Improvement of Power Quality Injected into the Grid by Using a FOSMC-DPC for Doubly Fed Induction Generator

Abstract

This research work deals with the design of a direct power control strategy (DPC) based on the fractionalorder sliding mode (FOSMC) theory for the doubly fed induction generator (DFIG). The novelty of this paper is the use of proportional derivative (PD) fractional order sliding surface that is constructed using Riemann-Liouville fractional derivative and its accurate representation with a transfer function. This make the whole control strategy simpler and more accurate. Also the study of the quality of the current injected into the grid is performed. The stability of DFIG is guaranteed by means of the Lyapunov function. In order to optimize the amount of electrical energy captured from the wind, the MPPT (Maximum Power Point Tracking) technique is adopted. The proposed controller forces the system to track the desired values of active and reactive powers. In addition, power ripples are restrained even if the DFIG is subjected to disturbances and parameter variations. Furthermore, a comparative study is conducted between the developed controller and other nonlinear methods that exist in the literature. The results obtained, under different wind profiles, confirm its robustness and superiority in terms of performance and quality of power injected into the grid. In terms of THD, our control strategy does not exceed 1.31%, on the contrary, the fuzzy logic DTC which is developed recently reaches 2.81%.

Performance analysis and enhancement of direct power control of DFIG based wind system

“…Consequently, one can derive the relationship between control configurations and the electrical voltages of the AC and DC sides of the inverter. The general topology of the two-level voltage source inverter (VSI) is shown in Figure 5 each inverter arm contains two electronic switches IGBT [25].…”