Pitch Control for Wind Turbine in Yawed Inflow Condition

2014 ◽  
Author(s):  
Irving Paul Girsang ◽  
Jaspreet Singh Dhupia
Keyword(s):  
Wind Turbine ◽  
Bending Moments ◽  
Misalignment Angle ◽  
Operating Condition ◽  
Pitch Control ◽  
Angle Correction ◽  
Inflow Condition ◽  
Simulation Results ◽  
Blade Loads ◽  
Inflow Conditions

A wind turbine can experience yawed inflow with large yaw misalignment angle during faulty cases, such as faults in the yaw controller/drives, or during extreme atmospheric cases, such as thunderstorm downbursts. In such cases, it is risky for the turbine to continue operation because it is being exposed to large loads. Instead, it is recommended for the turbine to be transited to parking conditions. Currently, most turbine pitch controllers are designed without considering the yaw misalignment angle, correction of which is normally assigned to the yaw controller. This paper investigates the contribution of both a baseline and a proposed collective pitch controllers under yawed inflow conditions. The baseline controller tries to maintain the rated operating condition at an expense of large blade loads. On the contrary, simulation results show that the proposed controller slows down the turbine under the presence of yawed inflow, which helps to park the turbine and reduces the average blade root bending moments.

scholarly journals Vibration Reduction Strategy for Offshore Wind Turbines

2020 ◽  
Vol 10 (17) ◽  
pp. 6091
Author(s):  
Haoming Liu ◽  
Suxiang Yang ◽  
Wei Tian ◽  
Min Zhao ◽  
Xiaoling Yuan ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Reference Signal ◽  
Offshore Wind ◽  
Wave Load ◽  
Offshore Wind Turbines ◽  
Pitch Control ◽  
Simulation Results ◽  
Aerodynamic Torque

The operational environment of offshore wind turbines is much more complex than that of onshore wind turbines. Facing the persistent wind and wave forces, offshore wind turbines are prone to vibration problems, which are not conducive to their long-term operation. Under this background, first, how the wave affects the vibration characteristics of offshore wind turbines is analyzed. Based on the existing wave and wave load models, we analytically show that there exist fluctuating components related to the hydrodynamic frequency in the aerodynamic load and aerodynamic torque of offshore wind turbines. Simulation results based on a GH Bladed platform further validates the analysis. Second, in order to reduce the joint impacts of the wave, wind shear and tower shadow on the wind turbine, a variable pitch control method is proposed. The integrated tower top vibration acceleration signal is superimposed on the collective pitch reference signal, then the triple frequency (3P) fluctuating component of the wind turbine output power and the azimuth angle of each blade are converted into the pitch angle adjustment signal of each blade, which is superimposed on the collective pitch signal for individual pitch control. The simulation results show that the proposed pitch control strategy can effectively smooth the fluctuation of blade root flap-wise load caused by wind and wave, and significantly reduce the fluctuation of aerodynamic torque and output power of offshore wind turbines.

scholarly journals A Comparison of Predicted Wind Turbine Blade Loads to Test Measurements

1988 ◽  
Vol 110 (3) ◽  
pp. 180-186 ◽  
Author(s):  
A. D. Wright ◽  
R. W. Thresher
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Scale Model ◽  
Bending Moments ◽  
Energy Research ◽  
Wind Speeds ◽  
Loads Analysis ◽  
Wind Tunnel Data ◽  
Blade Loads

The accurate prediction of wind turbine blade loads and response is important in predicting the fatigue life of wind machines. At the SERI Wind Energy Research Center, a rotor code called FLAP (Force and Loads Analysis Program) is currently being validated by comparing predicted results to machine measurements. The FLAP code has been modified to allow the teetering degree of freedom. This paper describes these modifications and comparisons of predicted blade bending moments to test measurements. Wind tunnel data for a 1/20th scale model will be used to compare FLAP predictions for the cyclic flap-bending moments at the 33 percent spanwise station for three different wind speeds. The comparisons will be made for both rigid and teetering hubs. Currently, the FLAP code accounts for deterministic excitations such as wind shear, tower shadow, gravity, and prescribed yawing motions. Conclusions will be made regarding the code’s accuracy in predicting the cyclic bending moments.

Research on Loads Control of Wind Turbine Based on Disturbance Accommodating Control

2012 ◽  
Vol 522 ◽  
pp. 838-841
Author(s):  
Guo Yu Hu ◽  
Wen Lei Sun ◽  
Ji Zhe Hai ◽  
Yan Xu
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
High Speed ◽  
Control Design ◽  
Maximum Power ◽  
Pi Control ◽  
Low Speed ◽  
Pitch Control ◽  
Disturbance Accommodating Control ◽  
Simulation Results

This paper uses modern control based on DAC control to numerically simulate a 1.5MW wind turbine. Through linearized modeling of 1.5MW wind turbine, this paper illustrates state-space control design and simulation for a 1.5MW wind turbine. This paper emphasizes on the use of DAC control to alleviate loads when the turbine is operating at maximum power. Loads diagrams of 1.5MW wind turbine including generator, low-speed shaft and high-speed shaft are obtained. The simulation results show that the collective pitch control based on DAC has certain effects on load alleviation compared to PI control.

