Distributed secondary control for discrete-time multirate microgrids with multiple description encoding strategies.

Microgrids (MGs) provide crucial solutions for integrating renewable energy resources. In such networked control scenarios, codec strategies are essential for reliable data transmission. In light of the multi-rate characteristic of control updating and sensor sampling, this paper focuses on distributed secondary control for discrete-time MGs by using a multiple description encoding scheme (MDES). First, a linear single-rate model of distributed generators is established via feedback linearization and lifting techniques. Then, a distributed secondary voltage controller is constructed under MDESs by using decoded neighbor information with zero-order compensation. Under the framework of Lyapunov stability, a sufficient condition dependent on channel parameters is derived, guaranteeing the voltage restoration performance in the mean-square sense. Furthermore, an engineering-friendly design scheme of the desired control gain matrix is proposed by the graph feature and singular value decomposition. Finally, the feasibility of the proposed control scheme is validated through several simulation examples under a modified IEEE 37-bus islanded MG system.