Download or read book Individual Blade Pitch and Disturbance Accommodating Control of Floating Offshore Wind Turbines written by Hazim Namik and published by . This book was released on 2012 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Floating wind turbines offer a feasible solution for going further offshore into deep waters. However, using a floating platform introduces additional motions that must be taken into account actively or passively. Therefore, the control system becomes an important component in controlling these motions. In this work, the development, implementation, and simulation of multi-objective state feedback and disturbance accommodating controllers applied on the three main floating concepts are described. The three concepts are the barge, tension leg, and spar-buoy floating platforms. These controllers utilise individual blade pitching to create asymmetric aerodynamic loads in addition to the symmetric loads created by collective blade pitching to increase the platform restoring moments. Simulation results, according to design load case 1.2 of the IEC 61400-3 standard for offshore wind turbines, show that state feedback controllers improve the performance relative to a collective blade pitch gain scheduled proportional-integral controller in terms of power and rotor speed regulation as well as reducing tower fore-aft and side-side bending loads. However, the magnitude of the improvements depends on the dynamics of each platform, its responsiveness to individual blade pitching and sensitivities to external wind and wave disturbances. Furthermore, interesting physical phenomena, such as the platform roll to pitch coupling caused by the controller, are identified. Disturbance accommodating controllers for rejecting wind speed perturbations further improve rotor speed regulation and reduce tower fore-aft bending loads except on the barge platform; the barge platform motion is dominated by incident waves and therefore rejecting wind speed perturbations has no noticeable impact. Wave moment disturbance rejection is also investigated but in a limited case study. While the approach taken can theoretically cancel the effects of incident wave moments, practically, the required actuation force cannot be generated by the wind turbine blades. Furthermore, using the blades for rejecting wave moments increases the tower bending due to the load path of the restoring moment through the tower. Out of the three investigated platforms, the tension leg platform with a disturbance accommodating controller has the best overall performance with fatigue loads close or less than that of an onshore wind turbine. The other two platforms, in their current design form, experience large tower fore-aft bending loads that would prevent them from being deployed in rough sea conditions.

Download or read book Blade Pitch Control for Wind Turbine Load Reductions written by Wai Hou (Alan) Lio and published by Springer. This book was released on 2018-03-01 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the use of blade-pitch control and real-time wind measurements to reduce the structural loads on the rotors and blades of wind turbines. The first part of the thesis studies the main similarities between the various classes of current blade-pitch control strategies, which have to date remained overlooked by mainstream literature. It also investigates the feasibility of an estimator design that extracts the turbine tower motion signal from the blade load measurements. In turn, the second part of the thesis proposes a novel model predictive control layer in the control architecture that enables an existing controller to incorporate the upcoming wind information and constraint-handling features. This thesis provides essential clarifications of and systematic design guidelines for these topics, which can benefit the design of wind turbines and, it is hoped, inspire the development of more innovative mechanical load-reduction solutions in the field of wind energy.

Download or read book Wind Energy written by Mathew Sathyajith and published by Springer Science & Business Media. This book was released on 2006-03-14 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growing energy demand and environmental consciousness have re-evoked human interest in wind energy. As a result, wind is the fastest growing energy source in the world today. Policy frame works and action plans have already been for- lated at various corners for meeting at least 20 per cent of the global energy - mand with new-renewables by 2010, among which wind is going to be the major player. In view of the rapid growth of wind industry, Universities, all around the world, have given due emphasis to wind energy technology in their undergraduate and graduate curriculum. These academic programmes attract students from diver- fied backgrounds, ranging from social science to engineering and technology. Fundamentals of wind energy conversion, which is discussed in the preliminary chapters of this book, have these students as the target group. Advanced resource analysis tools derived and applied are beneficial to academics and researchers working in this area. The Wind Energy Resource Analysis (WERA) software, provided with the book, is an effective tool for wind energy practitioners for - sessing the energy potential and simulating turbine performance at prospective sites.

Download or read book Handbook of Wind Power Systems written by Panos M. Pardalos and published by Springer Science & Business Media. This book was released on 2014-01-15 with total page 839 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind power is currently considered as the fastest growing energy resource in the world. Technological advances and government subsidies have contributed in the rapid rise of Wind power systems. The Handbook on Wind Power Systems provides an overview on several aspects of wind power systems and is divided into four sections: optimization problems in wind power generation, grid integration of wind power systems, modeling, control and maintenance of wind facilities and innovative wind energy generation. The chapters are contributed by experts working on different aspects of wind energy generation and conversion.

Download or read book Active Blade Pitch and Hull Based Structural Control of Floating Offshore Wind Turbines written by Eben J. Lenfest and published by . This book was released on 2021 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mitigation of Wind Turbine Vortex Interaction Using Disturbance Accommodating Control written by and published by DIANE Publishing. This book was released on with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Independent Blade Pitch Controller Design for a Three Bladed Turbine Using Disturbance Accommodating Control Preprint written by and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DAC-based IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both of the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs.

