基于下垂控制的自治微电网建模与稳定性分析

Modeling and Stability Analysis of Autonomous Microgrid Composed Based on Improved Droop Control

微电网自治运行时各分布式电源(DG)地位相等,若系统负载功率发生变化,各DG将同时参与微电网系统的频率和电压调节。各逆变器采用虚拟功率下垂控制并加入虚拟阻抗,建立了自治微电网系统的小信号模型状态方程。考虑到自治微电网系统为复杂的非线性系统,利用李雅普诺夫第一方法对其进行分析,用其来判断接口逆变器控制参数和线路参数对系统稳定运行的影响。最后使用Matlab对所选控制器参数和线路参数进行仿真验证,并在以TMS320F2812型DSP为控制板的实验平台上进行了实验验证,结果表明,在输出线路阻抗不等情况下可实现较好的功率均分并且系统运行稳定。

During autonomous operation of microgrid, every distributed generation （DG） participates in the regulation of the voltage amplitude and frequency, while the change of the load power occurs.The virtual power droop control is adopted and virtual impedance is added to inverter.The small signal model of the microgrid system in autonomous operation is established.Because autonomous microgrid system is a complex nonlinear system, this paper adopts Lya- punov＇s first method on the system stability analysis, and then bases it to estimate influence of control and line parameters of the interface inverter on the stability of the system.Finally, simulations are carried out using Matlab to demonstrate the selected control and line parameters.Experiments are carried out on the experimental platform con- trolled by TMS320F2812 DSP.The results show that the power can be realized well and the system operation is stable in the unequal output line impedance.