一种提高无功功率均分精度的下垂控制器
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摘要
低压微电网在孤岛模式运行中,受馈线阻抗影响较大,传统下垂控制的方法很难对无功功率进行合理分配,导致分布式电源间产生无功环流,影响系统稳定性。为了解决上述问题,提出了一种自适应的下垂控制器。在该策略中,下垂控制器通过增加下垂增益使无功功率达到平均分配,自动调整空载电压来消除由于下垂增益的变化而产生的电压降,维持了系统电压稳定。通过控制机理分析,在功率负载扰动的情况下,利用Matlab/Simulink分别对传统和改进的下垂控制算法进行了仿真实验分析。结果验证了改进的下垂控制策略不仅能够快速有效地稳定系统的电压和频率,还提高了无功功率均分精度。
Low-voltage microgrid is affected greatly by feeder impedance in island mode operation. The traditional droop control method is difficult to allocate the reactive power reasonably,which leads to the reactive circulation among the distributed power sources and affects the stability of the system.In order to solve the above problems,an adaptive droop controller was proposed. In this strategy,the droop controller achieved the average distribution of reactive power by increasing droop gain,and automatically adjusted the no-load voltage to eliminate the voltage drop caused by the variation of the droop gain,thus to maintain the voltage stability of the system.Through the control mechanism analysis,the traditional and improved droop control algorithms were simulated by Matlab/Simulink under the condition of power load disturbance.The results show that the improved droop control strategy can not only fastand effectively stabilize the voltage and frequency of the system,but also improve the reactive power sharing accuracy.
Low-voltage microgrid is affected greatly by feeder impedance in island mode operation. The traditional droop control method is difficult to allocate the reactive power reasonably,which leads to the reactive circulation among the distributed power sources and affects the stability of the system.In order to solve the above problems,an adaptive droop controller was proposed. In this strategy,the droop controller achieved the average distribution of reactive power by increasing droop gain,and automatically adjusted the no-load voltage to eliminate the voltage drop caused by the variation of the droop gain,thus to maintain the voltage stability of the system.Through the control mechanism analysis,the traditional and improved droop control algorithms were simulated by Matlab/Simulink under the condition of power load disturbance.The results show that the improved droop control strategy can not only fastand effectively stabilize the voltage and frequency of the system,but also improve the reactive power sharing accuracy.
引文
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[2]程军照,李澍森,吴在军,等.微电网下垂控制中虚拟电抗的功率解耦机理分析[J].电力系统自动化,2012,36(7):27-32.
[3]董晨露,杨盼盼,王洋.改进的低压微电网孤岛模式下的控制策略[J].电测与仪表,2015,52(11):69-73.
[4]王颖杰,王文超,李炎,等. LCL型并网变换器PCC点电压反馈有源阻尼控制策略[J].电气传动,2017,47(2):29-34.