4826 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 56, NO. 12, DECEMBER 2009 Energetic Macroscopic Representation and Inversion-Based Control Illustrated on a Wind-Energy-Conversion System Using Hardware-in-the-Loop Simulation Alain Bouscayrol, Member, IEEE, Xavier Guillaud, Member, IEEE, Phillipe Delarue, and Betty Lemaire-Semail, Member, IEEE Abstract—Study of a wind-energy-conversion system (WECS) is a very attractive topic for students. The analysis of an entire WECS requires knowledge of different scientific fields, which are of interest for future engineers. In this paper, energetic macro- scopic representation is used to describe a complete WECS. This synthetic graphical tool yields a natural decomposition of the studied WECS with respect to physical laws. Moreover, a control scheme is easily deduced from this description using inversion-based rules. Thus, maximum-power point-tracking strategies and drive controls can be defined. The simulation of the studied WECS is directly transposed to MATLAB–Simulink. Moreover, a hardware-in-the-loop simulation of the WECS is studied using an actual induction generator and an electrical drive to simulate the wind turbine. This graphical methodology is used in the electrical engineering Masters degree at the University of Lille (France). Index Terms—Drive control, education, hardware-in-the-loop (HIL) simulation, wind energy. I. I NTRODUCTION R ENEWABLE energy is of growing interest [1], [2]. Many studies have been carried out in the last two decades, specifically on wind-energy-conversion systems (WECSs). Variable-speed controls increase the power extracted from the wind [3]. Power electronics and energy-storage elements are key issues in the future development of WECS [4]–[6]. Study of WECS is thus a promising and interesting area for education. First, this topic is very attractive in our depart- ments, which have seen a significant reduction in the number of students. Moreover, the study of an entire WECS requires different scientific fields, useful for future engineers. Finally, the development of renewable energy will require engineers with knowledge on this topic. However, such multidisciplinary Manuscript received April 11, 2007; revised January 5, 2009. First published February 3, 2009; current version published November 6, 2009. A. Bouscayrol, P. Delarue, and B. Lemaire-Semail are with the Laboratory of Electrical Engineering of Lille, University of Sciences and Technologies of Lille, 59655 Villeneuve d’Ascq, France (e-mail: Alain.Bouscayrol@univ- lille1.fr; Philippe.Delarue@univ-lille1.fr; Betty.Semail@polytech-lille.fr). X. Guillaud is with the Laboratory of Electrical Engineering of Lille, Ecole Centrale de Lille, 59651 Villeneuve d’Ascq, France (e-mail: Xavier. Guillaud@ec-lille.fr). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TIE.2009.2013251 studies are difficult to implement. Due to the complexity of WECS, only simulations are often used. Experimental skills have also to be developed, as noted in educational experiences on real-time drive controls [7]. Other approaches insist on the “learning by experimenting” [8] or remote interactive experiments [9] in teaching control engineering. Experimentation on complex mechanical parts is often impossible in educational laboratories [10]. Use of virtual load torque emulation [10] or hardware-in-the-loop (HIL) con- cepts [11]–[15] can avoid the need for costly and cumbersome mechanical parts. HIL simulation has already been used for teaching the control of robots [16]. Multidisciplinary systems are currently commonly studied using graphical descriptions like bond graphs [17], power- oriented graphs [18], power flow diagrams [19], and causal- ordering graphs [20]. All of these tools are also regularly used in education. Energetic macroscopic representation (EMR) has been specifically designed for the modeling and the control of large or highly coupled electromechanical systems [21]. EMR decomposes the system into natural interconnected elements according to the principles of physical causality [20], [22] and interaction [23]. This graphical tool has been successfully applied in research studies on hybrid vehicles, railway-traction systems [24], and WECSs [15], [21], [25]. In this paper, EMR is used to describe an entire WECS for teaching purpose in the electrical engineering Masters degree at the University of Lille. This paper has been derived from research experience. First, the WECS modeling is developed, then the whole control structure is obtained, using inversion rules. The simulation scheme of the WECS is directly trans- posed from EMR to MATLAB–Simulink. Moreover, this paper aims to develop student skills by applying theoretical concepts to real-time implementation. Thus, a HIL simulation of the WECS is deduced using an actual induction generator and a dc machine drive to simulate the wind turbine. II. STUDIED WECS A. Description of Studied WECS The studied system is composed of a wind turbine, a gearbox, a squirrel-cage induction machine, one back-to-back voltage- source converter (VSC), and a transformer connected to the grid 0278-0046/$26.00 © 2009 IEEE