摘要
孤岛运行微电网存在因线路阻抗不一致引起的分布式电源(DG)输出功率无法按其容量比例分配问题。针对上述问题,利用电压-电流(U-I)下垂特性对各DG输出电压幅值进行控制,通过卫星授时技术产生相位相同、频率固定的输出电压。进一步利用同步定频微电网中的同步信息,对不同测点电压电流同步测量,实现对线路阻抗的主动辨识。在此基础上,提出基于虚拟负阻抗的改进下垂控制策略,可实现线路阻抗的完全补偿,各DG按其容量比例精确分配功率。此外,为提高系统稳定性,通过奈奎斯特曲线分析虚拟负阻抗的参数对系统稳定性的影响,为参数设计提供依据。最后通过仿真和实验结果验证了所提方法可使DG输出有功功率及无功功率按其容量比例精确分配。
When the microgrid works in islanded mode,the output power of distributed generation(DG)cannot be shared in proportion to its capacity because of the inconsistent line impedance.To address the above problem,an improved droop control for power sharing strategy is proposed.Specifically,the output voltage of each DG is controlled using the voltage-current(U-1)droop characteristic,where the satellite timing is used for synchronous control.Further,synchronization information is used to synchronize voltage and current measurements at different measurement points to achieve active identification of line impedance.On this basis,virtual negative impedance is used to achieve complete compensation of the line impedance,so that each DG can precisely share power in proportion to its capacity.In addition,the influence of the parameters of virtual negative impedance on the system stability is analyzed by the Nyquist curve to provide a basis for the parameter design.Finally,simulation and experimental results verify that the proposed method can accurately allocate the active and reactive power output of DG according to its capacity ratio.
作者
周国良
赵艳雷
李海龙
李扬
ZHOU Guo-liang;ZHAO Yan-lei;LI Hai-long;LI Yang(Shandong University of Technology,Zibo 255000,China)
出处
《电力电子技术》
北大核心
2023年第5期80-84,共5页
Power Electronics
基金
国家重点研发计划(2017YFB0902804)。
关键词
微电网
虚拟负阻抗
下垂控制
microgrid
virtual negative impedance
droop control
