Design of Controls to Attenuate Loads in the Controls Advanced Research Turbine

2004 ◽  
Vol 126 (4) ◽  
pp. 1083-1091 ◽  
Author(s):  
Alan D. Wright ◽  
Mark J. Balas
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Control Method ◽  
Maximum Energy ◽  
Drive Train ◽  
Control Input ◽  
Pitch Control ◽  
Additional Control ◽  
Bending Modes ◽  
Turbine Speed

The wind industry seeks to design wind turbines to maximize energy production and increase fatigue life. To achieve this goal, we must design wind turbines to extract maximum energy and reduce component and system loads. This paper applies modern state-space control design methods to a two-bladed teetering-hub upwind machine located at the National Wind Technology Center. The design objective is to regulate turbine speed in region 3 (above rated wind speed) and enhance damping in several low-damped flexible modes of the turbine. The controls approach is based on the Disturbance Accommodating Control method and provides accountability for wind-speed disturbances. First, controls are designed with the single control input rotor collective pitch to stabilize the first drive-train torsion as well as the tower first fore-aft bending modes. Generator torque is then incorporated as an additional control input. This reduces some of the demand placed on the rotor collective pitch control system and enhances first drive train torsion mode damping. Individual blade pitch control is then used to attenuate wind disturbances having spatial variation over the rotor and effectively reduces blade flap deflections caused by wind shear.

A novel wind speed estimator-integrated pitch control method for wind turbines with global-power regulation

Energy ◽  
2017 ◽  
Vol 138 ◽  
pp. 816-830 ◽  
Author(s):  
Dongran Song ◽  
Jian Yang ◽  
Mei Su ◽  
Anfeng Liu ◽  
Zili Cai ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Control Method ◽  
Pitch Control ◽  
Global Power ◽  
Power Regulation ◽  
Speed Estimator

scholarly journals A Simplified Morphing Blade for Horizontal Axis Wind Turbines

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Weijun Wang ◽  
Stéphane Caro ◽  
Fouad Bennis ◽  
Oscar Roberto Salinas Mejia
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Annual Average ◽  
Average Wind Speed ◽  
Pitch Control ◽  
Average Wind

The aim of designing wind turbine blades is to improve the power capture ability. Since rotor control technology is currently limited to controlling rotational speed and blade pitch, an increasing concern has been given to morphing blades. In this paper, a simplified morphing blade is introduced, which has a linear twist distribution along the span and a shape that can be controlled by adjusting the twist of the blade's root and tip. To evaluate the performance of wind turbine blades, a numerical code based on the blade element momentum theory is developed and validated. The blade of the NREL Phase VI wind turbine is taken as a reference blade and has a fixed pitch. The optimization problems associated with the control of the morphing blade and a blade with pitch control are formulated. The optimal results show that the morphing blade gives better results than the blade with pitch control in terms of produced power. Under the assumption that at a given site, the annual average wind speed is known and the wind speed follows a Rayleigh distribution, the annual energy production of wind turbines was evaluated for three types of blade, namely, morphing blade, blade with pitch control and fixed pitch blade. For an annual average wind speed varying between 5 m/s and 15 m/s, it turns out that the annual energy production of the wind turbine containing morphing blades is 24.5% to 69.7% higher than the annual energy production of the wind turbine containing pitch fixed blades. Likewise, the annual energy production of the wind turbine containing blades with pitch control is 22.7% to 66.9% higher than the annual energy production of the wind turbine containing pitch fixed blades.

Control method for ventilated supercavitating vehicle considering planing avoidance and stability

2018 ◽  
Vol 233 (3) ◽  
pp. 957-968
Author(s):  
Seonhong Kim ◽  
Nakwan Kim
Keyword(s):  
Control Method ◽  
Ventilation System ◽  
Stability Loss ◽  
Vehicle Stability ◽  
Control Input ◽  
Supercavitating Vehicle ◽  
Additional Control ◽  
Avoidance Control ◽  
And Performance ◽  
Stability Issues

In this study, we focus on realizing planing avoidance control for a ventilated supercavitating vehicle while considering stability issues. A ventilated supercavitating vehicle can control the size of a cavity by blowing gas into the cavity. By controlling the cavity size, planing can be prevented in advance. However, the vehicle loses its stability because of the growth of the cavity. Additional control input is determined to prevent “stability loss” based on linear stability analysis while considering ventilation system dynamics. The proposed controllers are applied to a supercavitating vehicle model, and numerical simulations are performed to analyze the physical feasibility and performance of the designed controllers. The results show that the proposed control methods can maintain vehicle stability during maneuvering operations and can eliminate planing.

