Tao Yang

This paper proposes a two-layer distributed network predictive control strategy for AC microgrids (MGs) clusters with communication delays. The strategy involves establishing a twolayer communication network to regulate the voltage/frequency of all distributed generators (DGs) within the MG cluster to predefined reference values while ensuring consistency in incremental costs across individual MGs. Furthermore, a multi-step predictive controller is designed, where delay information in the controller is replaced by the latest predictions, enabling proactive compensation for delays. Stability analysis of the closed-loop AC MG clusters is conducted and the response matching condition is derived between the second and tertiary levels. Finally, realtime simulations on an OPAL-RT platform are performed for AC MG clusters, validating the robustness of the proposed control method against communication delays.

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.

This paper proposes a distributed cooperative control strategy for cyber-physical microgrids in a distributed sparse network with communication delays by using predictive control theory, which enables each distributed generator (DG) unit to achieve voltage restoration. In the proposed control strategy, we first design a primary droop-free model predictive controller to make the output voltage track its nominal set points timely, with the neighbor-based error information a secondary distributed coordinated predictive controller is then proposed to actively compensate the general communication delays for cyber-physical microgrids caused by low-bandwidth communication networks. Sufficient conditions, in terms of communication network connectivity and control gains for the system stability are derived by using the tools of special matrix theory and algebraic graph theory. The proposed control protocols are fully distributed and can be implemented through a sparse communication network and thus, satisfy the plug-and-play feature of the future smart grid. The effectiveness of the control strategy in compensating communication delays is also verified by real-time simulation experiments in OPAL-RT on a test microgrid.