Adaptive Disturbance Tracking Control for Large Horizontal Axis Wind Turbines in Variable Speed Transition Operation

In a continuing effort to enhance the performance of small wind energy systems, one root airfoil and three primary airfoils were specifically designed for small horizontal axis wind turbines. These airfoils are intended primarily for 1–5 kW variable-speed wind turbines for both conventional (tapered/twisted) or pultruded blades. The four airfoils were wind-tunnel tested at Reynolds numbers between 100,000 and 500,000. Tests with simulated leading-edge roughness were also conducted. The results indicate that small variable-speed wind turbines should benefit from the use of the new airfoils which provide enhanced lift-to-drag ratio performance as compared with previously existing airfoils.

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Disturbance Tracking and Blade Load Control of Wind Turbines in Variable-Speed Operation

ASME 2003 Wind Energy Symposium ◽

10.1115/wind2003-1042 ◽

2003 ◽

Cited By ~ 10

Author(s):

Karl A. Stol

Keyword(s):

Wind Turbines ◽

Tracking Control ◽

Nonlinear Effects ◽

Load Control ◽

Variable Speed ◽

Composite State ◽

Energy Capture ◽

Simulation Results ◽

State Models ◽

Disturbance Tracking Control

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.

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An investigation of variable speed horizontal-axis wind turbines using direct model-reference adaptive control

10.2514/6.1999-28 ◽

1999 ◽

Cited By ~ 15

Author(s):

J. Freeman ◽

M. Balas

Keyword(s):

Adaptive Control ◽

Wind Turbines ◽

Model Reference Adaptive Control ◽

Horizontal Axis ◽

Variable Speed ◽

Model Reference ◽

Direct Model ◽

Horizontal Axis Wind Turbines ◽

Model Reference Adaptive

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Disturbance Tracking Control and Blade Load Mitigation for Variable-Speed Wind Turbines

Journal of Solar Energy Engineering ◽

10.1115/1.1628678 ◽

2003 ◽

Vol 125 (4) ◽

pp. 396-401 ◽

Cited By ~ 25

Author(s):

Karl A. Stol

Keyword(s):

State Space ◽

Fatigue Damage ◽

Wind Turbines ◽

Tracking Control ◽

Variable Speed ◽

Energy Capture ◽

State Models ◽

Linear State ◽

Disturbance Tracking Control ◽

Estimator Design

A composite linear 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; this led to the design of a complementary pitch controller. The goal of the independent blade pitch design was to minimize blade root fatigue loads. A SymDyn model of a two-bladed, 600-kW machine was used for the simulation studies. Results indicate a 24% reduction in blade fatigue damage using the proposed controllers, compared to a conventional torque-only design. However, energy capture was not improved as much as expected, partly due to nonlinearity effects degrading the performance of the state-space estimator design. Tower base fatigue damage was shown to decrease significantly using active pitch.

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