Power Control of the Wind Turbine for Low Wind Speed Abderrahmen MECHTER*, Karim KEMIH*, Malek GHANES** * L2EI Laboratory, Electrical Department, Jijel University, BP 98, 18000 Jijel, Algeria. ** ECS-ENSEA, Cergy pontoise France Abstract — In this paper, we present a control strategy in order to optimize the power produced by the wind turbine. This strategy allows the calculation of a control law basing on the study of the stability of nonlinear continuous systems and the second method of Lyapunov. We have two parts to be controlled. In the mechanical part, the control law is used to optimize the rotational speed of wind turbine for low wind speed. In the electrical part, the control law is designed to optimize the electrical produced power. Keywords: Wind Energy, Doubly fed induction generator (DFIG), System stability, stator-flux-oriented vector. I. INTRODUCTION Wind energy produced from the wind force is an efficient, powerful and sustainable means of production. It has the advantage of being cleaner, safer and quicker to implement. This energy produced current using wind turbine from the kinetic energy of moving air like a nuclear reactor, a hydroelectric dam or a coal fired power station, but the environmental impacts on are not the same. Captured by a wind turbine, the wind's kinetic energy is converted into electricity using a generator. In this paper we will use the Doubly Fed Induction Generator (DFIG) which is the most used generator in the wind energy sector. The paper aims to optimize the produced electrical power. The control system is composed of two parts. In the first part the control law allows to the mechanical speed of the turbine to follow the variations of the wind. In the second part the control law must allow the power produced to follow its optimized value calculated from the mechanical speed of the turbine. Many previous studies had addressed the problem of optimizing the produced power by the wind turbine. In reference [1] was used the fuzzy-PI control to optimize the power. In reference [2], a sliding mode controller has been proposed. Reference [3] proposes an adaptive feedback linearization controller. In reference [4] an LQG controller for a linearised model of the wind turbine has been used. In reference [5] a robust fuzzy controller is developed. Reference [6] proposes a cascaded nonlinear controller for a VSWT to optimize the power. In reference [7] a hierarchical control structure is adopted to optimize the rotor speed and the produced electrical power. Reference [8] presents direct power control using classical PI regulators. Indirect power control using Sliding Mode controller has been used in [9]. In reference [10] a hybrid controller composed of several LPV controllers has been used. This paper is organized as follows. In section II the description and the modeling of the wind turbine are presented. In section III is shown the control method proposed in [11], this approach will be applied to optimize the power. In section VI simulation results on 300 kW wind turbine are presented. II. SYSTEM DESCRIPTION AND MODELING Fig. 1. Structure of the wind turbine system. Like it is presented in Fig.1, the wind turbine is composed of a wind rotor, a gear system and a generator. The wind rotor includes the blades for converting the wind's kinetic energy into mechanical energy, the gear system adapts to rotor speed to that of the generator and the generator converts mechanical energy to electricity for distribution. The energy captured by the wind rotor is given by, 鶏 痛 噺"系 椎 岾 怠 態 貢講迎 態 懸 戴 峇┻""""" """""""" """""(1)" Where, 貢 is the air density “ "計訣【兼 戴 .”, R is the blade length “兼.”, v represents the wind speed “兼【嫌.”. 系 椎 , is the power coefficient, it depends on the tip speed ratio 岫膏岻 and the pitch angle of the blades"岫紅岻."It is given by [12], 系 椎 岫膏┸ 紅岻 噺 ど┻のなどひ 岾ななは 岾 怠 碇袋待┻待腿庭 伐 待┻待戴泰 庭 典 袋怠 峇 伐 ど┻ね紅 伐 の峇 結 貸態怠磐 迭 敗甜轍┻轍添破 貸 轍┻轍典天 破 典 甜迭 卑 髪 ど┻どどはぱ膏┻ (2) Where, 膏噺 眺定 禰 塚 ┻"" " """"""""""""""""""(3)" Where,"硬 痛 is the mechanical angular speed of the turbine “堅欠穴【嫌結潔.”. The mechanical torque on the axis of the generator is given by, 系 陳勅頂 噺 怠 弔 系 痛 噺 怠 弔 牒 禰 定 禰 噺 怠 弔 待┻泰寵 妊 諦訂眺 鉄 塚 典 定 禰 ┻ (4) 懸 系 痛 硬 痛 硬 陳勅頂 " 系 陳勅頂 " 系 勅陳 " 硬 陳勅頂 追勅捗 " WIND ROTOR G E A R B O X GENERATOR 鶏 Proceedings of The first International Conference on Nanoelectronics, Communications and Renewable Energy 2013 498 ICNCRE ’13 ISBN : 978-81-925233-8-5 www.edlib.asdf.res.in Downloaded from www.edlib.asdf.res.in