Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of tw...Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.展开更多
This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the...This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the proposed approach models the influence of the air density on the power production while employing the theoretical power curve. Consequently, the proposed approach provides a precise estimation of AEP, which can serve as a foundation of the optimum turbinesite matching design at different-altitude sites.展开更多
Due to varying characteristics of the wind condition, the performance of the wind turbines can be optimized by adapting the parameters of the control system. In this letter, an adaptive technique is proposed for the n...Due to varying characteristics of the wind condition, the performance of the wind turbines can be optimized by adapting the parameters of the control system. In this letter, an adaptive technique is proposed for the novel model predictive control(MPC) for the yaw system of the wind turbines. The control horizon is adapted to the one with the best predictive performance among multiple control horizons. The adaptive MPC is demonstrated by simulations using real wind data, and its performance is compared with the baseline MPC at fixed control horizon. Results show that the adaptive MPC provides better comprehensive performance than the baseline ones at different preview time of wind directions. Therefore, the proposed adaptive technique is potentially useful for the wind turbines in the future.展开更多
In this paper,an adaptive interval type-2 fuzzy controller is proposed for variable-speed and variable-pitch wind turbines.Because of attractive features of the well-known wind turbine baseline controller,the proposed...In this paper,an adaptive interval type-2 fuzzy controller is proposed for variable-speed and variable-pitch wind turbines.Because of attractive features of the well-known wind turbine baseline controller,the proposed controller acts as an augmented controller and works in parallel to the baseline controller.As typical variable-speed wind turbines have different controllers for different operation regions,for each operation region,a dedicated interval tvpe-2 fuzzy controller is designed.Because of the uncertainty in wind speed measurement,modern control techniques try to estimate this value.However,in contrast to these modern control techniques,the proposed controller is independent of the wind speed estimation.Thus,there is a better saving in cost and computational burden.To evaluate the effectiveness of the proposed controller,simulations are conducted with wind profiles which span all operation regions.Results show that,compared with the baseline controller,the proposed controller enhances power generations and reduces mechanical loads concurrently.展开更多
In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control...In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control strategy.Present the whole dynamic control model of variable-speed wind generator system in MATLAB/ Simulink,and the simulation results confirm the validity and effectiveness of the proposed control strategy.展开更多
This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain fie...This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain field.The impact of rainfall on aerodynamic performance was initially examined using a stationary turbine model in both wind and wind–rain conditions.Subsequently,the study compared the FOWT’s performance under various single degree-of-freedom(DOF)motions,including surge,pitch,heave,and yaw.Finally,the combined effects of wind–rain fields and platform motions involving two DOFs on the FOWT’s aerodynamics were analyzed and compared.The results demonstrate that rain negatively impacts the aerodynamic performance of both the stationary turbines and FOWTs.Pitch-dominated motions,whether involving single or multiple DOFs,caused significant fluctuations in the FOWT aerodynamics.The combination of surge and pitch motions created the most challenging operational environment for the FOWT in all tested scenarios.These findings highlighted the need for stronger construction materials and greater ultimate bearing capacity for FOWTs,as well as the importance of optimizing designs to mitigate excessive pitch and surge.展开更多
Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experi...Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.展开更多
To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid d...To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.展开更多
To enhance the prediction accuracy of unsteady wakes behind wind turbines,a novel reduced-order model is proposed by integrating a multifunctional recurrent fuzzy neural network(MFRFNN)and proper orthogonal decom-posi...To enhance the prediction accuracy of unsteady wakes behind wind turbines,a novel reduced-order model is proposed by integrating a multifunctional recurrent fuzzy neural network(MFRFNN)and proper orthogonal decom-position(POD).First,POD is employed to reduce the di-mensionality of the wind field data,extracting spatiotempo-rally correlated modal coefficients and modes.These reduced-order variables can effectively capture the essential features of unsteady wake behaviors.Next,MFRFNN is utilized to predict the time series of modal coefficients.Fi-nally,by combining the predicted modal coefficients with their corresponding modes,a flow field is reconstructed,al-lowing accurate prediction of unsteady wake dynamics.The predicted wake data exhibit high consistency with large eddy simulation results in both the near-and far-wake re-gions and outperform existing data-driven methods.This ap-proach offers significant potential for optimizing wind farm design and provides a new solution for the precise prediction of wind turbine wake behavior.展开更多
