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 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 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 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 Disturbance Tracking and Blade Load Control of Wind Turbines in Variable speed Operation written by Karl A. Stol and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Distrubance Tracking and Blade Load Control of Wind Turbines in Variable Speed Operation written by and published by . This book was released on 2003 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A composite state-space controller was developed for a multi-objective problem in the variable-speed operation of wind turbines. Disturbance Tracking Control theory was applied to the design of a torque controller to optimize energy capture under the influence of persistent wind disturbances. A limitation in the theory for common multi-state models is described, which led to the design of a complementary pitch controller. The goal of the independent blade pitch design was to minimize blade root fatigue loads. Simulation results indicate an 11% reduction in fatigue damage using the proposed controllers, compared to a conventional torque-only design. Meanwhile, energy capture is almost identical, partly because of nonlinear effects.

Download or read book Design of State Space Based Control Algorithms for Wind Turbine Speed Regulation written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Control can improve the performance of wind turbines by enhancing energy capture and reducing dynamic loads. At the National Renewable Energy Laboratory, we are beginning to design control algorithms for regulation of turbine speed and power using state-space control designs. In this paper, we describe the design of such a control algorithm for regulation of rotor speed in full-load operation (region 3) for a two-bladed wind turbine. We base our control design on simple linear models of a turbine, which contain rotor and generator rotation, drivetrain torsion, and rotor flap degrees of freedom (first mode only). We account for wind-speed fluctuations using disturbance-accommodating control. We show the capability of these control schemes to stabilize the modeled turbine modes via pole placement while using state estimation to reduce the number of turbine measurements that are needed for these control algorithms. We incorporate these controllers into the FAST-AD code and show simulation results for various conditions. Finally, we report conclusions to this work and outline future studies.

Download or read book Design of Controls to Attenuate Loads in the Controls Advanced Research Turbine written by Alan Duane Wright and published by . This book was released on 2003 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Load Reducing Control for Wind Turbines written by Martin Shan and published by Fraunhofer Verlag. This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In wind turbine engineering, it is a well-known fact that mechanical loading of the structural components, as tower and blades, can be heavily influenced by means of control. This work provides a comprehensive discussion on systematic control design for active load reduction. A review of the established approaches for load reducing pitch control is given. The basic idea is to adjust the blade pitch angles to provide active damping of structural loads or to compensate for periodic load components. A survey on rating and cost of wind turbine structural components is given to sketch the potential impacts of control design on Cost-of-Energy. Special focus in a separate chapter is given to the major trade-off between load reductions and rating of the pitch actuator system. In the main part, a pragmatic approach to systematic control design by use of modern multi-variable control design methods is introduced. Linear models in combination with disturbance spectra are applied to allow for fast and transparent optimization of the controllers. Exemplarily, this hierarchical control design / controller tuning approach is demonstrated for two different types of load reducing pitch controllers.

Download or read book Linear Optimal Control of Wind Turbines in Region III written by Aliakbar Dabbaghmanesh and published by . This book was released on 2010 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing wind turbines to maximize energy production and increase fatigue life is a major goal of the wind industry. To achieve this goal, we should design wind turbines to extract maximum energy and reduce component and system loads. This thesis applies a linear quadratic regulator (LQR) pitch-control algorithm based on disturbance correction to a two-bladed teetering-hub upwind machine. The design objective is to regulate turbine speed in region three (above-rated wind speed) and to enhance damping in several low-damped flexible modes of the turbine. A PI controller and a LQR- DAC (disturbance accommodation controller) are designed for a typical wind turbine model. We show that the LQR-DAC controller performs better than the PI controller by reducing the overshoot and pitch angle fluctuations during full-load operation.

Download or read book Systematic Approach for PID Controller Design for Pitch regulated Variable speed Wind Turbines written by M. Maureen Hand (author) and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three regions of operation. This document focuses on controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is desired. The robust nature of the proportional-integral-derivative (PID) controller is illustrated, and optimal operating conditions are determined. Because numerous simulation runs may be completed in a short time, the relationship of the two opposing metrics is easily visualized.

