scholarly journals Implementation and Validation of an Advanced Wind Energy Controller in Aero-Servo-Elastic Simulations Using the Lifting Line Free Vortex Wake Model

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 783 ◽  
Author(s):  
Sebastian Perez-Becker ◽  
David Marten ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Open Source ◽  
Control Strategy ◽  
Vortex Wake ◽  
Load Reduction ◽  
Free Vortex ◽  
Pitch Control ◽  
The Individual ◽  
Individual Pitch Control ◽  
Lifting Line

Accurate and reproducible aeroelastic load calculations are indispensable for designing modern multi-MW wind turbines. They are also essential for assessing the load reduction capabilities of advanced wind turbine control strategies. In this paper, we contribute to this topic by introducing the TUB Controller, an advanced open-source wind turbine controller capable of performing full load calculations. It is compatible with the aeroelastic software QBlade, which features a lifting line free vortex wake aerodynamic model. The paper describes in detail the controller and includes a validation study against an established open-source controller from the literature. Both controllers show comparable performance with our chosen metrics. Furthermore, we analyze the advanced load reduction capabilities of the individual pitch control strategy included in the TUB Controller. Turbulent wind simulations with the DTU 10 MW Reference Wind Turbine featuring the individual pitch control strategy show a decrease in the out-of-plane and torsional blade root bending moment fatigue loads of 14% and 9.4% respectively compared to a baseline controller.

Coupling of an Unsteady Lifting Line Free Vortex Wake Code to the Aeroelastic HAWT Simulation Suite FAST

2016 ◽  
Author(s):  
Joseph Saverin ◽  
David Marten ◽  
George Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Open Source ◽  
Operating Conditions ◽  
Analysis Tool ◽  
Vortex Wake ◽  
Free Vortex ◽  
Blade Loading ◽  
Simplifying Assumptions ◽  
Aeroelastic Simulations ◽  
Lifting Line

A coupling of the Lifting Line Free Vortex Wake (LLFVW) model of the open source wind turbine software QBlade and the wind turbine structural analysis tool FAST has been achieved. FAST has been modified and compiled as a dynamic library, taking rotor blade loading from the LLFVW model as input. Most current wind turbine aeroelastic simulations make use of the Blade Element Momentum (BEM) model, based upon a number of simplifying assumptions which are often violated in unsteady situations. The purpose of the implemented model is to improve accuracy under unsteady conditions. The coupling has been thoroughly validated against the NREL 5MW reference turbine. The turbine is compared under both steady conditions and three unsteady operating conditions to the BEM code AeroDyn. The turbine has been simulated operating at a constant RPM and with a variable-speed, variable blade-pitch-to-feather controller. Under steady conditions the agreement between the LLFVW and AeroDyn is demonstrated to be very good. The LLFVW produces different predictions for rotor power, blade deflection and blade loading during transient conditions. A number of important observations have been made which illustrate the necessity of a higher fidelity aerodynamic model. The validation and results are considered as a step towards the implementation of an open-source, high fidelity aeroelastic tool for wind turbines.

The Study of Individual Pitch Control on Reducing The Load Fluctuation of Tower Shadow

2011 ◽  
Vol 347-353 ◽  
pp. 2260-2267
Author(s):  
Wei Li ◽  
Hong Li Sun ◽  
Zuo Xia Xing ◽  
Lei Chen
Keyword(s):  
Wind Turbine ◽  
Linear Time ◽  
Pitch Control ◽  
Linear Time Invariant ◽  
Load Fluctuation ◽  
Pitch System ◽  
The Individual ◽  
Time Invariant ◽  
Individual Pitch Control ◽  
Tower Shadow

Load fluctuation of wind turbine under tower shadow was researched，introducing individual pitch control. First，establish the linear time-varying model of the rotor，make it into the linear time invariant model through Coleman transformation. Then，based on this model，achieving the design of individual pitch system with PID controller. Comparing the loads of wind turbine under tower shadow between individual pitch control and collective pitch control and analysing the fatigue damage of wind turbine through rainflow cycle counting.The result shows that load fluctuation of wind turbine using the individual pitch control under tower shadow has better effect and reduces the effect of tower shadow，extend the working life of wind turbine.

Investigations on the Fatigue Load Reduction Potential of Advanced Control Strategies for Multi-MW Wind Turbines Using a Free Vortex Wake Model

2018 ◽  
Author(s):  
Sebastian Perez-Becker ◽  
Joseph Saverin ◽  
David Marten ◽  
Jörg Alber ◽  
George Pechlivanoglou ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Reduction Potential ◽  
Fatigue Loading ◽  
Vortex Wake ◽  
Load Reduction ◽  
Fatigue Load ◽  
Aerodynamic Forces ◽  
Actuation Frequency ◽  
Free Vortex ◽  
Wind Speeds

This paper presents the results of a fatigue load evaluation from aeroelastic simulations of a multi-megawatt wind turbine. Both the Blade Element Momentum (BEM) and the Lifting Line Free Vortex Wake (LLFVW) methods were used to compute the aerodynamic forces. The loads in selected turbine components, calculated from NREL’s FAST v8 using the aerodynamic solver AeroDyn, are compared to the loads obtained using the LLFVW aerodynamics formulation in QBlade. The DTU 10 MW Reference Wind Turbine is simulated in power production load cases at several wind speeds under idealized conditions. The aerodynamic forces and turbine loads are evaluated in detail, showing very good agreement between both codes. Additionally, the turbine is simulated under realistic conditions according to the current design standards. Fatigue loads derived from load calculations using both codes are compared when the turbine is controlled with a basic pitch and torque controller. It is found that the simulations performed with the BEM method generally predict higher fatigue loading in the turbine components. A higher pitch activity is also predicted with the BEM simulations. The differences are larger for wind speeds around rated wind speed. Furthermore, the fatigue reduction potential of the individual pitch control (IPC) strategy is examined and compared when using the two different codes. The IPC strategy shows a higher load reduction of the out-of-plane blade root bending moments when simulated with the LLFVW method. This is accompanied with higher pitch activity at the actuation frequency of the IPC strategy.

Individual Pitch Control for Wind Turbine Load Reduction Enhanced With Inter-Turbine Wake Modelling

2011 ◽  
Author(s):  
Zhongzhou Yang ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
Wind Profile ◽  
State Space Models ◽  
Load Reduction ◽  
Pitch Control ◽  
Wake Interaction ◽  
Wake Model ◽  
Individual Pitch Control ◽  
Turbine Wake

Individual pitch control (IPC) for wind turbine load reduction in Region 3 operation is improved when wake interaction is considered. The Larsen wake model is applied for composing the rotor wind profile for downstream turbines under wake interaction. The wind profile of the turbine wake was generated by modifying the NREL’s TurbSim codes. The state-space models of wind turbine were obtained via linearization of wind turbine model available in the NREL’s aeroelastic design code FAST. In particular, in order to obtain more accurate state-space models, equivalent circular wind profile was generated so as to better determine the local pitch reference. Based on such models, IPC controllers were designed following the disturbance accommodating control (DAC) and periodic control framework. The simulation results showed that the turbine loads can be further reduced using the switching control scheme based on wake modeling, as compared with the generic DAC without wake consideration.

scholarly journals Is the Blade Element Momentum Theory overestimating Wind Turbine Loads? – A Comparison with a Lifting Line Free Vortex Wake Method

2019 ◽  
Author(s):  
Sebastian Perez-Becker ◽  
Francesco Papi ◽  
Joseph Saverin ◽  
David Marten ◽  
Alessandro Bianchini ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vortex Wake ◽  
Bending Moments ◽  
Free Vortex ◽  
Aerodynamic Loads ◽  
Blade Root ◽  
Out Of Plane ◽  
Design Loads ◽  
Lifting Line ◽  
Blade Element

