H∞ robustness for distributed control in autonomous microgrids considering cyber disturbances

The physical connections and logical relationships between microgrids and communication networks make microgrids develop into typical cyber-physical systems (CPSs). With the extensive use of open communication mechanisms, the impact of cyber disturbances in public communication networks cannot be negligible. In this paper, a parameter optimal method for distributed secondary controller based on the robust control theory and consensus algorithm is presented to enhance the robustness of secondary control system under data disturbance, parameter perturbation, and time delay. Firstly, a distributed secondary control strategy of microgrids is demonstrated that coordinates frequency and voltage restoration and power sharing. Then, considering the impact of cyber events on the secondary control, a distributed robust controller gain design method is proposed to satisfy the H ∞ performance index. The solution of the distributed robust control is transformed into the linear matrix inequation problem and latency margin is obtained simultaneously. Finally, a test microgrid CPS is simulated with and without time delay to investigate the impact of cyber events on system operational states and the effectiveness and robustness of the proposed method.