Nonlinear Systems Analysis and Control of Variable Speed Wind Turbines for Multiregime Operation

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
Greg Semrau ◽  
Sigitas Rimkus ◽  
Tuhin Das
Keyword(s):  
Wind Speed ◽  
Nonlinear Systems ◽  
Wind Turbines ◽  
Control Input ◽  
Variable Speed ◽  
Wind Speeds ◽  
Speed Regulation ◽  
The Stability ◽  
Control Feedback ◽  
Operating Regimes

The key control problems associated with variable speed wind turbines are maximization of extracted energy when operating below the rated wind speed, and power and speed regulation when operating above the rated wind speed. In this paper, we develop a nonlinear systems framework to address these problems. The framework is used to visualize and analyze the equilibria of the wind turbine as its operating regimes and controllers change. For both below rated and above rated wind speeds, we adopt nonlinear controllers, analyze the stability property of the resulting equilibria, and establish the criterion for switching between control regimes. Further, the regions of attraction of the resulting equilibria are determined, and the existence of a common region of attraction, which allows stable switching between operating regimes, is shown. The control input maintains continuity at the point of switching. We next provide a method for blade pitch modulation to control rotor speed at high wind speeds. Through Lyapunov stability analysis, we prove stability of the equilibria in the presence of the two independently functioning torque- and pitch-control feedback loops. Simulation results are presented and the controller is compared with existing works from the literature.

The Modeling and Simulation of Wind Turbines and the Design of Pitch Control System

2011 ◽  
Vol 347-353 ◽  
pp. 2323-2329
Author(s):  
Zhi Chao Lan ◽  
Lin Tao Hu ◽  
Yin Xue ◽  
De Liang Zen
Keyword(s):  
Control System ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Active Power ◽  
Internal Model Control ◽  
Pitch Control ◽  
Constant Pitch ◽  
Model Control

An increasing number of large wind turbines with a variable-speed variable pitch control mechanism are developed to improve the response speed of wind turbines and get maximum active power .Designing a reasonable pitch control system requires both a good control scheme and a more accurate wind turbine model. Base on the analysis of wind turbines’ principle, a local linearization model of wind turbine is built by using linearization method of small deviation in this paper. The model’s inputs are the data of wind speed and pitch angle, and the output is the active power. The accuracy of the model is verified by studying the active power output of wind turbine under different circumstances in which the pitch angle changes with a constant wind speed and the wind speed changes with a constant pitch angle. At the same time, this paper provides pitch control program based on internal model control after analyzing the disadvantages of PID pitch controller. When the wind speed is beyond the rating, the active power can be limited reasonably around the power rating of wind turbines by adjusting the pitch angle.

Nonlinear Control of Variable-Speed Wind Turbines for Generator Torque Limiting and Power Optimization

2006 ◽  
Vol 128 (4) ◽  
pp. 516-530 ◽  
Author(s):  
B. Boukhezzar ◽  
H. Siguerdidjane ◽  
M. Maureen Hand
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Maximum Energy ◽  
Current Control ◽  
Dynamic State ◽  
Power Coefficient ◽  
Control Input ◽  
Variable Speed ◽  
Power Extraction ◽  
Speed Estimator

To maximize wind power extraction, a variable-speed wind turbine (VSWT) should operate as close as possible to its optimal power coefficient. The generator torque is used as a control input to improve wind energy capture by forcing the wind turbine (WT) to stay close to the maximum energy point. In general, current control techniques do not take into account the dynamical and stochastic aspect of both turbine and wind, leading to significant power losses. In addition, they are not robust with respect to disturbances. In order to address these weaknesses, a nonlinear approach, without wind speed measurement for VSWT control, is proposed. Nonlinear static and dynamic state feedback controllers with wind speed estimator are then derived. The controllers were tested with a WT simple mathematical model and are validated with an aeroelastic wind turbine simulator in the presence of disturbances and measurement noise. The results have shown better performance in comparison with existing controllers.

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