Distributed Cooperative Secondary Control of Microgrids with Bounded Control Input

This paper proposes a distributed cooperative secondary control of microgrids (MG) operated in islanded mode with bounded control input. Although the primary control can maintain the voltage and frequency stable when the microgrid switches to islanded mode, it leads to the voltage and frequency of each DG deviations. The secondary control is applied to restore the voltage and frequency to their references and achieve power sharing. The MG can be considered as multi-agent systems since each DG is an agent and the communication network is modelled by a digraph. Considering the limitation of control input, a tracking strategy with bounded control input is adopted. The stability of the closed-loop system is proved in theory, and the simulation on an islanded microgrid verifies the effectiveness of the proposed control strategy.