Distributed Fault-Tolerant Voltage/Frequency Synchronization in Autonomous AC Microgrids

Abstract

This paper proposes two new distributed fault-tolerant control (FTC) algorithms for the restoration of voltage and frequency in autonomous inverter-interfaced AC microgrids (MGs). The proposed control schemes give fault-tolerance capability to the system against different potential faults in sensors and actuators. In the first algorithm, a distributed adaptive fault-tolerant method is employed to compensate for the potential sensor faults. Then, to address both sensor and actuator faults simultaneously, a distributed H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> protocol is employed to guarantee the voltage and frequency synchronization for the closed-loop system. In the design of these algorithms, there is no need to know the amplitude or any quantitative information about fault signals. Additionally, there is no restriction on the number of faulty units. Finally, to evaluate the performance of the proposed distributed cooperative fault-tolerant control algorithms, simulation studies are carried out on a test MG system, including several distributed generation (DG) units in MATLAB/Simulink environment and also the results are compared with several previously-reported methods. Simulation results and comparison with previous works reveal the effectiveness and accuracy of the proposed method in regulating MG voltage and frequency and providing accurate proportional active power-sharing.