Download or read book Remote Sensing of Atmospheric Conditions for Wind Energy Applications written by Charlotte Bay Hasager and published by MDPI. This book was released on 2019-05-24 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue “Atmospheric Conditions for Wind Energy Applications” hosts papers on aspects of remote sensing for atmospheric conditions for wind energy applications. Wind lidar technology is presented from a theoretical view on the coherent focused Doppler lidar principles. Furthermore, wind lidar for applied use for wind turbine control, wind farm wake, and gust characterizations is presented, as well as methods to reduce uncertainty when using lidar in complex terrain. Wind lidar observations are used to validate numerical model results. Wind Doppler lidar mounted on aircraft used for observing winds in hurricane conditions and Doppler radar on the ground used for very short-term wind forecasting are presented. For the offshore environment, floating lidar data processing is presented as well as an experiment with wind-profiling lidar on a ferry for model validation. Assessments of wind resources in the coastal zone using wind-profiling lidar and global wind maps using satellite data are presented.

Download or read book Fatigue oriented Data driven Individual Pitch Control Strategies of Wind Turbines written by David Collet and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Horizontal axis wind turbines are the leading figure of the wind energy industry and is becoming a mature technology. Even though wind energy is globally trending, the yearly number of wind turbines installed is weakening in some countries, due to the reduction of economic subventions. In the context of global warming and energetic transition, it is of primal importance to optimize the levelized cost of wind energy, in order to make it economically competitive against fossil source of energies and allow wind energy to less rely on economic subventions. The control of wind turbines can strongly contribute to answer this issue.Individual blade Pitch Control (IPC) of wind turbines can allow to modify the aerodynamic properties of the rotor and regulate the unbalanced loads due to skewed wind in the rotor plane. Regulating these unbalanced loads can help in alleviating the fatigue damage of the rotating components of the turbine, such as the blades. On the other hand, IPC is known to induce oscillating loads on the blade pitch actuators and increase their excursions, which induces additional fatigue damage on the blade pitch actuators and blade bearings. Therefore, IPC can have positive effects on the fatigue damage of some components of the turbine, while having negative effects on others. For an efficient optimization of the levelized cost of wind energy, it is necessary that an IPC be optimized, in order to efficiently manage the trade-off between the fatigue damage of various components of a turbine.To address this issue, a fatigue cost function is defined as a weighted sum of wind turbine components fatigue damage, and possibly economic parameters. An IPC regulator must thus be designed in order to minimize this fatigue cost. However, the optimization of fatigue is a challenging task, as the fatigue damage expression does not suit standard forms. It is shown several times in this thesis that standard control strategies are limiting the potential reduction of the fatigue cost expectancy. While combining several standard control strategies designed with different parameters could allow significant reductions of the fatigue cost expectancy, compared to standard IPC control strategies with fixed parameters. The challenge addressed in this thesis is thus to adapt the parameters of standard IPC control strategies, in order to efficiently reduce the fatigue cost expectancy of wind turbines. Two approaches are thus developed in order to address this issue.The first one consists in approximating the fatigue cost function with a fatigue-oriented cost function, thanks to a data-driven identification based on parameterized quadratic forms. This fatigue-oriented cost function used in an optimal control problem allows to efficiently parameterize a standard optimization problem, which approximate the fatigue cost optimization problem around its optimum. Therefore, the fatigue-oriented optimal control problem allows efficient reductions of the fatigue cost expectancy.Model Predictive Control (MPC) is a control strategy which allows to optimize a specified cost function, by solving on-line an optimal control problem. Then, an IPC MPC is derived based on the fatigue-oriented optimal control problem expression. These controllers are thus standard MPCs whose parameters are adapted for fatigue cost reduction. These controllers are then implemented in closed-loop with a simplified wind turbine model and showed great potential in reducing the fatigue cost expectancy, compared to an MPC with fixed parameters.The second approach is a framework where a supervisory layer selects the parameters of candidate controllers based on wind conditions, in order to efficiently minimize the wind turbine fatigue cost expectancy. A proof of concept made with a simple supervisory layer showed that significant reduction of the fatigue cost are already possible, which encourages to also develop this second approach further.

Download or read book Wind Turbine Control Systems written by Fernando D. Bianchi and published by Springer Science & Business Media. This book was released on 2006-09-07 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book emphasizes the application of Linear Parameter Varying (LPV) gain scheduling techniques to the control of wind energy conversion systems. This reformulation of the classical problem of gain scheduling allows straightforward design procedure and simple controller implementation. From an overview of basic wind energy conversion, to analysis of common control strategies, to design details for LPV gain-scheduled controllers for both fixed- and variable-pitch, this is a thorough and informative monograph.

