Robust reliable fault tolerant control of islanded microgrids using augmented backstepping control

Abstract

This study proposes a novel fault tolerant voltage control method considering actuator faults and disturbances by using the backstepping control augmented by a new differentiator for islanded microgrids (MGs). Existing voltage control methods are designed based on the ideal condition that the distributed generations' actuators work healthily with the assumption of the absence of faults and disturbances, whereas MGs are exposed to the actuator faults including partial loss of effectiveness and biased faults. The proposed controller robustly regulates the MG voltages irrespective of the actuator faults. In contrast to existing methods, the controller has considered both actuator faults and loads with harmonic/interharmonic currents, which does not need to know the exact model of faults and frequency of harmonic and interharmonic of MG loads. This feature enables the MG to work properly, even at the lowest level, instead of the system completely collapsing. Therefore, it improves the reliability of the MG system. The MATLAB/SimPowerSystems toolbox has verified the validity of the proposed fault tolerant control method. Compared with effective methods, both the theoretical and simulation results show that the proposed method has better, robust, resilient, acceptable, and desirable performance, with respect to the unknown faults, actuator faults, non-linear loads, and disturbances.