1st Edition

Wind Energy Systems Control Engineering Design

    632 Pages 375 B/W Illustrations
    by CRC Press

    Presenting the latest developments in the field, Wind Energy Systems: Control Engineering Design offers a novel take on advanced control engineering design techniques for wind turbine applications. The book introduces concurrent quantitative engineering techniques for the design of highly efficient and reliable controllers, which can be used to solve the most critical problems of multi-megawatt wind energy systems.

    This book is based on the authors’ experience during the last two decades designing commercial multi-megawatt wind turbines and control systems for industry leaders, including NASA and the European Space Agency. This work is their response to the urgent need for a truly reliable concurrent engineering methodology for the design of advanced control systems. Outlining a roadmap for such a coordinated architecture, the authors consider the links between all aspects of a multi-megawatt wind energy project, in which the wind turbine and the control system must be cooperatively designed to achieve an optimized, reliable, and successful system.

    Look inside for information about the QFT Control Toolbox for Matlab, the software developed by the author to facilitate the QFT robust control design (see also the link at codypower.com).

    The textbook’s big-picture insights can help students and practicing engineers control and optimize a wind energy system, in which large, flexible, aerodynamic structures are connected to a demanding variable electrical grid and work automatically under very turbulent and unpredictable environmental conditions. The book covers topics including robust QFT control, aerodynamics, mechanical and electrical dynamic modeling, economics, reliability, and efficiency. It also addresses standards, certification, implementation, grid integration, and power quality, as well as environmental and maintenance issues.

    To reinforce understanding, the authors present real examples of experimentation with commercial multi-megawatt direct-drive wind turbines, as well as on-shore, offshore, floating, and airborne wind turbine applications. They also offer a unique in-depth exploration of the quantitative feedback theory (QFT)—a proven, successful robust control technique for real-world applications—as well as advanced switching control techniques that help engineers exceed classical linear limitations.


    Broad Context and Motivation

    Concurrent Engineering: A Road Map for Energy

    Quantitative Robust Control

    Novel CAD Toolbox for QFT Controller Design



    Part I: Advanced Robust Control Techniques: QFT and Nonlinear Switching

    Introduction to QFT

    Quantitative Feedback Theory

    Why Feedback?

    QFT Overview

    Insight into the QFT Technique

    Benefits of QFT

    MISO Analog QFT Control System


    QFT Method (Single-Loop MISO System)

    Design Procedure Outline

    Minimum-Phase System Performance Specifications

    J LTI Plant Models

    Plant Templates of Pι(s), P( j_i )

    Nominal Plant

    U-Contour (Stability Bound)

    Tracking Bounds BR(jω) on the NC

    Disturbance Bounds BD(jωi)

    Composite Boundary Bo(jωi)

    Shaping of Lo(jω)

    Guidelines for Shaping Lo(jω)

    Design of the Prefilter F(s)

    Basic Design Procedure for a MISO System

    Design Example 1

    Design Example 2

    Template Generation for Unstable Plants

    Discrete Quantitative Feedback Technique


    Bilinear Transformations

    Non-Minimum-Phase Analog Plant

    Discrete MISO Model with Plant Uncertainty

    QFT w-Domain DIG Design


    Basic Design Procedure for a MISO S-D Control System

    QFT Technique Applied to the PCT System

    Applicability of Design Technique to Other Plants

    Designing L(w) Directly

    Diagonal MIMO QFT


    Examples and Motivation

    MIMO Systems—Characteristics and Overview

    MIMO QFT Control—Overview

    Nonsequential Diagonal MIMO QFT (Method 1)

    Sequential Diagonal MIMO QFT (Method 2)

    Basically Noninteracting Loops

    MIMO QFT with External (Input) Disturbances

    Non-Diagonal MIMO QFT


    Non-Diagonal MIMO QFT: A Coupling Minimization Technique (Method 3)

    Coupling Elements

    Optimum Non-Diagonal Compensator

    Coupling Effects

    Quality Function of the Designed Compensator

    Design Methodology

    Some Practical Issues

    Non-Diagonal MIMO QFT: A Generalized Technique (Method 4)


