scholarly journals Predicting the Extreme Loads in Power Production of Large Wind Turbines Using an Improved PSO Algorithm

2019 ◽  
Vol 9 (3) ◽  
pp. 521 ◽  
Author(s):  
Caicai Liao ◽  
Kezhong Shi ◽  
XiaoLu Zhao
Keyword(s):  
Control System ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Bending Moment ◽  
Pso Algorithm ◽  
Power Production ◽  
Bending Moments ◽  
Rotor Speed ◽  
Blade Root ◽  
Extreme Loads

Predicting the extreme loads in power production for the preliminary-design of large-scale wind turbine blade is both important and time consuming. In this paper, a simplified method, called Particle Swarm Optimization-Extreme Load Prediction Model (PSO-ELPM), is developed to quickly assess the extreme loads. This method considers the extreme loads solution as an optimal problem. The rotor speed, wind speed, pitch angle, yaw angle, and azimuth angle are selected as design variables. The constraint conditions are obtained by considering the influence of the aeroelastic property and control system of the wind turbine. An improved PSO algorithm is applied. A 1.5 MW and a 2.0 MW wind turbine are chosen to validate the method. The results show that the extreme root load errors between PSO-ELPM and FOCUS are less than 10%, while PSO-ELPM needs much less computational cost than FOCUS. The distribution of flapwise bending moments are close to the results of FOCUS. By analyzing the loads, we find that the extreme flapwise bending moment of the blade root in chord coordinate (CMF_ROOT) is largely reduced because of the control system, with the extreme edgewise bending moment of the blade root in chord coordinate (CME_ROOT) almost unchanged. Furthermore, higher rotor speed and smaller pitch angle will generate larger extreme bending moments at the blade root.

Control Co-Design for Rotor Blades of Floating Offshore Wind Turbines

2020 ◽  
Author(s):  
Xianping Du ◽  
Laurent Burlion ◽  
Onur Bilgen
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Cone Angle ◽  
Bending Moment ◽  
Rotor Blades ◽  
Offshore Wind ◽  
Step Response ◽  
Offshore Wind Turbine ◽  
Blade Root ◽  
Floating Offshore Wind Turbines

Abstract This paper aims to demonstrate the application of control co-design methodology for the rotor blades of a floating offshore wind turbine. A 10 MW reference wind turbine model is utilized in the co-design framework. In this paper, the coupling effect between the system, defined by the pre-cone angle, and the controller, defined by pitch angle, is analyzed with a parametric study. The system parameters of the blade are identified by exciting the system with a step input, and by using the step response. The identified model is used to demonstrate the coupling effects of the structural parameters. The control co-design process is implemented to reduce the blade root bending moment by controlling the pitch angle as a function of the pre-cone angle. Utilizing the 10 MW reference model, the proposed control co-design method can reduce the blade root bending moment and attenuate transverse vibrations faster than the original design. Compared to a sequentially designed controller, the co-design demonstrated reduction of the blade root bending moment with similar attenuation time.

Individual Blade Pitch Control for Alleviation of Vibratory Loads on Floating Offshore Wind Turbines

2021 ◽  
Author(s):  
Luca Pustina ◽  
Claudio Pasquali ◽  
Jacopo Serafini ◽  
Claudio Lugni ◽  
Massimo Gennaretti
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Bending Moment ◽  
Offshore Wind ◽  
Synthesis Process ◽  
Control Synthesis ◽  
Offshore Wind Turbine ◽  
Floating Offshore Wind Turbine ◽  
Blade Root ◽  
Floating Offshore Wind Turbines

