基于线路阻抗辨识的微电网无功均分改进下垂控制策略

发布时间：2018-05-31 00:28

本文选题：微电网 + 线路阻抗辨识　；参考：《高电压技术》2017年04期

【摘要】：在孤岛运行的微电网中,分布式电源(DG)以并联方式运行,在其等效线路阻抗不匹配的情况下,传统的下垂控制难以按无功功率-电压的下垂方式对无功功率进行合理分配。为此,提出了一种基于线路辨识的改进下垂控制来消除无功功率分配的偏差。首先,详细分析了线路参数对传统下垂控制效果的影响;其次,针对单个分布式电源,构建了基于本地信号的线路观测环节,以对分布式电源的连接等效线路阻抗进行精确辨识,并在传统下垂控制中基于线路辨识结果加入了电压补偿项,使它在等效线路阻抗不匹配时,仍能保持无功功率的合理分配;最后,将提出的改进下垂控制策略应用于一个典型的微电网系统,并利用MATLAB/Simulink仿真验证了所提方法在多工况下的正确性和有效性。仿真结果表明:所提出的主动线路观测器可基于本地信号较精确地辨识出等效线路阻抗的实际值,基于该线路辨识结果,可有效对DG等效连接线路的不匹配电压降进行补偿,从而实现无功功率的合理分配;该改进方案无需依靠实时通信系统交换各DG源间的信息,也不需要利用中央控制器发送同步信号来保持改进控制启动的同步性。研究结果证明了所提改进下垂控制策略的有效性。
[Abstract]:In the isolated microgrid, the distributed power generation (DG) is operated in parallel. When the equivalent line impedance is not matched, the traditional droop control is difficult to distribute the reactive power reasonably according to the droop mode of reactive power and voltage. Therefore, an improved droop control based on line identification is proposed to eliminate the bias of reactive power allocation. Firstly, the influence of line parameters on traditional droop control is analyzed in detail. Secondly, the line observation link based on local signal is constructed for a single distributed power source. In order to accurately identify the equivalent line impedance of the distributed power supply, a voltage compensation term is added to the traditional sag control based on the line identification results, so that it can still maintain the rational allocation of reactive power when the equivalent line impedance mismatches. Finally, the proposed improved droop control strategy is applied to a typical microgrid system, and the correctness and effectiveness of the proposed method are verified by MATLAB/Simulink simulation. The simulation results show that the proposed active line observer can accurately identify the actual value of the equivalent line impedance based on the local signal. Based on the line identification results, the proposed active line observer can effectively compensate the mismatch voltage drop of the DG equivalent connection line. The improved scheme does not need to rely on real-time communication system to exchange information between DG sources, nor does it need to use the central controller to send synchronous signals to keep the synchronization of the improved control start. The results show that the proposed improved droop control strategy is effective.
【作者单位】：天津大学智能电网教育部重点实验室;中华人民共和国科学技术部高技术研究发展中心;
【基金】：国家高技术研究发展计划(863计划)(2015AA050403) 国家自然科学基金(51377117;51307115)~~
【分类号】：TM727

【相似文献】