Recent Advances, Challenges and Solutions in Wind Turbine and Wind Farm Advanced Control, Fault Diagnosis and Fault Tolerant Control

Organisers

  • Silvio Simani
  • Vicenç Puig
  • Hamed Badihi
  • Paolo Castaldi
  • Amin Hajizadeh
  • Peter Fogh Odgaard
  • Ron J. Patton
  • Horst Schulte
  • Youmin Zhang

Speakers

  • Silvio Simani, University of Ferrara, Italy
  • Vicenç Puig, Universitat Politècnica de Catalunya, Barcelona, Spain
  • Ron J. Patton, University of Hull, United Kingdom
  • Yanhua Liu, University of Hull, United Kingdom
  • Horst Schulte, University of Applied Sciences Berlin (HTW), Germany
  • Peter F. Odgaard, Goldwind Energy, Hinnerup, Denmark
  • Youmin Zhang, Concordia University, Canada
  • Paolo Castaldi, University of Bologna, Italy
  • Amin Hajizadeh, Aalborg University, Esbjerg, Denmark
  • Hamed Badihi, Nanjing University of Aeronautics and Astronautics, Jiangsu, China

Summary

The motivation for this workshop comes from a real need to have an overview about the challenges of fault diagnosis, fault tolerant control and advanced control solutions for very demanding systems, such as wind turbines and wind farm systems, which require reliability, availability, maintainability, and safety over power conversion efficiency. These topics have begun to stimulate research and development in the wide control community particularly for these installations that need a high degree of “sustainability” (i.e. tolerance with respect to possible fault). Note that this topic represents a key point mainly for offshore wind turbines with very large rotors, since they are characterised by challenging modelling and control problems, as well as expensive and safety critical maintenance works. In this case, a clear conflict exists between ensuring a high degree of availability and reducing maintenance times, which affect the final energy cost. On the other hand, wind turbines have highly nonlinear dynamics, with a stochastic and uncontrollable driving force as input in the form of wind speed, thus representing an interesting challenge also from the modelling point of view. Suitable advanced control methods, as well as fault diagnosis and fault tolerant control strategies, can provide a sustainable optimisation of the energy conversion efficiency over wider than normally expected working conditions. Moreover, a proper mathematical description of the wind turbine system should be able to capture the complete behaviour of the process under monitoring, thus providing an important impact on the control design itself. In this way, the control scheme could guarantee prescribed performance, whilst also giving a degree of “tolerance” to possible deviation of characteristic properties or system parameters from standard conditions, if properly included in the wind turbine model itself. The most important developments in advanced controllers for wind turbines are addressed, and open problems in the areas of modelling of wind turbines are also outlined. The workshop aims also to present and compare different schemes and solutions applied to nonlinear benchmark examples and real installations.

 

Programme

Introduction to the Workshop Sessions and Broad Areas of Condition Monitoring, Health Management, Fault Diagnosis and Sustainable Control, Silvio Simani

This talk provides a general introduction and opening remarks regarding the background, objectives and aims of the tutorial workshop, followed by an introduction to condition monitoring, fault detection and diagnosis (FDD), and fault-tolerant control (FTC); motivations, concepts, history, as well as existing and future developments are also addressed.


Introduction to Wind Turbine Modelling, Advanced Control, Fault Diagnosis and Fault Tolerant Control, Vicenç Puig

The systems under investigation will be introduced, by describing their characteristics, their categories, and their components, together with some global statistics that highlight the importance of the discussed topics. Then, several realistic benchmark systems are detailed that represent high-fidelity simulators of a single wind turbine and of a wind farm, respectively. They rely on the analytical description of the system behaviours, and provide also the models of typical fault cases.


Modelling and Robust Control Applications to Wind Turbine Systems, Peter Fogh Odgaard

As it is shown in the previous talk, wind turbines are complex dynamic systems forced by stochastic wind disturbances, as well as gravitational, centrifugal, and gyroscopic loads. Since their aerodynamics are nonlinear, wind turbine modelling and control are thus challenging tasks. Moreover, accurate models should contain many degrees of freedom to capture the most important dynamic effects. Therefore, the design of control algorithms for wind turbines should account for these complexities. However, these algorithms must capture the most important turbine dynamics without being too complex and unwieldy. The main purpose of this talk is thus to give examples of viable and practical designs of modelling and robust control schemes with application to wind turbine benchmark model.


Condition Monitoring and Health Management in Wind Turbines, Youmin Zhang

Starting with an overview of the most common faults in wind turbines, this presentation will discuss the major challenges and opportunities in real-time condition monitoring of wind turbines. It will present a detailed review on the currently available techniques and tools for condition monitoring and health management in wind turbines, followed by new and emerging cutting-edge techniques in this area. The presentation will cover all possible techniques including signal-based, knowledge-based and model-based fault detection and diagnosis (FDD) techniques, with emphasis on their application in wind turbines.


