Distributed Secondary Control for DC Microgrids With Time-Varying Communication Delays: A Networked Predictive Control Scheme

With the rapid development of cyber-physical microgrids (MGs) and distributed generations (DGs), the distributed secondary control scheme becomes a key component of the MGs' control framework. However, the introduction of communication networks inevitably brings about time delays. Against this backdrop, this article proposes a distributed networked predictive control (DNPC) strategy for DC MGs suffering from time-varying communication delays. The proposed strategy can regulate the DG's voltage to the desired value and optimize each DG's generation cost simultaneously. Explicitly, the multistep predictor generates predictions for both local nodes and neighbor DGs, using the pseudo-prediction-enabled method. Thus, the delayed information in control protocols can be replaced by the latest predictions, so as to realize the active compensation for delays. Furthermore, the analysis of the stability of the closed-loop MG system is presented to ensure the generality of the DNPC strategy. Finally, the efficiency of the proposed control system against the time-varying delay effect is verified by comprehensive experiments in a DC MG containing a wind turbine generator.