Distributed security secondary control for cyber-physical microgrids systems under network DoS attacks

This paper considers the frequency regulation and power-sharing problems for cyber-physical microgrids (MGs) under network denial-of-service (DoS) attacks and time-varying communication delays. Compared to conventional distributed controllers based on a system model with ideal communication, a distributed security control protocol is designed. Benefiting from the developed security control method, the adverse effects of network DoS attacks and communication delays can be resisted. Then, a sufficient condition, which is used to achieve the achieve frequency restoration and power-sharing, is established according to the frequency and duration of DoS attacks. By using the average dwell time method and the Lyapunov stability theory, it is theoretically proved that the proposed control scheme can guarantee the stability of the overall AC microgrid system. In order to illustrate the proposed scheme, simulation studies are carried out based on an islanded AC microgrid system with four distributed generators (DGs) built in the simulation. The results do show its effectiveness and also verify the established theoretical results.