Anomaly detection in wind turbines involves emphasizing its ability to improve operational efficiency,reduce maintenance costs,extend their lifespan,and enhance reliability in the wind energy sector.This is particular...Anomaly detection in wind turbines involves emphasizing its ability to improve operational efficiency,reduce maintenance costs,extend their lifespan,and enhance reliability in the wind energy sector.This is particularly necessary in offshore wind,currently one of the most critical assets for achieving sustainable energy generation goals,due to the harsh marine environment and the difficulty of maintenance tasks.To address this problem,this work proposes a data-driven methodology for detecting power generation anomalies in offshore wind turbines,using normalized and linearized operational data.The proposed framework transforms heterogeneous wind speed and power measurements into a unified scale,enabling the development of a new wind power index(WPi)that quantifies deviations from expected performance.Additionally,spatial and temporal coherence analyses of turbines within a wind farm ensure the validity of these normalized measurements across different wind turbine models and operating conditions.Furthermore,a Support Vector Machine(SVM)refines the classification process,effectively distinguishing measurement errors from actual power generation failures.Validation of this strategy using real-world data from the Alpha Ventus wind farm demonstrates that the proposed approach not only improves predictive maintenance but also optimizes energy production,highlighting its potential for broad application in offshore wind installations.展开更多
This review provides a comprehensive and systematic examination of Computational Fluid Dynamics(CFD)techniques and methodologies applied to the development of Vertical Axis Wind Turbines(VAWTs).Although VAWTs offer si...This review provides a comprehensive and systematic examination of Computational Fluid Dynamics(CFD)techniques and methodologies applied to the development of Vertical Axis Wind Turbines(VAWTs).Although VAWTs offer significant advantages for urban wind applications,such as omnidirectional wind capture and a compact,ground-accessible design,they face substantial aerodynamic challenges,including dynamic stall,blade-wake interactions,and continuously varying angles of attack throughout their rotation.The review critically evaluates how CFD has been leveraged to address these challenges,detailing the modelling frameworks,simulation setups,mesh strategies,turbulence models,and boundary condition treatments adopted in the literature.Special attention is given to the comparative performance of 2-D vs.3-D simulations,static and dynamic meshing techniques(sliding,overset,morphing),and the impact of near-wall resolution on prediction fidelity.Moreover,this review maps the evolution of CFD tools in capturing key performance indicators including power coefficient,torque,flow separation,and wake dynamics,while highlighting both achievements and current limitations.The synthesis of studies reveals best practices,identifies gaps in simulation fidelity and validation strategies,and outlines critical directions for future research,particularly in high-fidelity modelling and cost-effective simulation of urban-scale VAWTs.By synthesizing insights from over a hundred referenced studies,this review serves as a consolidated resource to advance VAWT design and performance optimization through CFD.These include studies on various aspects such as blade geometry refinement,turbulence modeling,wake interaction mitigation,tip-loss reduction,dynamic stall control,and other aerodynamic and structural improvements.This,in turn,supports their broader integration into sustainable energy systems.展开更多
Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing nois...Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing noise generation.Efficiency,vibration,and noise levels can be optimized through morphing techniques applied to the blade’s shape,leading edge,trailing edge,and surface.Leading-edge morphing is particularly effective in improving efficiency and reducing noise,as flow attachment and separation at the leading edge significantly influence lift and vortex generation.Morphing technologies often draw inspiration from bionic designs based on natural phenomena,highlighting the potential of biomimicry to improve aerodynamic performance and energy capture.Understanding fluid-structure interactions is critical to ensuring the lifespan,performance,and safety of wind turbine blades,which directly affect operational efficiency and noise levels.This review underscores the importance of comprehending the interdependencies between aerodynamics,vibration,and noise to guide future research and policy in sustainable wind energy development.By summarizing key advancements in the field,this paper serves as a valuable resource for researchers,policymakers,and industry leaders involved in wind energy technologies.展开更多