Download or read book Design of Controls to Attenuate Loads in the Controls Advanced Research Turbine written by Alan Duane Wright and published by . This book was released on 2003 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pitch Control of Wind Turbine Through PID Fuzzy and Adaptive Fuzzy PID Controllers written by Silpa Baburajan and published by . This book was released on 2017 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: "As the penetration of the wind energy into the electrical power grid is extensively increased, the influence of the wind turbine systems on the frequency and voltage stability becomes more and more significant. Wind turbine rotor bears different types of loads; aerodynamic loads, gravitational loads and centrifugal loads. These loads cause fatigue and vibration in blades, which cause degradation to the rotor blades. These loads can be overcome and the amount of collected power can be controlled using a good pitch controller (PC) which will tune the attack angle of a wind turbine rotor blade into or out of the wind. Each blade is exposed to different loads due to the variation of the wind speed across the rotor blades. For this reason, individual electric drives can be used in future to control the pitch of the blades in a process called Individual Pitch Control. In this thesis work, an enhanced pitch angle control strategy based on fuzzy logic control is proposed to cope with the nonlinear characteristics of wind turbine as well as to reduce the loads on the blades. A mathematical model of wind turbine (pitch control system) is developed and is tested with three controllers -PID, Fuzzy, and Adaptive Fuzzy-PID. After comparing all the three proposed strategies, the simulation results show that the Adaptive Fuzzy-PID controller has the best performance as it regulates the pitch system as well as the disturbances and uncertain factors associated with the system."--Abstract.

