Design of State-Space-Based Control Algorithms for Wind Turbine Speed Regulation

2002 ◽  
Author(s):  
Alan D. Wright ◽  
Mark J. Balas
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
Degrees Of Freedom ◽  
Linear Models ◽  
Pole Placement ◽  
Control Algorithms ◽  
Speed Regulation ◽  
Full Load Operation ◽  
Turbine Speed ◽  
Speed Fluctuations

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.

Design of State-Space-Based Control Algorithms for Wind Turbine Speed Regulation

2003 ◽  
Vol 125 (4) ◽  
pp. 386-395 ◽  
Author(s):  
Alan D. Wright ◽  
Mark J. Balas
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
Degrees Of Freedom ◽  
Linear Models ◽  
Pole Placement ◽  
Control Algorithms ◽  
Simulation Code ◽  
Speed Regulation ◽  
Full Load Operation ◽  
Turbine Speed

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, drive train torsion, rotor flap (first mode only), and tower fore-aft degrees of freedom (DOFs). Wind-speed fluctuations are accounted for using Disturbance Accommodating Control (DAC). 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 algorithms. These controllers are incorporated into a simulation code and simulated for various conditions. Finally, conclusions to this work and future studies are outlined.

Design of Modern Controls for the Controlled Advanced Research Turbine (CART)

2003 ◽  
Author(s):  
Alan D. Wright ◽  
Mark J. Balas
Keyword(s):  
Degrees Of Freedom ◽  
Linear Models ◽  
Operating Conditions ◽  
Pole Placement ◽  
Control Algorithms ◽  
Energy Capture ◽  
Control Schemes ◽  
Full Load Operation ◽  
Turbine Speed ◽  
Speed Fluctuations

Control can improve the performance of wind turbines by enhancing energy capture and reducing dynamic loads. At the National Renewable Energy Laboratory, we are designing control algorithms for regulation of turbine speed and power using state-space control methods. In this paper, we describe the design of a control algorithm for regulation of rotor speed in full-load operation (region 3) for the Controlled Advanced Research Turbine (CART). This turbine is a two-bladed, teetering hub, upwind machine, adapted for testing a variety of control algorithms. We base our control design on simple linear models of a turbine, which contain rotor and generator rotation, drivetrain torsion, rotor flap, and tower fore-aft bending degrees of freedom. We account for wind-speed fluctuations using disturbance accommodating control (DAC). We show the capability of these control schemes to stabilize the modeled turbine modes via pole placement while using state estimation to reduce the required number of turbine measurements. We test these algorithms through simulation, incorporating them into two simulation codes and simulating the controlled system for various operating conditions. Finally, we report conclusions to this work and outline future studies.

Full-State Feedback Control of a Variable-Speed Wind Turbine: A Comparison of Periodic and Constant Gains

2001 ◽  
Vol 123 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Karl Stol ◽  
Mark Balas
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
State Feedback ◽  
State Feedback Control ◽  
Variable Speed ◽  
Horizontal Axis Wind Turbine ◽  
Speed Regulation ◽  
Significant Difference ◽  
Full State ◽  
Full State Feedback

An investigation of the performance of a model-based periodic gain controller is presented for a two-bladed, variable-speed, horizontal-axis wind turbine. Performance is based on speed regulation using full-span collective blade pitch. The turbine is modeled with five degrees-of-freedom; tower fore-aft bending, nacelle yaw, rotor position, and flapwise bending of each blade. An attempt is made to quantify what model degrees-of-freedom make the system most periodic, using Floquet modal properties. This justifies the inclusion of yaw motion in the model. Optimal control ideas are adopted in the design of both periodic and constant gain full-state feedback controllers, based on a linearized periodic model. Upon comparison, no significant difference in performance is observed between the two types of control in speed regulation.

Disturbance Observer Based Control Design for Wind Turbine Speed Regulation

2016 ◽  
Author(s):  
Yuan Yuan ◽  
Xu Chen ◽  
Jiong Tang
Keyword(s):  
Wind Turbine ◽  
Pid Controller ◽  
Disturbance Observer ◽  
Control Loop ◽  
Wind Fields ◽  
Model Mismatch ◽  
Model Based ◽  
Speed Regulation ◽  
Power Regulation ◽  
Turbine Speed

Disturbance observer based (DOB) control has been implemented in motion control to reject unknown or time-varying disturbances. In this research, an internal model-based disturbance observer (DOB) design combined with a PID type feedback controller is formulated for wind turbine speed and power regulation. The DOB controller facilitates model-based estimation and cancellation of disturbance using an inner feedback control loop. The disturbance observer combined with a compensator is further designed to deal with the model mismatch. The proposed method is applied to National Renewable Energy laboratory (NREL) offshore 5-MW wind turbine. Our case studies show that the DOB controller can achieve improved speed and power regulation compared to the baseline PID controller, and exhibit excellent robustness under different turbulent wind fields.

