategy of reactive power was not affected by the impact of the communication delay,and also did not require the information of the feeder impedance. So,it was easy to implement.Finally,some tests had been done in a 2 k V·A microgrid network experiment platform. And the experimental results prove the effectiveness of the new control strategy.
引文
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[19]彭自强,罗安,陈燕东,等.基于分频虚拟电阻的多逆变器并联控制策略[J].电网技术,2013,37(11):3276-3280.
[20]张平,石健将,李荣贵,等.低压微网逆变器的虚拟负阻抗控制策略[J].中国电机工程学报,2014,34(12):1844-1851.
[2]郝新星,苏建徽,施永,等.基于虚拟同步机的微网并离网切换策略研究[J].电气传动,2016,46(1):50-54.
[3]秦铭阳,刘闯,姜明磊.微网中并行电压电流多环反馈的单相控制策略[J].电气传动,2016,46(2):49-54.
[4]王文静,王斯成.我国分布式光伏发电的现状与展望[J].中国科学院院刊,2016,31(2):165-172.
[5]赵敏,沈沉,刘锋,等.基于博弈论的多微电网系统交易模式研究[J].中国电机工程学报,2015,35(4):848-857.
[6]郭宁,滕欢,李基康.考虑综合评估的孤立微网优化调度[J].电力建设,2016,37(4):63-69.
[7]王成山,武震,李鹏.微电网关键技术研究[J].电工技术学报,2014,29(2):1-12.
[8]马艺玮,杨苹,王月武,等.微电网典型特征及关键技术[J].电力系统自动化,2015,39(8):168-175.
[9]朱永兴.虚拟负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.
[10]鲍薇,胡学浩,李光辉,等.独立型微电网中基于虚拟阻抗的改进下垂控制[J].电力系统保护与控制,2013,41(16):7-13.
[11]Yao W,Chen M,Matas J,et al.Design and Analysis of the Droop Control Method for Parallel Inverters Considering the Impact of the Complex Impedance on the Power Sharing[J].IEEE Transactions on Industry Electronics,2011,58(2):576-588.
[12]Tuladhar A,Jin H,Unger T,et al.Control of Parallel Inverters in Distributed AC Power Systems with Consideration of Line Impedance Effect[J].IEEE Transactions on Industry Applications,2000,36(1):131-138.
[13]Li W Y,Kao N C.An Accurate Power Control Strategy for Power Electronics Interfaced Distributed Generation Units Operating in Alow Voltage Multibus Microgrid[J].IEEE Transactions on Power Electronics,2009,24(12):2977-2988.
[14]Zhong C Q.Robust Droop Controller for Accurate Proportional Load Sharing Among Inverters Operated in Parallel[J].IEEE Transactions on Industry Electronics,2013,60(4):1281-1290.
[15]Yu X,Khambadkone M A,Wang H,et al.Control of Parallelconnected Power Converters for Low-voltage Microgrid—Part I:A Hybrid Control Architecture[J].IEEE Transactions on Power Electronics,2010,25(12):2962-2970.
[16]He J,Li W Y.An Enhanced Microgrid Load Demand Sharing Strategy[J].IEEE Transactions on Power Electronics,2012,27(9):3984-3995.
[17]He J,Li W Y,Guerrero M J,et al.An Islanded Microgrid Reactive Power Sharing Scheme Enhanced by Programmed Virtual Impedances[C]//IEEE 3rd International Symposium on Power Electronics for Distributed Generation Systems,Aalborg,Denmark,2012:229-235.
[18]Shafiee Q,Guerrero M J,Vasquez C J.Distributed Secondary Control for Islanded Microgrids—A Novel Approach[J].IEEE Transactions on Power Electronics,2014,29(2):1018-1031.
[19]彭自强,罗安,陈燕东,等.基于分频虚拟电阻的多逆变器并联控制策略[J].电网技术,2013,37(11):3276-3280.
[20]张平,石健将,李荣贵,等.低压微网逆变器的虚拟负阻抗控制策略[J].中国电机工程学报,2014,34(12):1844-1851.