Fractional Order Control with Super Twisting Observer for AC Microgrid

In this paper, a fractional-order continuous control with a modified super twisting disturbance observer (STDO) for a microgrid (MG) is proposed. Transient accuracy under finite-time control is a challenging issue in Islanded MG with strong disturbance rejection. sliding mode control (SMC) with conventional Sliding surface design exhibits asymptotic response with chattering contamination in the control signal. If the terminal surface is used for finite-time control, singularity and chattering problem may occur. In order to achieve chattering free finite time response with no singularity problem, fractional second-order continuous control (FSCC) is proposed with STDO. In this paper, FSCC is primarily designed to improve transient response with finite-time control. Next, STDO is utilized to achieve strong robustness against disturbance with comprehensive chattering elimination by adding a fractional term. To capitalize on optimal control effort, event-triggering control is implemented. Stability proof and event trigger conditions are derived using rigorous Lyapunov based analysis. The efficacy of the proposed controller is tested under MATLAB/Simulink.