INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH O. Gam et al., Vol.8, No.3, September, 2018 Robust Control Strategies on the Optimization of a Wind Turbine Pumping System Olfa Gam *, Riadh Abdelati * ‡ , Mahamadou Abdou Tankari **, Mohamed Faouzi Mimouni*, Gilles Lefebvre** * Department of Electrical Engineering, Unit ESIER, National School of Engineers of Monastir, University of Monastir, Tunisia ** CERTES Laboratory, Paris Est Crteil, 61, Avenue du Gnral De Gaulle, 94010, Creteil Cedex (phdolfa2015@gmail.com, riaabdelati@yahoo.fr, mahamadou.abdou-tankari@u-pec.fr) ‡ Corresponding Author; Second Author, University of Monastir, Av. Ibn El Jazzar Skanes (5019), Tunisia, Tel: +216 55 854232, Received: 30.04.2018 Accepted:04.07.2018 Abstract- Wind Turbine water pumping system (WTWPS) has been an important area of research during these last years. The control of WTWPS has attracted researchers from different fields to improve the effectiveness of water pumping systems. In this paper, we focus on the study of a pumping system composed by a wind turbine, permanent magnet synchronous generator, an induction motor (IM), and a centrifugal pump. Our purpose is to keep the water pumping in optimum conditions and maximize the extracted wind power. In a first step, we analyze the operation of WTWPS at variable speed with pitch angle control to ensure the required power without mechanical failure. The principle source and the dynamic load were connected via a direct current bus. On the other hand, to achieve the feeding of the moto-pump with a good quality of electrical energy, an analytic equation is developed which adapts the set point rotation speed of induction machine regardless the state of wind velocity. A nonlinear DTC control strategy is adopted based on space vector pulse width modulation. Simulation results are performed in MATLAB environment and show the performance and capability of the proposed control scheme of WTWPS. . Keywords Wind energy, Optimization, Water pumping, Direct torque control, Energy optimization. 1. Introduction In the last decades, the necessity of optimizing of water exploitation and energy resources has become an essential issue and it will be more vital in the future [1]. Due to the exhaustion increase of human consumption, the limited reserves on conventional energy resources such as natural gas, coal and oil ) and the degradation of environmental conditions, renewable sources (such as biomass, solar photovoltaic, wind and hybrid forms of energy) have become an alternative solution to reduce the dependence on fossil fuels to generate electricity [2]. For instance, in a remote agricultural area, the demand of electrical energy supply systems is increasing for desalination, water pumping and supplying isolated dwellings with electricity. Among all renewable energy resources, the wind energy is considered as the most promising generator thanks to its availability in most remote areas [3]. Moreover, pumping water presented one of the applications that mostly needs the use of wind turbines. Because, when a wind turbine is powering a water pumping system, it can easily establish a natural relationship between water requirement and the wind power availability [4]. WTWPS are particularly suitable with their different mechanical, electrical and electronic components for water pumping. Several types of WT are used for isolated regions. Previous studies indicated that variable speed turbines are much more efficient in energy capture compared with constant speed turbine [5]. Several control strategies are developed by researchers in order to improve and make WTWPS more efficient and reliable. Many other works, focus on new techniques to improve the output controllability of wind energy systems. In this context, several methods have been proposed to extract a maximum power