Invariant Set-Based DC Microgrid Decentralized Actuator Fault-Tolerant Control

Abstract

Faults and system failure components are primarily two causes of unstable or deteriorating control performance of power system. In this study, we present a novel approach to the decentralized restoration of large DC microgrids using fault-tolerant control (FTC). The microgrid achieves decentralization by partitioning into several smaller grids. Each independent grid views the actions of the other grids as an external disturbance. The malfunction of the controller is represented in the input matrix as a norm-bounded uncertainty. The disturbance impact is diminished due to the proposed invariant-set approach. The proposed control can address simultaneous failures in actuators with random placement and degradation levels. In a passive FTC system, when the defect cannot be detected (or the fault may not have been clearly addressed), the proposed technique is utilized. After the fault has occurred, it can be viewed as an uncertainty in system dynamics. The controller that stabilizes the system is obtained by solving iteratively bilinear matrix inequalities as linear matrix inequalities. In addition, this study presents and discusses positive outcomes of applying this method to a system of six interconnected DC microgrids in the event of multiple fault types. The proposed control successfully stabilizes the severe case of simultaneous actuator faults.

Keywords

• DC microgrid (MG)
• decentralized control
• fault-tolerant control
• invariant ellipsoid
• robust tracker