Nowadays the control and stability of DG system are important topics that researchers in both academia and industry have been addressing. Small and large signal analyses for stability studies on various systems have been done in papers and books. In this paper, at first models of an inverter-based Distributed Generation (DG) subsystems are created and after the linearization if be required the small-signal stability analysis of the DG which is controlled with a voltage and frequency control scheme based on model predictive control (MPC) that has been used previously is established. In this control scheme, load currents at the point of common coupling (PCC) of the DG are considered as disturbances and used as feed-forward signals. This technique enhances the performance of the DG control system in transient and steady-state conditions for a wide range of loads. The stability of the DG system under various loads (such as one phase load as imbalanced load, rectifier load as nonlinear load and induction motor load as dynamic load) is demonstrated by the eigenvalues trajectory. Also the sensitivity analysis and robustness assessment of the control scheme are conducted and discussed. For more performance consideration, the DG system is simulated with MATLAB/SIMULINK software and implemented in the lab and then suitable performance of the system is demonstrated by the simulation and experimental studies.
