Modeling, Control and Design of Wind Energy Systems

The course offers a broad introduction to the engineering principles underlying the operation of wind turbines, as well as their design. The course is organized in the following five main modules: " Introduction: introduction to wind energy, and overview of wind energy systems and wind turbines; the wind resource and its characteristics; anatomy of a modern wind turbine; wind turbine components; electrical aspects. " Wind turbine aerodynamics: overview of rotor aerodynamics; one-dimensional momentum theory and Betz limit; wake swirl; airfoils; blade element momentum theory, dynamic inflow; unsteady corrections, blade tip and hub losses, dynamic stall, stall delay and three-dimensional effects; deterministic and stochastic wind models. " Dynamics and aeroservoelasticity: rigid and elastic flapping and lagging blade; the rotor as a filter, aerodynamic damping, flutter, limit cycle oscillations; loads; stability analysis; aeroservoelastic models of wind turbines; aeroservohydroelastic models for off-shore applications. " Wind turbine control: overview and architecture of wind turbine control systems; on-board sensors; supervisory control; regulation strategies; trimmers, load-reducing control, dampers; load and wind observers. " Wind turbine design: overview of design criteria and certification guidelines; aerodynamic design; structural design; design and choice of sub-systems and components.

After successfully completing the course, students will have an understanding of all main physical processes underlying the energy conversion process from wind. In addition, they will be able to apply their knowledge for giving qualitative explanations of key phenomena and for making some relevant quantitative predictions. For example, students will be able to analyze wind turbine performance and dynamics response, and to demonstrate the main strategies used for controlling these machines over their complete operating range. A specific goal of the course is to provide students with a multidisciplinary vision on the physics of wind energy systems, and to make them able to apply the explained methods to relevant problems. A particular emphasis will be placed on design, so that students will be able to evaluate the effects of design choices on the economics of wind energy, as well as on its environmental and social impacts.

Grading is based on a written exam, of a duration 90 min. Students should demonstrate their knowledge of the principal topics of the course, including wind turbine aerodynamics, aeroelasticity, regulation & control, simulation and design. The exam is composed of about 10-15 questions, each one worth a certain number of points, for a total of 100 points. Questions will include multiple-choice answers, open questions and exercises. Detailed instructions on the exam will be given both at the beginning and at the end of the course. A review lecture will be offered at the end of the course to highlight the main concepts and help students prepare for the exam. No aids are allowed during the exam, i.e no notes nor calculators, PCs, smartphones, etc.

Basic knowledge in engineering mechanics and aerodynamics.

• Course material will be provided by the instructor. Additional recommended literature: " T. Burton, N. Jenkins, D. Sharpe, E. Bossanyi, Wind Energy Handbook, Wiley, 2011. " J. F. Manwell, J.G. McGowan, A.L. Rogers, Wind Energy Explained, Theory, Design and Application, Wiley, 2012.

The course includes teaching lectures, which cover all theoretical content of the course and that are delivered with a teacher-centered style. The lectures are delivered with the help of slides, which include text, equations, figures, sketches and occasionally movies, as necessary in order to explain specific concepts or physical processes. Relevant examples from real-life wind energy applications will be given, whenever necessary or useful. The lecturer will annotate the slides or use the blackboard to help clarify some specific aspects, as necessary to ensure clarity and completeness of exposition. Review of background material is offered at the beginning of the course, to ensure that all students have the necessary knowledge and terminology. The course also includes exercise sessions, whose role is to consolidate and deepen the understanding of topics presented in the teaching lectures. Exercise sessions are typically initiated with a short review (given by the teacher with the help of dedicated slides) of the theory or methods explained in the lecture sessions. After the review, exercise sessions are continued with student-centered work, where students solve practical problems (for example dealing with the formulation of regulation strategies, the assessment of the vibratory behavior of a rotor, or the analysis of its performance) using computer programs. Students are encouraged to use their own individual learning methods, and to take advantage of the exercise sessions to reinforce and ease the understanding of the course main topics.

All course content is described and explained in self-contained lecture notes and support material, which are made available to the students at the beginning of the course. The course material covers also the exercise sessions, and it is complemented by computer programs and all necessary data.