直流微电网稳定性分析及阻尼控制方法研究  

Stability Analysis and Research of Active Damping Method for DC Microgrids

作　　者：郭力[1] 冯怿彬 李霞林[1] 王成山[1] 李运帷[2] 

机构地区：[1]智能电网教育部重点实验室(天津大学),天津市南开区300072 [2]阿尔伯塔大学电气与计算机工程系

出　　处：《中国电机工程学报》2016年第4期927-936,共10页Proceedings of the CSEE

基　　金：国家863高技术基金项目(2015AA050104);国家自然科学基金项目(51507109);天津市科技支撑计划重点资助项目(14ZCZDGX00035)~~

摘　　要：该文以下垂控制直流微电网为研究对象,首先推导直流系统的小信号模型,通过特征值分析,研究负荷功率及类型、变流器下垂系数等参数变化对系统稳定性的影响,发现当变流器采用详细建模时,系统中由线路的等效电抗与变流器的稳压电容构成的低阻尼LC环节会与电压源型变流器的输出阻抗相互影响,导致直流微电网发生高频振荡失稳现象,给稳定运行带来不利影响。文中利用阻抗匹配准则,提出基于低通滤波的有源阻尼方法,通过改变变流器的等效输出阻抗,使主导特征根向s域平面左侧移动。仿真与实验结果表明,系统参数变化对稳定性的影响与理论分析一致;该有源阻尼方法能有效增大系统阻尼,改善系统的稳定性。This paper focused on a DC microgfid with droop control structure. The small-signal models had been derived in the s plane. Eigenvalue analysis results revealed the relationship between system stability and the parameters of DC system, such as DC load power, the type of DC load and the droop gains. It shows that when the converter adopts the detailed modeling, the poorly damped LC filter in DC mierogrid, which consists of the capacitor of converter and equivalent reactance of eormecting cable, will have interaction with the output impedance of converter and may reduce the system damping and bring in unstable high,frequency oscillations. Based on the impedance ratio type criterions, a low-pass-based active damping method was proposed to change the original unstable root locus and overcome the unstable oscillations by reshaping the equivalent output impedance of DC-DC converters. Simulation and experimental results were carded out to confirm the validity of the proposed approach.

关 键 词：直流微电网 下垂控制 稳定性分析 高频谐振 有源阻尼方法 

分 类 号：TM71[电气工程—电力系统及自动化]