Stability analysis and dynamic performance enhancement of autonomous microgrid using adaptive fuzzy PI controller

In this paper, an adaptive fuzzy proportional-integral (AFPI) controller is proposed to improve the dynamic performance of the inverter interfaced autonomous microgrid. For this purpose, an accurate small signal state space model of the microgrid with electronically interfaced distributed generation (DG) units is developed. The developed model includes the network dynamics, controller dynamics, dynamics of LCL filter and load dynamics. In addition, the effect of damping resistor is also included in the proposed model to show its effect on damping high frequency oscillatory modes. After that, eigenvalue analysis is carried out to determine the optimal ranges of critical control parameters, which greatly affects the small signal stability of the microgrid. Finally based on the analysis, an AFPI controller is designed here to enhance the dynamic performance of the autonomous microgrid during disturbances. To validate the effectiveness of the proposed controller, nonlinear time domain simulation is carried out using Matlab/Simulink and results are compared with conventional proportional integral (PI) controller and also with other existing intelligent controllers to show the superiority of the proposed controller.