Download or read book A Contribution to the Nonlinear Control of Floating Wind Turbines written by Cheng Zhang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Floating wind turbines allow the use of the abundant wind resource in ocean area and are considered as a promising solution of renewable energy. However, due to the additional dynamics (especially the platform pitch motion) introduced by the floating platform, the control of a floating wind turbine must take such pitch motion into consideration to stabilize the system meanwhile optimizing the power output. This work is dedicated to the nonlinear control of floating wind turbines in region III, this class of controllers requiring reduced knowledge of system modeling and parameter. The control objectives are to maintain the power output at its rated value, to reduce the platform pitch motion and to limit the fatigue load. Firstly, a simplified adaptive super-twisting is proposed. Then, by using collective blade pitch control, this algorithm and other adaptive high order sliding model algorithms are applied on a nonlinear floating wind turbine model. Secondly, a permanent magnet synchronous generator is supposed to be installed in the floating wind turbine. Both collective blade pitch control and generator torque control based on adaptive high-order sliding mode control are used to achieve the control objectives. Thirdly, individual blade pitch control combined with collective blade pitch control is employed. Such algorithm further reduces the fatigue load of blades. Finally, the proposed simplified adaptive super-twisting algorithm is validated on an experimental floating wind turbine set-up (with a spar-buoy platform) in a wave tank, and the control performances are evaluated versus linear control approaches such as gain-scheduled PI and linear-quadratic regulators.

Download or read book Wind Energy Systems written by Mario Garcia-Sanz and published by CRC Press. This book was released on 2012-02-02 with total page 635 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 links to a free download of QFTCT—a new interactive CAD tool for QFT controller design with MATLAB® that the authors developed with the European Space Agency. 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.

Download or read book Disturbance Accommodating Control Based Independent Blade Pitch Control Design on CART2 written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Turbine Collective and Individual Pitch Control Using Quantitative Feedback Theory written by Laura Wheeler and published by . This book was released on 2017 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Individual pitch control is a new technique in the field of wind turbine control, used to reduce the asymmetric mechanical loads on the blades of multi-megawatt turbines. Therefore, the mechanical fatigue is reduced and the lifetime of the turbine is extended. In this work, an individual pitch controller is developed for the National Renewable Energy Laboratory’s (NREL) 5 MW reference wind turbine. The individual pitch controller works along with a collective pitch controller, designed using the Quantitative Feedback Theory Control Toolbox in Matlab. The individual and collective pitch controllers are simulated using NREL’s computer-aided engineering tool for horizontal axis wind turbines, FAST. Simulations show that the addition of the individual pitch controller reduces the loads on the tilt and yaw turbine components (the nacelle and tower) at the 1p and 3p frequencies by half, and the loads on the blades at the 2p harmonic frequency, by almost half.

Download or read book Advances in Modelling and Control of Wind and Hydrogenerators written by Amir Ebrahimi and published by BoD – Books on Demand. This book was released on 2020-04-01 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid deployment of wind and solar energy generation is going to result in a series of new problems with regards to the reliability of our electrical grid in terms of outages, cost, and life-time, forcing us to promptly deal with the challenging restructuring of our energy systems. Increased penetration of fluctuating renewable energy resources is a challenge for the electrical grid. Proposing solutions to deal with this problem also impacts the functionality of large generators. The power electronic generator interactions, multi-domain modelling, and reliable monitoring systems are examples of new challenges in this field. This book presents some new modelling methods and technologies for renewable energy generators including wind, ocean, and hydropower systems.

