Secure Recursive Estimator-Based Command Filtered Event-Triggered Control for Islanded AC Microgrids Under Deception Attacks

This article proposes a secure recursive estimator-based command filtered event-triggered control (EBCFETC) scheme for cyber-physical islanded AC microgrids (MGs) with unknown nonlinear loads under deception attacks. A discrete-time dynamic model of the islanded AC MG is given, and the voltage regulation problem is transformed into an output feedback tracking control issue. First, a secure recursive extended state estimator is designed to handle unknown nonlinear loads and estimate the immeasurable MG states under deception attacks. In particular, an upper bound on the estimation error covariance of the recursive estimator is obtained, and the real-time gain matrix is derived from the upper bound. Then, an EBCFETC strategy is developed by utilizing the backstepping technique, and an event-triggered mechanism is introduced to reduce the transmission frequency of control signals. The scheme guarantees that both the estimation error and the signals of the closed-loop system are bounded, and the tracking error converges to a small neighbourhood near zero. Finally, the simulation results verify the validity of the proposed EBCFETC method.