Distributed Cooperative Secondary Control for Islanded Microgrid With Markov Time-Varying Delays

Abstract

The network-induced delays have a great impact on microgrid performance and stability. In this paper, we proposed a distributed cooperative secondary control with stochastic Markov time-varying network-induced delays, by which both output voltage/frequency restoration and active power sharing can be obtained. A new small-signal model of the microgrid control system is developed, and a small-signal model-based information Kalman observer is introduced to acquire the estimated state vector. Then, the global closed-loop stochastic system accommodated by the Markov time-varying network-induced delays of the microgrid is derived, and the corresponding global stability theorem is introduced. Finally, the simulation of a microgrid test system is presented to verify the control performance. The results show that our approach has accurate regulations on voltage/frequency restoration and active power sharing in terms of load variations, plug-and-play capability, and network-induced delays. In addition, the control gain parameters and network-induced delays effects on the microgrid secondary control are also verified.