Wind turbines are continuously exposed to harsh environmental and operational conditions throughout their lifetime,leading to the gradual degradation of their components.If left unaddressed,these degraded components c...Wind turbines are continuously exposed to harsh environmental and operational conditions throughout their lifetime,leading to the gradual degradation of their components.If left unaddressed,these degraded components can adversely affect turbine performance and significantly increase the likelihood of failure.As degradation progresses,the risk of failure escalates,making it essential to implement appropriate risk control measures.One effective risk control method involves performing inspection and monitoring activities that provide valuable insights into the condition of the structure,enabling the formulation of appropriate maintenance strategies based on accurate assessments.Supervisory Control and Data Acquisition(SCADA)systems offer low-resolution condition monitoring data that can be used for fault detection,diagnosis,quantification,prognosis,and maintenance planning.One commonly used method involves predicting power generation using SCADA data and comparing it against measured power generation.Significant discrepancies between predicted and measured values can indicate suboptimal operation,natural aging,or unnatural faults.Various predictive models,including parametric and non-parametric(statistical)approaches,have been proposed for estimating power generation.However,the imperfect nature of these models introduces uncertainties in the predicted power output.Additionally,SCADA monitoring data is prone to uncertainties arising from various sources.The presence of uncertainties from these two sources-imperfect predictive models and imperfect SCADA data-introduces uncertainty in the predicted power generation.This uncertainty complicates the process of determining whether discrepancies between measured and predicted values are significant enough to warrant maintenance actions.Depending on the nature of uncertainty-aleatory,arising from inherent randomness,or epistemic,stemming from incomplete knowledge or limited data-different analytical approaches,like Probabilistic and Possibilistic,can be applied for effective management.Both,Probabilistic and Possibilistic,Approaches offer distinct advantages and limitations.The Possibilistic Approach,rooted in fuzzy set theory,is particularly well suited for addressing epistemic uncertainties,especially those caused by imprecision or sparse statistical information.This makes it especially relevant for applications such as wind turbines,where it is often challenging to construct accurate probability distribution functions for environmental parameters due to limited sensor data from hard-to-access locations.This research focuses on developing a methodology for identifying suboptimal operation in wind turbines by comparing Grid Produced Power(Measured Produced Power)with Predicted Produced Power.To achieve this,the paper introduces a Possibilistic Approach for power prediction that accounts for uncertainties stemming from both model imperfections and measurement errors in SCADA data.The methodology combines machine learning models,used to establish predictive relationships between environmental inputs and power output,with a Possibilistic Framework that represents uncertainty through possibility distribution functions based on fuzzy logic and interval analysis.A real-world case study using operational SCADA data demonstrates the approach,with XGBoost selected as the final predictive model due to its strong accuracy and computational efficiency.展开更多
Active disturbance rejection control(ADRC)exhibits notable resilience against both internal and external disturbances.Its straightforward implementation further enhances its appeal for controlling a diverse class of s...Active disturbance rejection control(ADRC)exhibits notable resilience against both internal and external disturbances.Its straightforward implementation further enhances its appeal for controlling a diverse class of systems.However,the high-gain nature of the extended state observer,which is the core of ADRC,may degrade performance when faced with high-frequency sensing noise—a common challenge in real-world settings.This article addresses this issue through a specifically placed and particularly designed low-pass filterwhile preserving the ease of implementation characteristic of ADRC.This article proposes a simple tuning method for the filter-controller structure to improve the scheme’s design process.Theoretical results simplify the design process based on the Routh–Hurwitz criterion such that the additional low-pass filter does not affect the closedloop stability.The maximum power point tracking task on a wind turbine—a nonlinear system requiring the measurement of inherently noisy signals,such as electrical currents—is addressed to illustrate the design process of the proposed approach.Real-time experiments on a laboratory platform emulating a Permanent Magnet Synchronous Generator-based wind turbine endorse the enhanced scheme’s effectiveness in mitigating high-frequency sensing noise.展开更多