Download or read book Experimental Study of Active and Passive Blade Pitch Control Strategies for Axial flow Marine Current Turbines written by Katherine D. Van Ness and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cost and reliability remain among the main barriers limiting widespread adoption ofriverine, estuarine, or ocean current turbine power generation. In particular, structural loads are significantly greater than for wind turbines with equivalent power output, which contributes to higher costs. Compounded with uncertainties about hydrodynamic loads, this can contribute to structural failure or excessive and expensive safety factors. Consequently, control strategies to mitigate structural loads and reduce cost are of considerable importance. Load reduction is of particular interest when currents exceed a certain threshold (i.e., theturbine-specific “rated speed”), and a control strategy is implemented to maintain a constant power output. Most fixed-pitch turbines will use a speed control strategy, increasing or decreasing the rotation rate to achieve the efficiency required for power regulation. However, these “overspeed” and “underspeed” control strategies correspond to large increases in thrust or torque, respectively, that require overdesigning the turbine blades or generator. Blade pitch control circumvents this trade-off, as decreased angles of attack simultaneously reduce thrust and torque. This does, however, require actuators to change blade pitch. While active pitch control is the conventional standard for wind turbines in these above-rated conditions, similar variable blade pitch mechanisms have not yet been uniformly adopted by marine current technology developers due to the higher cost of inspection, maintenance, and repairs relative to wind turbines. For this reason, passive adaptive blade pitch control, in which blades are designed to elastically deform under load without an actuator, sensor, or control logic, is conceptually attractive. Improved understanding of the loading associated with both speed and pitch control strategies is critical to optimizing a design for minimal cost and maximal reliability. Therefore, the overarching goal of this work is to experimentally investigate active and passive pitch control methods, characterize their potential for load reduction, and establish appropriate scaling relations for passive adaptive blades. The three underlying objectives supporting this goal are outlined below. The first objective is to demonstrate active blade pitch control in above-rated flow conditionsand compare the measured turbine loads to those observed with overspeed and underspeed control in order to develop our understanding of the trade-offs associated with each. To this end, we experimentally characterized power performance and turbine loading over a range of blade pitch settings and tip-speed ratios for a three-bladed axial-flow turbine. We then implemented a control strategy to maintain power output in time-varying currents using blade pitch control and compared the turbine performance under this control strategy to overspeed and underspeed control strategies for a fixed pitch turbine. The experiments were conducted with a laboratory-scale 0.45-m diameter turbine in an open channel flume with a 35% blockage ratio. During pitch characterization experiments, inflow velocity was maintained at 0.8 m/s with 4% turbulence intensity. During time-varying inflow experiments, currents varied from 0.7-0.8 m/s over a 20-minute period, while a proportional controller regulated either blade pitch or rotor speed, and we recorded turbine power output and turbine loads. In this velocity range, where turbine performance is independent of Reynolds number, we demonstrate that pitch control substantially reduces torque requirements relative to underspeed control and streamwise turbine loads relative to overspeed control. Additional tests were conducted for underspeed control and pitch control in a Reynolds-dependent regime with time-varying inflow between 0.4-0.5 m/s and 0.5-0.6 m/s. These cases suggest that blade pitch control could provide even greater benefits relative to speed control in small-scale applications. The second objective is to develop our understanding of passive adaptive blade fabricationand the effect of fiber orientation to inform a passive pitch control design. By tailoring the ply angle in a unidirectional carbon fiber blade, a desired twist can be induced in response to bending of the blade under load. In developing this form of passive adaptive control, a fundamental question is how to non-dimensionalize the fluid-structure interaction to make laboratory-scale experiments relevant to full-scale applications. To address these questions, we first conducted an experimental investigation into the effect of fiber angle on blade performance and blade deformation during turbine operation. The composite blades were fabricated with 0°, 2.5°, 5°, and 10° fiber orientations, where a positive fiber orientation results in a reduced angle of attack as load increases (i.e., a “pitch-to-feather” control strategy). Blades were tested in a recirculating flume at 0.7 m/s (Rec = 5.3 · 104 − 2.0 · 105) while measuring force and torque on the rotor. Simultaneously, a high-speed camera observed in-situ deflection and twist at the blade tip. Results show a greater reduction in CP and CT for blades with larger fiber orientations relative to the neutral blade set, while even small fiber orientations were observed to limit thrust at high tip-speed ratios. To explore the correct non-dimensional scaling for this physical process, we performed a set of Cauchyscaled experiments using blades with identical bend-twist couplings but different bending stiffness. These results demonstrate that the Cauchy number is a meaningful parameter for scaling passive adaptive current turbine blades and to model steady-state hydrodynamic and hydroelastic behavior. The third and final objective is to implement passive pitch control to develop our understandingof the trade-offs between speed, active pitch, and passive pitch control methods. Two passive blade pitch control strategies for the same lab-scale turbine were developed and tested experimentally in a recirculating flume. The goal of the control is to regulate mechanical power, while minimizing rotor loads, when flow conditions exceed the rated condition. Both strategies used the 5° fiber blade set from the aforementioned study. One control strategy combined passive adaptive blades with overspeed control (actuating rotational speed above the tip-speed ratio corresponding to peak efficiency) while the other combined passive adaptive blades with active pitch control (actuating blade pitch using motors at the blade root). Both strategies were implemented in linearly increasing inflow from 0.7 m/s to 0.8 m/s and compared to control strategies using rigid, aluminum blades under the same flow conditions. The passive adaptive blades combined with active pitch control show no improvement in steady-state load reductions relative to rigid blades used with active pitch control. However, the passive adaptive blades combined with overspeed control show reduced torque and only a 12% increase in thrust relative to the rated flow condition. This indicates that passive adaptive blades combined with overspeed control can be an effective strategy in currents above the rated flow speed, removing the need for an active pitch mechanism in some applications. In addition to measuring turbine loads, deflection and twist of the passive adaptive blades during experimental testing were observed using a high-speed camera to support our understanding of the bend-twist behavior during turbine operation over a range of flow speeds, rotation rates, and preset pitch angles. Overall, active and passive pitch control strategies for Region III are shown to offer significantload reductions in thrust and torque relative to rigid blade speed control strategies. While controller selection is discussed primarily relative to their associated loads, we discuss additional considerations including blade design, channel blockage, range and frequency of flow variation, and Reynolds-number. These discussions underline the value of future investigations into active and passive pitch control for smoothing high-frequency loads and scaling between lab- and full-scale passive adaptive rotors, among other work.

Download or read book Variable speed Wind Turbine Controller Systematic Design Methodology written by M. Maureen Hand and published by . This book was released on 1998 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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.