Distributed Discrete-Time Secondary Cooperative Control for AC Microgrids With Communication Delays
Tao Yang, Shikuan Sun, Shuai Liu
Abstract
This article presents a droop-based distri-buted discrete-time secondary cooperative control scheme for ac microgrids with communication delays, which can regulate the voltage and frequency of all distributed generators (DGs) and ensure that each DG obtains active power sharing accurately. Unlike the ideal communication among DGs, the delays caused by low-band-bandwidth communication networks generally lead to potential oscillation and endanger the system stable operation. To this end, the proposed control protocol aims to compensate the general communication delays for cyber-physical microgrids actively by using the predictive control theory while realizing voltage and frequency recovery as well as active power sharing precisely. Moreover, each DG only needs to share information with its neighbors in the proposed scheme, and sufficient conditions for achieving stability of the closed-loop control systems are derived. The effectiveness of the control strategy is also verified by simulation studies and some experiments on the OPAL-RT platform.