Robust Observer-Based Load Extenuation Control for Wind Turbines

2019 ◽  
Author(s):  
M. Hung Do ◽  
Dirk Söffker
Keyword(s):  
Wind Turbines ◽  
Large Scale ◽  
Linear Models ◽  
Simulation Software ◽  
Control Algorithms ◽  
Linear Quadratic ◽  
Robust Observer ◽  
Wind Turbine Control ◽  
Speed Regulation ◽  
The Stability

Abstract Wind energy is currently the fastest growing electricity source. To meet the output demand, wind turbines are becoming larger and more flexible leading to the problems of structural load especially in case of offshore turbines. Advanced control algorithms are developed to reduce the load, allowing to build larger turbines, and expand their lifetime. Observer-based control algorithms such as Linear-Quadratic-Gaussian LQG control which uses LQR to calculate the optimal observer and controller gains are commonly applied to wind turbines in literature. However the approach requires to calculate the observer and control gains separately. In addition, linear models used for parameter calculation may have errors with respect to the nonlinearities of wind turbines and induced to unmodeled dynamical properties. These modeling errors need to be considered to to guarantee the stability of the controlled system. Alternatively a robust design assuming bounds and limits of models have to be realized to guarantee stability while ignoring details of modeling. This paper proposes an optimal robust observer-based state feedback controller for large-scale wind turbines to realize multi objectives, including structural load mitigation and rotor speed regulation. The novel contribution is that the observer gain parameters, control gains, and integral action are optimized at the same time within H∞ mixed sensitivity framework to achieve desired performance with respect to power regulation, structural load mitigation, and also robustness for the wind turbine control system. The control performances have been verified by a high fidelity simulation software and are compared to those of a classical baseline controller.

Robust Model Reference Adaptive Control Design for Wind Turbine Speed Regulation Simulated by Using FAST

2018 ◽  
Vol 144 (2) ◽  
pp. 04018007 ◽  
Author(s):  
Xiao Wang ◽  
Wenzhong Gao ◽  
Tianqi Gao ◽  
Qiao Li ◽  
Jianhui Wang ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Wind Turbine ◽  
Control Design ◽  
Model Reference Adaptive Control ◽  
Model Reference ◽  
Speed Regulation ◽  
Robust Model ◽  
Turbine Speed ◽  
Model Reference Adaptive

Effects of Dynamic Model Errors in Task-Priority Operational Space Control

Robotica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Paolo Di Lillo ◽  
Gianluca Antonelli ◽  
Ciro Natale
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Null Space ◽  
Control Algorithms ◽  
Model Errors ◽  
Operational Space ◽  
Dynamic Level ◽  
Concurrent Tasks ◽  
Modeling Errors

SUMMARY Control algorithms of many Degrees-of-Freedom (DOFs) systems based on Inverse Kinematics (IK) or Inverse Dynamics (ID) approaches are two well-known topics of research in robotics. The large number of DOFs allows the design of many concurrent tasks arranged in priorities, that can be solved either at kinematic or dynamic level. This paper investigates the effects of modeling errors in operational space control algorithms with respect to uncertainties affecting knowledge of the dynamic parameters. The effects on the null-space projections and the sources of steady-state errors are investigated. Numerical simulations with on-purpose injected errors are used to validate the thoughts.

scholarly journals Dynamic Loads and Response of a Spar Buoy Wind Turbine with Pitch-Controlled Rotating Blades: An Experimental Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3598
Author(s):  
Sara Russo ◽  
Pasquale Contestabile ◽  
Andrea Bardazzi ◽  
Elisa Leone ◽  
Gregorio Iglesias ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Laboratory Data ◽  
Nonlinear Behavior ◽  
Offshore Wind ◽  
Small Scale ◽  
Wave Steepness ◽  
Design Factor

New large-scale laboratory data are presented on a physical model of a spar buoy wind turbine with angular motion of control surfaces implemented (pitch control). The peculiarity of this type of rotating blade represents an essential aspect when studying floating offshore wind structures. Experiments were designed specifically to compare different operational environmental conditions in terms of wave steepness and wind speed. Results discussed here were derived from an analysis of only a part of the whole dataset. Consistent with recent small-scale experiments, data clearly show that the waves contributed to most of the model motions and mooring loads. A significant nonlinear behavior for sway, roll and yaw has been detected, whereas an increase in the wave period makes the wind speed less influential for surge, heave and pitch. In general, as the steepness increases, the oscillations decrease. However, higher wind speed does not mean greater platform motions. Data also indicate a significant role of the blade rotation in the turbine thrust, nacelle dynamic forces and power in six degrees of freedom. Certain pairs of wind speed-wave steepness are particularly unfavorable, since the first harmonic of the rotor (coupled to the first wave harmonic) causes the thrust force to be larger than that in more energetic sea states. The experiments suggest that the inclusion of pitch-controlled, variable-speed blades in physical (and numerical) tests on such types of structures is crucial, highlighting the importance of pitch motion as an important design factor.

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