Abstract Among the renewable energy technologies, offshore wind energy is expected to provide a significant contribution for the achievement of the European Renewable Energy (RE) targets for the next future. In this framework, the increase of generated power combined with the alleviation of vibratory loads achieved by application of suitable advanced control systems can lead to a beneficial LCOE (Levelized Cost Of Energy) reduction. This paper defines a control strategy for increasing floating offshore wind turbine lifetime through the reduction of vibratory blade and hub loads. To this purpose a Proportional-Integral (PI) controller based on measured blade-root bending moment feedback provides the blade cyclic pitch to be actuated. The proportional and integral gain matrices are determined by an optimization procedure whose objective is the alleviation of the vibratory loads due to a wind distributed linearly on the rotor disc. This control synthesis process relies on a linear, state-space, reduced-order model of the floating offshore wind turbine derived from aero-hydroelastic simulations provided by the open-source tool OpenFAST. In addition to the validation of the proposed controller, the numerical investigation based on OpenFAST predictions examines also the corresponding control effort, influence on platform dynamics and expected blade lifetime extension. The outcomes show that, as a by-product of the alleviation of the vibratory out-of-plane bending moment at the blade root, significant reductions of both cumulative blade lifetime damage and sway and roll platform motion are achieved, as well. The maximum required control power is less than 1% of the generated power.

scholarly journals Development of Hardware-in-the-Loop-Simulation Testbed for Pitch Control System Performance Test

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2031
Author(s):  
Jongmin Cheon ◽  
Jinwook Kim ◽  
Joohoon Lee ◽  
Kichang Lee ◽  
Youngkiu Choi
Keyword(s):  
Control System ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Shear ◽  
Performance Test ◽  
Control Function ◽  
Hardware In The Loop ◽  
Rotor Speed ◽  
Test Bed ◽  
Pitch Control

This paper deals with the development of a wind turbine pitch control system and the construction of a Hardware-in-the-Loop-Simulation (HILS) testbed for the performance test of the pitch control system. When the wind speed exceeds the rated wind speed, the wind turbine pitch controller adjusts the blade pitch angles collectively to ensure that the rotor speed maintains the rated rotor speed. The pitch controller with the individual pitch control function can add individual pitch angles into the collective pitch angles to reduce the mechanical load applied to the blade periodically due to wind shear. Large wind turbines often experience mechanical loads caused by wind shear phenomena. To verify the performance of the pitch control system before applying it to an actual wind turbine, the pitch control system is tested on the HILS testbed, which acts like an actual wind turbine system. The testbed for evaluating the developed pitch control system consists of the pitch control system, a real-time unit for simulating the wind and the operations of the wind turbine, an operational computer with a human–machine interface, a load system for simulating the actual wind load applied to each blade, and a real pitch bearing. Through the several tests based on HILS test bed, how well the pitch controller performed the given roles for each area in the entire wind speed area from cut-in to cut-out wind speed can be shown.

Design, modeling and implementation of a novel pitch angle control system for wind turbine

2015 ◽  
Vol 81 ◽  
pp. 599-608 ◽  
Author(s):  
Xiu-xing Yin ◽  
Yong-gang Lin ◽  
Wei Li ◽  
Ya-jing Gu ◽  
Xiao-jun Wang ◽  
...  
Keyword(s):  
Control System ◽  
Wind Turbine ◽  
Pitch Angle

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.

Effect of Shut-Down Procedures on the Dynamic Responses of a Spar-Type Floating Wind Turbine

2013 ◽  
Author(s):  
Zhiyu Jiang ◽  
Torgeir Moan ◽  
Zhen Gao ◽  
Madjid Karimirad
Keyword(s):  
Wind Turbine ◽  
Effective Means ◽  
Bending Moment ◽  
Dynamic Responses ◽  
Structural Safety ◽  
Wave Loads ◽  
Main Shaft ◽  
Rotor Speed ◽  
Design Standards ◽  
Floating Wind Turbine

