Distributed Secondary Control of Energy Storage Systems in Islanded AC Microgrids

In this paper, a distributed secondary control scheme of energy storage systems (ESSs) in islanded alternative current (AC) microgrids has been proposed. In order to investigate the secondary control of AC microgrids, a microgrid prototype and its associated hierarchical control have been built. As the foundation, the primary control including voltage and current control loops, droop control and virtual impedance has been developed first. Then, the microgrid secondary control functionalities including frequency restoration, voltage restoration as well as state-of-charge balancing of ESSs have been achieved in a distributed way. A novel distributed secondary control scheme for islanded AC microgrid has been proposed. Compared with centralized approach, only peer-to-peer communication is required by proposed the secondary control. The proposed control scheme is robust against communication failures, so that the cyber resilience of the microgrid control is enhanced. The proposed method is evaluated in the established Matlab/Simulink model and the results validate the effectiveness of the proposed method.