Fault Diagnosis for Wind Turbine Systems, Paolo Castaldi

This talk describes the main fault diagnosis algorithms applied to wind turbine systems. These techniques can be used for both condition monitoring purposes and fault diagnosis, in order to provide the information required by the fault tolerant control module. Model-based and data-driven strategies are summarised, which relies on measured as well as estimated variables.


Fault Tolerant Control for Wind Turbine Systems, Silvio Simani and Ron J. Patton

This talk presents the fault tolerant control algorithms applied to wind turbine systems. They are based on the signal correction principle, which means that the control system is not modified since the inputs and outputs of the baseline controller are compensated according to the estimated faults. The fault tolerant control algorithms recalled in this talk can rely on the fault diagnosis design addressed in the previous talk. Passive and active fault tolerant control systems are also discussed and compared, in order to highlight the achievable performances and the complexity of their design procedures. Controller reconfiguration mechanisms are also considered, which are able to guarantee the system stability and satisfactory performance.


Load mitigation in wind turbine systems based on fault estimation and fault tolerant control, Yanhua Liu and Ron J. Patton

Offshore wind turbines suffer from blade and tower asymmetrical loading, leading to enhanced structural fatigue. As well as asymmetrical loading, different faults (pitch system faults etc.) can occur simultaneously, causing degradation of load mitigation performance.  Individual pitch control (IPC) can achieve rotor asymmetric load mitigation, but this is accompanied by an enhancement of pitch movements leading to the increased possibility of pitch system faults, which exert negative effects on the IPC performance. The scenario of asymmetrical load mitigation is analogous to the FTC problem because the action of rotor bending (e.g. caused by unsteady wind loading) can itself be considered as a fault effect. The combined effects of asymmetrical blade and tower bending together with pitch sensor faults are considered as a “co-design” problem to minimize performance and fatigue deterioration and enhance wind turbine sustainability. “Fault effects” acting in the pitch actuation, rotor blade and tower systems are studied within a combined individual pitch control-based load mitigation and FTC system, focused on a comparison of different baseline control schemes.


Wind Power Plant Grid Integration for Future Power Systems, Horst Schulte

The talk will give an overview about control concepts and design methods for wind power plants under the perspective of grid support by auxiliary services. Continuous increase of renewable energy power plants requires their integration as active control units for grid stabilization and forming. In addition, the reduction of conventional energy producers causes more disturbances and parts of harmonics in the electrical power systems, which lead to a higher variation of the frequency and voltage. These new challenges require a systematic robust model-based design of renewable energy power systems, especially of wind power plants. For example, the fast power tracking of wind power plants for frequency stabilization makes it necessary to consider several performance criteria for multivariable controller design. In this course, LMI based methods are theoretically introduced and used for typical frequency control problems for network operation.


Control of Wind Power System During Grid Faults, Amin Hajizadeh

The talk considers the limitations of active power and reactive power injection to the grid during voltage faults. In fact, during the voltage fault in distribution systems, a decrease in voltage magnitude at the grid-connected converter is occurs. In this case, the current controllers to avoid overloading the converter limit the power that wind power system can supply to the grid during voltage fault.


Modelling of a Wind Turbine Using Noncausal Modelling Techniques, MathWorks

Model-Based Design is an efficient and cost-effective way to develop controls, signal processing, mechatronics, and other embedded systems. Rather than relying on physical prototypes and textual specifications, Model-Based Design uses a system model as an executable specification throughout development. It supports system- and component-level design and simulation, automatic code generation, and continuous test and verification. This talk is focused firstly on the so-called Model-Based Design and aims at presenting an up-to-date state of the art in this important field. Secondly, it develops a Model-Based Design for wind turbine systems. Mathematical formulations and numerical implementations for different components of wind turbine systems are highlighted with Simscape language.


Condition Monitoring and Fault Diagnosis in Wind Turbines: Past, Present, and Future, Youmin Zhang

This presentation will discuss the major challenges and opportunities in real-time condition monitoring of wind turbines. It will present a detailed review on the currently available techniques and tools for condition monitoring and health management in wind turbines, followed by new and emerging cutting-edge techniques in this area. The presentation will cover all possible techniques including signal-based, knowledge-based and model-based FDD techniques with emphasis on their application in wind turbines. Lastly, several case studies will be shown, and the presentation will be closed with a discussion on the open problems and future directions in this area.


Fault-Tolerant Control in Wind Turbines: Past, Present, and Future, Hamed Badihi

This presentation starts by briefly recalling and summarising the classifications and objectives of control at both individual wind turbine and entire wind farm levels; covering the wind turbine performance control and fatigue load control, as well as wind farm power quality control and power dispatch control. The presentation will then emphasize motivation, new control objectives and challenges regarding FTC in wind turbines and wind farms, followed by a detailed review on currently available techniques, as well as new and emerging state-of-the-art techniques in this area. Lastly, the presentation will be closed with a discussion on the open problems and future directions in this area.


Summary, Discussion, Open Problems, Future Issues, and Feedback,  Silvio Simani, Ron J. Patton, and Peter Fogh Odgaard

This talk summarises and discusses the obtained results, the main achievements of the workshop, and suggests some future investigations about the discussed topic.