State-Space Modeling and Stability Analysis for Microgrids with Distributed Secondary Control

High penetration of renewable energies in power systems leads to the necessity of comprehensive modelling of a microgrid (MG) for its appropriate control. The distributed secondary control in the MG can be used for complementing the role of primary droop-based control. This paper presents a systematic way of developing a linearized small signal state space model with distributed secondary control as well as stability analysis of an islanded AC MG. The MG considered here, consists of three distributed generations (DGs) represented in the synchronous (DQ) reference frame. To show the effect of controller parameters on system stability, the eigenvalue analysis is presented here. The MATLAB/Simulink model of islanded MG with both primary and secondary control strategies is also developed to verify the outcomes of small-signal analysis. The simulation results show that the voltage controller simultaneously achieves the critical voltage restoration and accurate reactive power sharing.