Distributed controller design and stability criterion for microgrids with time-varying delay and rapid switching communication topology

Abstract

Inherent delay and packet dropout in networks produce random time-varying delay and rapid switching communication topology in microgrid systems, thereby affecting the control performance. In this paper, we propose an improved distributed cooperative secondary control strategy to overcome these disadvantages and achieve either restoration of the voltage amplitude and frequency or active power sharing. First, based on the proposed distributed controller structure, we deduce the discrete global closed-loop state-space form of the microgrid control system by modeling the random factors as a Markov process. Then, we present the theoretical stability criterion of the random system. Finally, we verify the proposed methods via several simulation experiments. The results show that the proposed control strategy achieves significantly improvement than the state-of-the-art methods and that the stability criterion can produce the correct theoretical analysis results.