Power maximization of an asynchronous wind turbine with a variable speed feeding a centrifugal pump T. Ouchbel a,⇑ , S. Zouggar a , M.L. Elhafyani b , M. Seddik a , M. Oukili a , A. Aziz a , F.Z. Kadda a a University Mohammed 1er, School of Technology Oujda, Laboratory of Electrical Engineering and Maintenance (LEEM), BP, 473, 60000, Morocco b University Mohammed 1, National School of Applied Sciences Oujda, Morocco article info Article history: Available online 23 October 2013 Keywords: Self-excited induction generator Centrifugal pump Induction motor MPPT Static converter SVC abstract This article focuses on the study of a pumping system compound of a wind turbine, a self-excited induc- tion generator (SEIG), an induction motor (IM), and a centrifugal pump (CP), which aims to ensure the water pumping in optimum conditions regardless the wind speed. As a first step, a study in the steady and dynamic state to determine the control law is examined. As a second step, and so as to achieve a maximum energy flow we have proposed a Maximum Power Point Tracking (MPPT) algorithm based on a static converter SVC. As a final step, experimental and simulation results are discussed to show the reliability of the system proposed. Ó 2014 Published by Elsevier Ltd. 1. Introduction Due to the exhaustion increase of conventional energy and the degradation of environmental conditions, the continuous develop- ment of power generators dedicated to remote sites driven by renewable energy resources such as wind, solar, geothermal, bio- mass, and hydro are considered to replace conventional resources [1]. Wind energy is considered as the most practical and adopted among all renewable energies, because its available in most sites, it consisted to convert kinetic energy into a useful form of energy such as mechanical or electrical. One of the main applications that requires the use of the wind turbines is the water pumping [2–4], especially when the photovoltaic energy is penalized by its low yield and its high cost. Several types of wind turbines are used for autonomous production of electricity in the windiest sites such as: machine brushless, per- manent magnet, synchronous, asynchronous, and variable reluc- tance. Self-excited induction generator (SEIG) is the most replied for applications in low and medium power through its electric- ity production with lesser cost, simplicity of operation, con- struction brushless and eases of maintenance. Self excitation of SEIG is done directly by connecting a capacitor bank to the terminals of the stator [5–8]. Many researchers have discussed in permanent and a dynamic study the self-excited generator driven by a turbine powering a load (resistive, inductive, capacitive, and induction motor). Other works have focused on architectures and methods for maximizing the power, among them, the ones based on the fuzzy logic, neural network, etc. [9-15]. In the present work, we are interested, in the first time, to a the- oretical analysis of a wind electric pumping system, where a wind turbine is coupled to a SEIG of a 1.5 kW which directly supplies an induction motor IM, which is coupled to a pump CP. Simulation and practical results have been presented and dis- cussed to validate the performance of the proposed system. In the second part we have developed a new strategy of the maximization (MPPT) based on a static converter SVC, whose goal is to get a maximum energy flow in rural areas where the wind speed vary in large proportions. 2. Pumping system description Several wind electric pumping systems exist, but the most used is: a wind rotor with three blades coupled to a SEIG, whose magne- tization is provided by capacitor banks that feeds directly the IM, which is attached to the pump. Given the random nature of the wind causing the instability of the self-excited generator, and the problem of the moto-pump disconnection (induction motor con- nected to a pump) require the adjustment of the excitation capac- ity, whose purpose is to keep the ignition of the SEIG whatever is the wind speed (Fig. 1). The capacity of the global excitation used in this system, is divided into two parts: a fixed capacity to ensure a minimum exci- tation of SEIG, and other variable capacity realized by using the SVC. 0196-8904/$ - see front matter Ó 2014 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.enconman.2013.08.063 ⇑ Corresponding author. E-mail addresses: Ced_ouchbel@yahoo.fr (T. Ouchbel), zouggar@est.univ-oujda. ac.ma (S. Zouggar), m_elhafyani@yahoo.fr (M.L. Elhafyani). Energy Conversion and Management 78 (2014) 976–984 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman