A Distributed Prescribed-Time Control for Islanded AC Microgrid With Unknown Disturbances

Convergence speed of the frequency and voltage of islanded AC microgrid is important for the improvement of power quality. Therefore, a novel distributed prescribed-time (Di-PT) control methodology is developed to achieve this objective, which is composed of the regular output feedback and prescribed scaling function to accelerate the convergence process. Compared with the previously reported fixed-time control method, the upper bound of the convergence time (UB-CT) of the designed Di-PT control can be set explicitly and flexibly with much less conservativeness to evade the complicated inequality derivation of the Lyapunov-based convergence analysis. Its UB-CT does not require any calculation of control parameters and initial values. The designed Di-PT secondary control adopts a dual-layer architecture to decouple communication delays and unknown disturbances, such as hardware interferences and cyber attacks on the actuator. Through rigorous real-time simulation conducted on the RT-Unit platform, the superior performance of the designed control methodology has been demonstrated in terms of the improvement of power quality and disturbance robustness.