Distributed Observer-Based H∞ Fault-Tolerant Control for DC Microgrids With Sensor Fault

摘要

Disturbances, uncertainties, noises and device faults commonly exist in microgrids and often undermine the system stability. To meet these challenges, robust control methods have been recently employed in microgrids systems. In this paper, an active fault-tolerant control scheme is proposed for DC islanded microgrids subjected to sensor fault and external disturbance. Firstly, a distributed H-infinity observer is designed to estimate the uncorrupted voltage and current with high accuracy. Then, an observer based state feedback controller is proposed to ensure stability of voltage regulation for the system. A consensus based control layer in the secondary level is provided to realize current sharing. For the plug-and-play operation of DC microgrids, decentralized parameters design approaches for the observer and controller are both discussed. Finally, simulation studies and experiments are carried out on a DC microgrid system to evaluate the effectiveness of the proposed fault-tolerant control scheme. The simulation and experiment results show that compared with previous works, the proposed observer based control strategy can significantly improve the reliability and resilience of DC microgrid systems.