The design standards (IEC, DNV and GL) define a minimum set of combinations of external conditions and design situations as load cases. Like other design load conditions, the design situations relating to fault and shut-down events shall be addressed. Emergency shut down occurs in the presence of severe faults to prevent turbine damage. For pitch-regulated turbines, blade pitching to feather provides an effective means of aerodynamic braking. The blades are pitched to feather at the maximum pitch rate. This action exerts huge loading on the turbine and may challenge the structural safety. In this paper a 5-MW spar-type wind turbine is used as a case study. By using the HAWC2 code, the turbine pitch actuator fault and shut-down scenarios are simulated through external Dynamic Link Libraries. The shut-down scenarios are: normal shut down with blade pitching, emergency shut down with blade pitching, and emergency shut down with blade pitching and mechanical brake. Due to the occurrence of fault, the pitch angle of one blade is fixed from a specific occurrence time. The supervisory controller reacts by pitching the remaining two blades to the maximum pitch set. The maximum yaw motion value is observed after the first revolution of the rotor during which the tower-top torsion experiences a change of direction. Negative platform pitch motion as well as tower-bottom bending moment are induced due to the pitching activity of the two blades. The response extremes of the main shaft bending moment and the yaw motion exhibit clear variation with the blade azimuth when emergency shut down is initiated. The tower-bottom bending moment and nacelle acceleration are relatively more affected by the wave loads. For a given blade azimuth, larger response variation is observed under harsher environmental conditions. Under the fault scenario, the effects of different shut-down procedures on the response extremes are investigated. It is found that the response extremes are affected significantly by the rotor speed. Among the three procedures, normal shut down, which is associated with the slowest decaying aerodynamic excitations and the highest rotor speed, usually leads to the largest response extremes near the rated wind speed. The employment of mechanical brake reduces rotor speed, motion responses and structural responses effectively. During shut down, the responses of yaw motion, nacelle fore-aft acceleration, main shaft bending moment, and tower-bottom side-to-side moment may be of concern for the floating wind turbine studied.

Extreme load estimation of the wind turbine tower during power production

2019 ◽  
pp. 0309524X1987276
Author(s):  
Atsushi Yamaguchi ◽  
Prasanti Widyasih Sarli ◽  
Takeshi Ishihara
Keyword(s):  
Bending Moment ◽  
Power Production ◽  
Data Sets ◽  
Bending Moments ◽  
Recurrence Period ◽  
Wind Turbine Tower ◽  
Extreme Load ◽  
Predicted Values ◽  
New Criterion ◽  
Good Agreement

Wind turbines have to be designed against extreme load during power production with the recurrence period of 50 years. This extreme load is usually calculated through statistical extrapolation. However, large uncertainties exist in the estimation of the extreme load. This study aims to reduce these uncertainties in the statistical extrapolation by using systematic simulations. First, a new criterion is proposed for the data sets to be used for the statistical extrapolation and the resulting uncertainty satisfies the requirement in the standard for prediction of wind load. Then, a new extrapolation factor for load extrapolation is proposed and the predicted maximum tower bending moments at all the heights show favorable agreement with measurement. Finally, empirical formulae are proposed to estimate the expected value of the maximum tower bending moment and the predicted values show good agreement with the numerical simulations.

scholarly journals Optimal Power Reserve of a Wind Turbine System Participating in Primary Frequency Control

2018 ◽  
Vol 8 (11) ◽  
pp. 2022 ◽  
Author(s):  
Abdullah Bubshait ◽  
Marcelo G. Simões
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Control Method ◽  
Frequency Control ◽  
Synchronous Generator ◽  
Rotor Speed ◽  
Wind Turbine System ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
And Control

