A New Robust Control Strategy for a Wind Energy Conversion System Based on a T-S Fuzzy Model

Abstract

This paper discusses the design of a robust fuzzy Maximum Power Point Tracking (MPPT) control for a variable speed Wind Energy Conversion System (WECS) powered by a Permanent Magnet Synchronous Generator (PMSG). In fact, The main objective of this research work is to ameliorate the energy conversion efficiency of the WECS in spite the existence of a time-varying wind and model parameter uncertainties, by appropriately regulating the duty cycle of a boost converter used to control the studied device.  For this purpose, the Takagi–Sugeno (T-S) fuzzy model with parametric uncertainties is exploited for a fuzzy representation of the nonlinear WECS. Next, a T-S reference model relying on the MPPT algorithm is proposed to rapidly calculate the reference signals. Then, a fuzzy controller is developed to compute the duty cycle needed to ensure a robust tracking and a fast convergence to the maximum power for different wind speed changes. Afterward, the stability analysis of the closed-loop control system is proven by the Lyapunov theory and the H∞ performance. Besides, the controller gains are well determined by solving a Linear Matrix Inequality (LMI) problem. Finally, the robustness and the effectiveness of the suggested fuzzy control scheme are confirmed through both simulation results and experimental tests.