Abstract. Load calculations play a key role in determining the design loads of different wind turbine components. State of the art in the industry is to use the Blade Element Momentum (BEM) theory to calculate the aerodynamic loads. Due to their simplifying assumptions of the rotor aerodynamics, BEM methods have to rely on several engineering correction models to capture the aerodynamic phenomena present in Design Load Cases (DLCs) with turbulent wind. Because of this, BEM methods can overestimate aerodynamic loads under challenging conditions when compared to higher-order aerodynamic methods - such as the Lifting Line Free Vortex Wake (LLFVW) method – leading to unnecessarily high design loads and component costs. In this paper, we give a quantitative answer to the question of BEM load overestimation by comparing the results of aeroelastic load calculations done with the BEM-based OpenFAST code and the QBlade code which uses a LLFVW method. We compare extreme and fatigue load predictions from both codes using 66 ten-minute load simulations of the DTU 10 MW Reference Wind Turbine according to the IEC 61400-1 power production DLC group. Results from both codes show differences in fatigue and extreme load estimations for practically all considered sensors of the turbine. LLFVW simulations predict 4 % and 14 % lower lifetime Damage Equivalent Loads (DELs) for the out-of-plane blade root and the tower base fore-aft bending moments, when compared to BEM simulations. The results also show that lifetime DELs for the yaw bearing tilt- and yaw moments are 2 % and 4 % higher when calculated with the LLFVW code. An ultimate state analysis shows that extreme loads of the blade root out-of-plane and the tower base fore-aft bending moments predicted by the LLFVW simulations are 3 % and 8 % lower than the moments predicted by BEM simulations, respectively. Further analysis reveals that there are two main contributors to these load differences. The first is the different treatment in both codes of the effect that sheared inflow has on the local blade aerodynamics and second is the wake memory effect model which was not included in the BEM simulations.

Research on Joint Power and Loads Control for Large Scale Directly Driven Wind Turbines

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
JuChuan Dai ◽  
Deshun Liu ◽  
Yanping Hu ◽  
Xiangbing Shen
Keyword(s):  
Wind Turbines ◽  
Control Strategy ◽  
Pitch Angle ◽  
Large Scale ◽  
Synchronous Generator ◽  
Joint Power ◽  
Pitch Control ◽  
The Difference ◽  
The Individual ◽  
Individual Pitch Control

Emphasis of this article is on the dynamic characteristics analysis of individual pitch control for MW scale directly driven wind turbines with permanent magnet synchronous generator (PMSG). The pitch control objectives were analyzed and the objective expressions were deduced, including power expression, loads expression, and vibration expressions of blade and tower. Then, both the collective pitch control aiming at power control and the individual pitch control strategy aiming at joint power and loads control were analyzed, too. The blade root bending moments and the actual capture power of wind rotor were employed to be the control variables. The power was calculated based on the conventional measured parameters of wind turbines. In order to reflect the difference between the pitch angle command value and the actual value, the pitch actuator dynamic model was used. The research results show that both the collective pitch control strategy and the proposed individual pitch control strategy can effectively control the power injected into grid; moreover, the individual pitch control can reduce fatigue loads; while in the process of individual pitch control, the actual variation of blade pitch angle is closely related to not only the inflow speed but also the blade azimuth angle; individual pitch control strategy can reduce the variation amplitude of flapwise moments, but has little influence on the edgewise moments.

scholarly journals Wind Turbine Collective and Individual Pitch Control Using Quantitative Feedback Theory

2017 ◽  
Author(s):  
Laura H. Wheeler ◽  
Mario Garcia-Sanz
Keyword(s):  
Wind Turbine ◽  
Quantitative Feedback Theory ◽  
Harmonic Frequency ◽  
Mechanical Loads ◽  
Pitch Control ◽  
Wind Turbine Control ◽  
Mechanical Fatigue ◽  
Horizontal Axis Wind Turbines ◽  
The Individual ◽  
Individual Pitch Control

Individual pitch control is an innovative technique in wind turbine control. It has the potential of reducing the asymmetric mechanical loads on the blades in large multi-megawatt turbines. As the mechanical fatigue is reduced, the lifetime of the turbine can be significantly extended. This work develops an individual pitch control for the National Renewable Energy Laboratory’s (NREL) 5 MW reference wind turbine. The individual pitch controller works along with a collective pitch controller, designed using Quantitative Feedback Theory (QFT) robust control. Simulations of the complete individual and collective pitch control system are conducted with the NREL’s computer-aided engineering tool for horizontal axis wind turbines (FAST). They show that the addition of the individual pitch controller significantly reduces the loads on the tilt and yaw directions in the nacelle and tower of the turbine at 1P and 3P frequencies, and on the blades at the 2P harmonic frequency.

Sign in / Sign up

Export Citation Format

Share Document