Prediction models for wind speed at turbine locations in a wind farm

Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads and, potentially, instability of the controlled system. In this paper, the wave excitation is investigated, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring system and tower side-side motion, including gyroscopic effects. The models support a model-based design that includes estimators for wind speed and wave frequency. The design is applied to a number of examples representing different wind and wave conditions and successfully demonstrates a reduction in the structural oscillations, while improving power performance.

show abstract

“…In this study, an extended Kalman filter (EKF) is used to estimate the wind speed, as suggested in [20].…”

Section: Wind Speed Estimatormentioning

confidence: 99%

Damping Wind and Wave Loads on a Floating Wind Turbine

2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is however well described in [3]. In brief, v t The DI inflow part (19e), (19j) and (19k) is new while the rest of the aerodynamics (19l)-(19n) is standard except that the fictive wind v f is used for rotor torque and thrust.…”

Section: Extended Kalman Filtermentioning

confidence: 99%

“…The prediction error assessment is made for both simple simulation model data and for full scale experimental data. Notice that the EKF has a significant value on its own as it also estimates the effective wind speed (EWS) which is used for single turbine control [3]- [6].…”

Section: Introductionmentioning

confidence: 99%

Simple model for describing and estimating wind turbine dynamic inflow

Knudsen

Bak

2013

2013 American Control Conference

Self Cite

View full text Add to dashboard Cite

Abstract-Wind turbines operate with sudden change in pitch angle, rotor or wind speed. In such cases the wake behind the turbine, achieve steady state conditions only after a certain delay. This phenomenon is commonly called dynamic inflow.There are many models for dynamic inflow. The most accurate use a method that can be characterised as the blade element momentum method plus a dynamic equation for the induction factor. This method then needs calculations along the blade for a number of sections including numerical solution of equations. This is numerical demanding. The simplest models amounts to placing a lead-lag filter after rotor torque and thrust calculated from static tables of the power and thrust coefficients. The filter constants will then vary with average wind speed. The filtered versions of torque and thrust are then an approximate modelling of the dynamic inflow. The dynamic inflow model suggested here places itself in between the most complex and the most simple both in accuracy, numerical demands and physical appeal. The suggested models behavior is demonstrated by simulation and the usefulness for extended Kalman filtering is assessed both via simulated data and real full scale turbine data.

show abstract

“…The wind speed is modeled as v = v m + v t where v t is the turbulent wind and v m is a slowly varying mean wind speed as described in [15]. These are modeled aṡ…”

Section: B Stochastic Wind and Wave Modelsmentioning

confidence: 99%

“…Based on the available measurements, an EKF is implemented to estimate the unmeasured states as described in [15]. The deterministic model in Eq.…”

Section: E State Estimationmentioning

confidence: 99%

Wave disturbance reduction of a floating wind turbine using a reference model-based predictive control

Christiansen

Tabatabaeipour

Bak

et al. 2013

2013 American Control Conference

View full text Add to dashboard Cite

Abstract-Floating wind turbines are considered as a new and promising solution for reaching higher wind resources beyond the water depth restriction of monopile wind turbines. But on a floating structure, the wave-induced loads significantly increase the oscillations of the structure. Furthermore, using a controller designed for an onshore wind turbine yields instability in the fore-aft rotation. In this paper, we propose a general framework, where a reference model models the desired closed-loop behavior of the system. Model predictive control combined with a state estimator finds the optimal rotor blade pitch such that the state trajectories of the controlled system tracks the reference trajectories. The framework is demonstrated with a reference model of the desired closedloop system undisturbed by the incident waves. This allows the wave-induced motion of the platform to be damped significantly compared to a baseline floating wind turbine controller at the cost of more pitch action.

show abstract

Prediction models for wind speed at turbine locations in a wind farm

Cited by 104 publications

References 10 publications

Damping Wind and Wave Loads on a Floating Wind Turbine

Damping Wind and Wave Loads on a Floating Wind Turbine

Simple model for describing and estimating wind turbine dynamic inflow

Wave disturbance reduction of a floating wind turbine using a reference model-based predictive control

Contact Info

Product

Resources

About