Participation of a wind turbine (WT) in primary frequency control (PFC) requires reserving some active power. The reserved power can be used to support the grid frequency. To maintain the required amount of reserve power, the WT is de-loaded to operate under its maximum power. The objective of this article is to design a control method for a WT system to maintain the reserved power of the WT, by controlling both pitch angle and rotor speed simultaneously in order to optimize the operation of the WT system. The pitch angle is obtained such that the stator current of the permanent magnet synchronous generator (PMSG) is reduced. Therefore, the resistive losses in the machine and the conduction losses of the converter are minimized. To avoid an excessive number of pitch motor operations, the wind forecast is implemented in order to predict consistent pitch angle valid for longer timeframe. Then, the selected pitch angle and the known curtailed power are used to find the optimal rotor speed by applying a nonlinear equation solver. To validate the proposed de-loading approach and control method, a detailed WT system is modeled in Matlab/Simulink (The Mathworks, Natick, MA, USA, 2017). Then, the proposed control scheme is validated using hardware-in-the-loop and real time simulation built in Opal-RT (10.4.14, Opal-RT Inc., Montreal, PQ, Canada).

Experimental verification of predicted capability of a wind turbine drivetrain test bench to replicate dynamic loads onto multi-megawatt nacelles

2022 ◽  
pp. 0309524X2110653
Author(s):  
Philippe Giguère ◽  
John R Wagner
Keyword(s):  
Wind Turbine ◽  
Evaluation Method ◽  
Test Bench ◽  
Tracking Error ◽  
Bending Moment ◽  
Dynamic Loads ◽  
Bending Moments ◽  
Ramp Rate ◽  
Early Screening ◽  
Test Profiles

A total of 27 test profiles from the IEC 61400-1 design load cases were tested using a 7.5-MW wind turbine drivetrain test bench and two multi-megawatt wind turbine drivetrains. Each test profile consisted of simultaneous vertical, lateral, and longitudinal forces, yawing and nodding bending moment, and rotational speed. These test-bench inputs were compared with the forces, bending moments, and speed that were applied to the wind turbine drivetrains to quantify the test-bench tracking error. This tracking error was quantified for a range of ramp-rate limits of the yawing and nodding bending moments. The experimental results were compared with predictions from an evaluation method for the capability of wind turbine drivetrain test benches to replicate dynamic loads. The method’s predictive capability was found to be sufficient for the goal of early screening and its formulation is applicable to any wind turbine drivetrain test bench and drivetrain design.

Frequency Versus Time Domain Fatigue Analysis of a Semisubmersible Wind Turbine Tower

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Marit I. Kvittem ◽  
Torgeir Moan
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Time Domain ◽  
Low Frequency ◽  
Bending Moment ◽  
Good Representation ◽  
Bending Moments ◽  
Wave Loads ◽  
Flexible Mode ◽  
Standard Deviations

The current paper deals with a study of a semisubmersible wind turbine (WT), where short-term tower base bending moments and tower fatigue damage were estimated by a frequency domain (FD) method. Both a rigid structure assumption and a generalized degree-of-freedom (DOF) model for including the first flexible mode of the turbine tower were investigated. First, response to wind and wave loads was considered separately, then superposition was used to find the response to combined wind and wave loading. The bending moments and fatigue damage obtained by these methods were compared to results from a fully coupled, nonlinear time domain (TD) analysis. In this study a three column, catenary moored semisubmersible with the NREL 5 MW turbine mounted on one of the columns was modeled. The model was inspired by the WindFloat concept. The TD simulation tool used was Simo-Riflex-AeroDyn from Marintek and CeSOS. The FD method gave a good representation of the tower base bending moment histories for wave-only analyses, for the moderate sea states considered in these analyses. With the assumption that the structure is completely rigid, bending moments were underestimated, but including excitation of the elastic tower and blades, improved the results. The wind-induced low-frequency bending moments were not captured very well, which presumably comes from a combination of nonlinear effects being lost in the linearization of the thrust force and that the aerodynamic damping model was derived for a fixed turbine. Nevertheless, standard deviations of the bending moments were still reasonable. The FD model captured the combined wind and wave analyses quite well when a generalized coordinates model for wind excitation of the first bending mode of the turbine was included. The FD fatigue damage predictions were underestimated by 0–60%, corresponding to discrepancies in standard deviations of stress in the order of 0–20%.

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