Fuzzy Sliding Mode controls of Active and Reactive Power of a DFIG and Variable Speed Wind Energy conversion (original) (raw)

Abstarct In this paper an indirect vector control using fuzzy sliding mode control is proposed for a double-fed induction generator (DFIG), applied for a wind energy conversion system in variable speed. The objective is to independently control the active and reactive power generated by the DFIG, which is decoupled by the orientation of the flux. The sliding mode control finds its strongest justification for the problem concerning the use of a robust nonlinear control law for the model uncertainties. As far as the fuzzy mode control is concerned, it aims at reducing the chattering effect. The obtained results show the increasing interest of such control in this system. In this study, fuzzy sliding-mode control (FSMC) method, which is one of the active control algorithms, has been applied for a double-fed induction generator (DFIG). The chattering effect, the major disadvantage of conventional sliding-mode controller, has been removed by introducing FSMC without losing the robustness against parametric uncertainties, modeling inaccuracies and varying dynamic loads. For realizing the intelligent pitch controller, fuzzy sliding mode control, which combines fuzzy sliding mode control and self-organizing modifier, is proposed. 1.Introduction In recent years, there has been an evolution of wind electrical energy production. This source of energy has developed importantly considering the diversity of the exploitable zones and the relatively beneficial cost [1]. Now most wind turbines are equipped with a double-fed induction generator (DFIG) due to noticeable advantages: the variable speed generation (±30% around the synchronous speed), the decoupled control of active and reactive powers, the reduction of mechanical stresses and acoustic noise, the improvement of the power quality, and the low cost [2]. In the literature on DFIG control, different techniques have been used, among them indirect vector control with a PI controller. This technique offers some advantages: practical implementation, protection against the DFIG currents at high intensity, and operation of the DFIG as an active filter [3]. However, this technique of control loses its robustness and performance during the exposure of the DFIG to some constraints, such as the effects of parameter uncertainties (caused by heating, saturation, etc.) and the speed variation disturbance. In addition to these drawbacks, there is also the effect of coupling between the active and the reactive power [4]. To ensure the robustness and good performance of the indirect vector control using a PI controller, several approaches have been recently proposed. In [5], the authors proposed to optimize the gains of PI controllers by the genetic algorithm. In [6] and [7], the authors proposed an adaptive control with fuzzy and neuro-fuzzy logic to adjust the gains of PI controllers. Other approaches were adopted to change the PI controllers for other controllers, namely polynomial RST based on pole placement theory and linear quadratic Gaussian [4], sliding mode [8], second-order sliding mode [9], and fuzzy logic [10].