    Translating Matrix Performance Specifications

    Comparison of Methods 3 and 4

    QFT for Distributed Parameter Systems



    Generalized DPS Control System Structure

    Extension of Quantitative Feedback Theory to DPS

    Modeling Approaches for PDE


    Nonlinear Switching Control Techniques


    System Stability under Switching




    Part II: Wind Turbine Control

    Introduction to Wind Energy Systems


    Birth of Modern Wind Turbines

    Market Sizes and Investments

    Future Challenges and Opportunities

    Standards and Certification for Wind Turbines


    Standards: Definition and Strategic Value

    Standards: Structure and Development

    Certification of Wind Turbines

    General Concepts

    Wind Turbine Control Objectives and Strategies


    Control Objectives

    Control Strategies

    Control System

    Aerodynamics and Mechanical Modeling of Wind Turbines


    Aerodynamic Models

    Mechanical Models

    Electrical Modeling of Wind Turbines


    Electrical Models

    Power Electronic Converters

    Power Quality Characteristics

    Wind Farms Integration in the Power System

    Advanced Pitch Control System Design


    QFT Robust Control Design

    Nonlinear Switching Multi-Objective Design

    Nonlinear Robust Control Design for Large Parameter Variation

    Experimental Results with the Direct-Drive Wind Turbine TWT-1.65


    Variable-Speed Direct-Drive Torres Wind Turbine Family

    Torres Wind Turbine Pitch and Rotor Speed Control Results

    Wind Farm Grid Integration: Torres Wind Turbine Results

    Voltage Dip Solutions: Torres Wind Turbine Results

    Blades Manufacturing: MIMO QFT Control for Industrial Furnaces


    Composite Materials

    Industrial Furnace Description

    Furnace Model

    Estimation of Furnace Parameters

    MIMO QFT Controller Design

    Experimental Results

    Smart Wind Turbine Blades


    General Description

    Some History

    Offshore Wind Energy: Overview


    History of Offshore Platforms

    Offshore Wind Farms

    Offshore Floating Wind Turbines

    Airborne Wind Energy Systems


    Overview of Airborne Wind Energy Systems

    Eagle System


    Appendix A: Templates Generation

    Appendix B: Inequality Bound Expressions

    Appendix C: Analytical QFT Bounds

    Appendix D: Essentials for Loop Shaping

    Appendix E: Fragility Analysis with QFT

    Appendix F: QFT Control Toolbox: User’s Guide

    Appendix G: Controller Design Examples

    Appendix H: Conversion of Units



    Answers to Selected Problems




    Dr. Mario García-Sanz is Professor at Case Western Reserve University (CWRU), Ohio, the Milton and Tamar Maltz Professor in Energy Innovation, and Director of the Wind Energy and Control Systems Center at CWRU.  As Senior Advisor for the President of the M.Torres Group and Professor at the Public University of Navarra, he played a central role in the design and field experimentation of advanced multi-megawatt wind turbines for industry. Dr. García-Sanz held visiting professorships at the Control Systems Centre, UMIST (UK, 1995); at Oxford University (UK, 1996); at the Jet Propulsion Laboratory NASA-JPL (California, 2004); and at the European Space Agency ESA-ESTEC (The Netherlands, 2008). 

    He holds 20 industrial patents, has done more than 40 large research projects for industry and space agencies, and is author or coauthor of more than 150 research papers, including the books “Quantitative Feedback Theory: Theory and Applications”, Taylor & Francis (2006), and “Wind Energy Systems: Control Engineering Design”, Taylor & Francis (2012). 

    Dr. García-Sanz is Subject Editor of the International Journal of Robust and Nonlinear Control, a member of IFAC and IEEE Technical Committees, and served as NATO/RTO Lecture Series Director and as Guest Editor of international journals (Robust control, QFT control, Wind turbine control, Spacecraft control). He was awarded the IEE Heaviside Prize (UK) in 1995 and the BBVA research award (Spain) in 2001.  Professor García-Sanz's main research interest focuses on bridging the gap between advanced control theory and applications, with special emphasis in Energy Innovation, Wind Energy, Space, Environmental and Industrial Applications.

    Garcia-Sanz and Houpis, who both have extensive expertise in major projects in North America and Europe, describe the latest science and technology in wind turbines … . The text includes a link to a free download for the CAD tool they utilize …
    —SciTech News, Vol. 66, September 2012