Download or read book Model free Optimizing Control for Wind Energy Capture and Controls of Floating Wind Turbines written by Zhongyou Wu and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ramification of wind power generation critically depends on the reduction of its levelized cost of energy (LCOE), for which enhancing the energy capture and reducing the fatigue loads are two major pillars. Development of advanced control strategies for enhancing power capture and reducing the structural loads has become a primary aspect for the operation of individual turbines and the whole wind farm, offshore or onshore. This dissertation research aims to pursue investigations on advanced control strategies that cover both energy capture enhancement and load reduction: 1) extremum seeking based model-free control for enhancing wind turbine and wind farm energy capture with improved convergence, and 2) controls of floating offshore wind turbines (FOWT) with novel actuations. For wind turbine operation below the rated wind speed (i.e. Region 2), the primary control objective for variable-speed variable-pitch turbines is to optimize the generator torque for maximizing the energy capture. Extremum seeking control (ESC) has emerged as an appealing model-free Region-2 control method with much less dependency on turbine characteristics and wind speed measurement. However, the previous work of ESC Region-2 control with the rotor power feedback suffers from undesirable convergence due to wind fluctuation. An estimated power coefficient is proposed as the ESC objective function in order to reduce the sensitivity of the optimum seeking process to wind fluctuation. The hub-height free-stream wind speed is estimated with the nacelle anemometer measurement based on the so-called nacelle transfer function (NTF) derived between the nacelle anemometer and met-tower measurement. Also, an ESC integrated inter-region switching scheme is proposed to avoid the load increase associated with the ESC operation. FAST based simulation study shows that the proposed method achieves more robust convergence to wind fluctuation compared to the power feedback based ESC. For Region-2 control of wind farm operation, the Nested-Loop Extremum Seeking Control (NLESC) has demonstrated its effectiveness in enhancing energy capture at the farm level, however, its convergence speed has been highly limited by the delay of wake propagation between the upstream and downstream turbines as the dither signals for optimizing upstream turbines needs to be of much lower frequencies. In this dissertation research, the NLESC is enhanced with a predictor based delay compensation (DCNLESC), based on which the dither frequencies of upstream turbines can be retained at the level for individual turbine operation. The proposed scheme is validated with a three-turbine model in SimWindFarm. The research FOWT controls is conducted for tensioned-leg platform (TLP), and two novel actuation schemes are proposed for motion stabilization and load reduction: dynamic vibrations absorber (DVA) and active mooring line force control (AMFLC) with fishing line artificial muscle (FLAM) actuator. First proposed is to deploy the vertically operated DVAs at the spokes of TLP structure. Via the Lagrange’s equations, a control-oriented model of 11 degrees-offreedom (DOFs) is derived for the TLP-FOWT-DVA system, with which a linear quadratic regulator (LQR) is designed for stabilizing the platform pitch and roll motion. The LQR controller, turbine controller, as well as the DVA model are implemented in Simulink, which is coupled with the wind turbine model in FAST via a dedicated interface. Simulations are performed for 9 m/s and 18 m/s turbulent winds with different wind and wave directions. The simulation results show that the platform motion and tower loads in the lateral direction and mooring line tension load are significantly reduced, while the tower load in the fore-aft direction can be moderately reduced. For achieving the performance in platform motion stabilization and load reduction, the average power consumption of the DVA actuators is less than 0.27% of the wind turbine power generated during the simulated periods. As for the second concept of TLP-FOWT control, the FLAM actuator is proposed to be deployed to the junction between the mooring lines and TLP spokes, realizing AMLFC of TLP-FOWT. The FLAM actuator consists of multiple bundles of twisted nylon fishing lines, with the contracting and stretching forces induced by thermal actuation. A simulation model of the FLAM actuator is developed in Simulink, along with an interface to the mooring line model of TLP-FOWT in FAST. The dynamic model of the FLAM actuator is obtained with ANSYS simulation, and a control-oriented model is obtained for the FOWT platform motion. First, an LQR controller is implemented to validate the proposed framework. Then, based on the development of dynamic hybrid automata (DHA) model for the TLP-FOWT system with FLAM actuators, a hybrid model predictive controller is developed with the inclusion of information on incoming wind and wave. Simulation study shows that, with mild power consumption, the proposed AMLFC strategy can significantly reduce the platform roll motion and the tower-base side-side bending loads with little impact on the rotor speed and power output.

Download or read book Offshore Mechanics written by Madjid Karimirad and published by John Wiley & Sons. This book was released on 2018-05-07 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers theoretical concepts in offshore mechanics with consideration to new applications, including offshore wind farms, ocean energy devices, aquaculture, floating bridges, and submerged tunnels This comprehensive book covers important aspects of the required analysis and design of offshore structures and systems and the fundamental background material for offshore engineering. Whereas most of the books currently available in the field use traditional oil, gas, and ship industry examples in order to explain the fundamentals in offshore mechanics, this book uses more recent applications, including recent fixed-bottom and floating offshore platforms, ocean energy structures and systems such as wind turbines, wave energy converters, tidal turbines and hybrid marine platforms. Offshore Mechanics covers traditional and more recent methodologies used in offshore structure modelling (including SPH and hydroelasticity models). It also examines numerical techniques, including computational fluid dynamics and finite element method. Additionally, the book features easy-to-understand exercises and examples. Provides a comprehensive treatment for the case of recent applications in offshore mechanics for researchers and engineers Presents the subject of computational fluid dynamics (CFD) and finite element methods (FEM) along with the high fidelity numerical analysis of recent applications in offshore mechanics Offers insight into the philosophy and power of numerical simulations and an understanding of the mathematical nature of the fluid and structural dynamics with focus on offshore mechanic applications Offshore Mechanics: Structural and Fluid Dynamics for Recent Applications is an important book for graduate and senior undergraduate students in offshore engineering and for offshore engineers and researchers in the offshore industry.