Prescribed-performance based finite-time adaptive fuzzy control for PV inverter in islanded systems

Abstract

This paper investigates the problem of smoothing power control for photovoltaic (PV) inverter in islanded systems. In order to optimize the power control performance of an islanded PV inverter, a novel finite-time adaptive fuzzy control method with prescribed-performance control (PPC) is presented. Therein, the unmodeled parts in the dynamic model of a PV inverter is considered and approximate them by fuzzy logic systems, which reduce the dependence of the control effect on model accuracy. Moreover, adaptive control solves the problem of uncertainty of the model parameters and further increases the accuracy of the proposed controller. In addition, PPC is introduced to ensure the DC voltage tracking error converges within a limited bound, while the addition of a second-order sliding mode differentiator solves the differential expansion problem of backstepping method, and compensates the filtering error introduced by the compensation signal. Finally, the finite-time stability of the proposed method is proved based on Lyapunov stability theory, guaranteeing the convergence of the tracking error in finite-time. The effectiveness of the proposed control method is compared in the simulation.