An Estimator-Based Distributed Voltage-Predictive Control Strategy for AC Islanded Microgrids

This paper presents an estimator-based voltage-predictive control strategy for ac islanded microgrids, which is able to perform voltage control without any communication facilities. The proposed control strategy is composed of a network voltage estimator and a voltage-predictive controller for each distributed generator, where the voltage estimator serves as an essential tool to obtain network voltages response without using communication links, while the voltage-predictive controller is able to implement offset-free voltage control for a specified bus. The dynamic performance of the proposed voltage control strategy is analyzed through small-signal analysis method, from which the design guideline for the controller parameters is formulated. Furthermore, the robustness of the proposed voltage control strategy is investigated under a series of parameters uncertainties, including the line parameters perturbation, load parameters variation, different disturbance locations, LC filters perturbation, output impedances perturbation, and DG unit fault. The simulation and experimental results show that the proposed control approach is able to perform offset-free voltage control without any communication links and has a good capability to reject uncertain perturbations of islanded microgrids.