An Improved Distributed Secondary Control Scheme in Islanded AC Microgrids

Following the hierarchical control architecture, this paper investigates the diffusion algorithm based distributed secondary control in islanded AC microgrids. The principle of diffusion algorithm is introduced first and then diffusion algorithm-based distributed secondary control strategies are analyzed in details. Compared to the conventional consensus algorithm employed in the secondary control, it is shown that diffusion algorithm shows a faster convergence and a smaller deviation from the nominal value. A three-node islanded AC MG is simulated and the results confirm that the proposed diffusion-based secondary control outperforms consensus-based approach in terms of voltage/frequency restoration.