改进的空间状态模型和含逆变器的微网孤岛运行分析

Improved State-space Model and Analysis of Islanding Inverter-based Microgrid

对含逆变器的微型电网传统状态空间模型做了改进,使其更准确地描述微网。逆变器不可以简化为一个独立的部分,其通过公共旋转坐标系,把耦合项和公共旋转坐标系的角度都考虑在内。基于对微网改进后状态空间系统模型的特征根进行稳定性分析,可以表明振荡元件在暂态过程中的频率和阻尼。参与矩阵的引入,其可以用于识别特征值和状态变量之间的关系,并找出影响最大的状态变量的参与因子大的特征值,这将有助于提高微电网系统的稳定并降低系统阶数。仿真和实验对象是以3个容量为100 kW逆变器为基础的微电网,用以证实模型改进的效果。

Based on the traditional modeling method of the inverter-based microgrid, this paper makes some improvement on the state-space model to describe the microgrid more precisely. The coupling item, variation of common rotating angle, in the state-matrix of inverters model introduced by the common rotating reference frame are considered, which isn＇t simplified as the inverters individual part as before. Stability analysis based on the eigenvalues of the microgrid improved statespace system model is made, which indicate the frequency and damping of oscillatory components in the transient response. The participation matrix is introduced to identify the relation between the eigenvalues and the state-variables and to find out the most valuable state-variables for certain eigenvalues, which will helpful to improve the microgrid system stability and reduce the order of the system. Simulation and experiment results are carried out based on a three 100 kW inverter based microgrid to verify the corresponding results obtained from the improved model.