scholarly journals Wind inflow observation from load harmonics

2017 ◽  
Vol 2 (2) ◽  
pp. 615-640 ◽  
Author(s):  
Marta Bertelè ◽  
Carlo L. Bottasso ◽  
Stefano Cacciola ◽  
Fabiano Daher Adegas ◽  
Sara Delport
Keyword(s):  
Numerical Simulations ◽  
Wind Turbine ◽  
Wind Field ◽  
Wind Farm ◽  
State Observer ◽  
High Fidelity ◽  
Bending Moments ◽  
Out Of Plane ◽  
Wind Characteristics ◽  
Blade Loads

Abstract. The wind field leaves its fingerprint on the rotor response. This fact can be exploited by using the rotor as a sensor: by looking at the rotor response, in the present case in terms of blade loads, one may infer the wind characteristics. This paper describes a wind state observer that estimates four wind parameters, namely the vertical and horizontal shears and the yaw and upflow misalignment angles, from out-of-plane and in-plane blade bending moments. The resulting observer provides on-rotor wind inflow characteristics that can be exploited for wind turbine and wind farm control. The proposed formulation is evaluated through extensive numerical simulations in turbulent and nonturbulent wind conditions using a high-fidelity aeroservoelastic model of a multi-MW wind turbine.

Individual Pitch Control of Horizontal Axis Wind Turbines

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Fredrik Sandquist ◽  
Geir Moe ◽  
Olimpo Anaya-Lara
Keyword(s):  
Wind Power ◽  
Wind Turbines ◽  
Rotor Speed ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Pitch Control ◽  
Horizontal Axis Wind Turbines ◽  
Simulation Results ◽  
Individual Pitch Control ◽  
Blade Loads

An individual pitch controller (IPC) based on the multivariable Linear Quadratic Gaussian (LQG) concept is presented to reduce loads in megawatt-size wind turbines. Most turbines currently installed use collective pitch control to pitch the blades in order to limit the excess of wind power and to regulate the rotor speed above rated conditions. However, research has shown that IPC control is much more effective to reduce blade loads. Both collective and individual pitch control are implemented for the NREL 5 MW reference turbine. Simulation results are used to illustrate the advantage of the IPC approach, and its ability to reduce much of the flap-wise blade motion is demonstrated.

scholarly journals Development of a Curled Wake of a Yawed Wind Turbine under Turbulent and Sheared Inflow

2021 ◽  
Author(s):  
Paul Hulsman ◽  
Martin Wosnik ◽  
Vlaho Petrović ◽  
Michael Hölling ◽  
Martin Kühn
Keyword(s):  
Energy Dissipation ◽  
Wind Turbine ◽  
Dissipation Rate ◽  
Vortex Pair ◽  
Turbine Rotor ◽  
Energy Dissipation Rate ◽  
Hot Wire ◽  
Inflow Condition ◽  
Inflow Turbulence ◽  
Inflow Conditions

Abstract. A potential technique to reduce the negative wake impact is to redirect it away from a downstream turbine by yawing the upstream turbine. The present research investigated the wake behaviour for three yaw angles [−30°, 0°, 30°] at different inflow turbulence levels and shear profiles under controlled conditions. Experiments were conducted using a model wind turbine with 0.6 m diameter (D) in a wind tunnel. A short-range dual-Doppler Lidar WindScanner facilitated mapping the wake with a high spatial and temporal resolution in vertical, cross-stream planes at different downstream locations and in a horizontal plane at hub height. This versatile equipment enabled the fast measurements at multiple locations in comparison to the well known hot-wire measurements. The flow structures and the energy dissipation rate of the wake were measured from 1D up to 10D, and for one inflow case up to 16D, downstream of the turbine rotor. A strong dependency of the wake characteristics on both the yaw angle and the inflow conditions was observed. In addition, the curled wake that develops under yaw misalignment due to the counter-rotating vortex pair was more pronounced with a boundary layer (sheared) inflow condition than for uniform inflow with different turbulence levels. Furthermore, the lidar velocity data and the energy dissipation rate compared favourably with hot-wire data from previous experiments with a similar inflow condition and wind turbine model in the same facility, lending credibility to the measurement technique and methodology used here. The measurement campaign provided a deeper understanding of the development of the wake at different inflow conditions, which will advance the process to improve existing wake models.

scholarly journals Wind inflow observation from load harmonics

2017 ◽  
Author(s):  
Marta Bertelè ◽  
Carlo L. Bottasso ◽  
Stefano Cacciola ◽  
Fabiano Daher Adegas ◽  
Sara Delport
Keyword(s):  
Numerical Simulations ◽  
Wind Turbine ◽  
Wind Field ◽  
Wind Farm ◽  
High Fidelity ◽  
Bending Moments ◽  
Turbulent Wind ◽  
Out Of Plane ◽  
Wind Characteristics ◽  
Blade Loads

Abstract. The wind field leaves its fingerprint on the rotor response. This fact can be exploited to use the rotor as a sensor: by looking at the rotor response, in the present case in terms of blade loads, one may infer the wind characteristics. This paper describes a wind state observer that estimates four wind parameters, namely the vertical and horizontal shears and the yaw and upflow misalignment angles, from out-of-plane and in-plane blade bending moments. The resulting observer provides on-rotor wind inflow characteristics that can be exploited for wind turbine and wind farm control. The proposed formulation is evaluated by extensive numerical simulations in turbulent and non-turbulent wind conditions using a high-fidelity aeroservoelastic model of a multi-MW wind turbine.

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