Biomimetics has recently emerged as an interesting approach to enhance renewable energy technologies.In this work,bioinspired Trailing Edge Serrations(TES)were evaluated on a typical Vertical Axis Wind Turbine(VAWT)ai...Biomimetics has recently emerged as an interesting approach to enhance renewable energy technologies.In this work,bioinspired Trailing Edge Serrations(TES)were evaluated on a typical Vertical Axis Wind Turbine(VAWT)airfoil,the DU06-W200.As noise reduction benefits of these mechanisms are already well-established,this study focuses on their impact on airfoil and VAWT performance.A saw-tooth geometry was chosen based on VAWT specifications and existing research,followed by a detailed assessment through wind tunnel tests using a newly developed aerodynamic balance.For a broad spectrum of attack angles and Reynolds numbers,lift,drag,and pitching moments were carefully measured.The results show that TES enhance the lift-to-drag ratio,especially in stalled conditions,and postpone stall at negative angles,expanding the effective performance range.A notable increase in pitching moment also is also observed,relevant for blade-strut joint design.Additionally,the impact on turbine performance was estimated using an analytical model,demonstrating excellent accuracy when compared against previous experimental results.TES offer a modest 2%improve-ment in peak performance,though they slightly narrow the optimal tip-speed ratio zone.Despite this,the potential noise reduction and performance gains make TES a valuable addition to VAWT designs,especially in urban settings.展开更多
Within the context of global energy transitions,many wind turbines have been installed in desert and Gobi regions.Nevertheless,the impact of turbulence characteristics in actual sand-laden atmospheric flows on the aer...Within the context of global energy transitions,many wind turbines have been installed in desert and Gobi regions.Nevertheless,the impact of turbulence characteristics in actual sand-laden atmospheric flows on the aerodynamic performance of wind turbines has not been evaluated.The current study employs the high-quality wind velocity data measured in the Qingtu Lake Observation Array station of Min Qin to reveal the effects of turbulence characteristics in sand-laden atmospheric flows on the power and loads of a small wind turbine.The results demonstrate that turbulent coherent structures under sand-laden conditions occur more frequently and with shorter durations than that under the unladen conditions,leading to frequent and large fluctuations of wind turbine loads,specifically,the power,thrust,and blade root flapwise moment increased by 238%,167%,and 194%,respectively.The predictions by applying the extreme turbulence model suggested that the maximum extreme thrust,blade root flapwise moment,and blade root edgewise moment of wind turbine under sand-laden conditions are 23%,19%,and 7%higher than that under unladen conditions.This study is expected to provide a basic supply for wind turbine design and siting decisions in sand-laden environment.展开更多
This study investigates the effect of nacelle motions on the rotor performance and drivetrain dynamics of floating offshore wind turbines(FOWTs)through fully coupled aero-hydro-elastic-servo-mooring simulations.Using ...This study investigates the effect of nacelle motions on the rotor performance and drivetrain dynamics of floating offshore wind turbines(FOWTs)through fully coupled aero-hydro-elastic-servo-mooring simulations.Using the National Renewable Energy Laboratory 5 MW monopile-supported offshore wind turbine and the OC4 DeepCwind semisubmersible wind turbine as case studies,the research addresses the complex dynamic responses resulting from the interaction among wind,waves,and turbine structures.Detailed multi-body dynamics models of wind turbines,including drivetrain components,are created within the SIMPACK framework.Meanwhile,the mooring system is modeled using a lumped-mass method.Various operational conditions are simulated through five wind-wave load cases.Results demonstrate that nacelle motions significantly influence rotor speed,thrust,torque,and power output,as well as the dynamic loads on drivetrain components.These findings highlight the need for advanced simulation techniques for the design and optimization of FOWTs to ensure reliable performance and longevity.展开更多
With the rapid advancement of machine learning technology and its growing adoption in research and engineering applications,an increasing number of studies have embraced data-driven approaches for modeling wind turbin...With the rapid advancement of machine learning technology and its growing adoption in research and engineering applications,an increasing number of studies have embraced data-driven approaches for modeling wind turbine wakes.These models leverage the ability to capture complex,high-dimensional characteristics of wind turbine wakes while offering significantly greater efficiency in the prediction process than physics-driven models.As a result,data-driven wind turbine wake models are regarded as powerful and effective tools for predicting wake behavior and turbine power output.This paper aims to provide a concise yet comprehensive review of existing studies on wind turbine wake modeling that employ data-driven approaches.It begins by defining and classifying machine learning methods to facilitate a clearer understanding of the reviewed literature.Subsequently,the related studies are categorized into four key areas:wind turbine power prediction,data-driven analytic wake models,wake field reconstruction,and the incorporation of explicit physical constraints.The accuracy of data-driven models is influenced by two primary factors:the quality of the training data and the performance of the model itself.Accordingly,both data accuracy and model structure are discussed in detail within the review.展开更多
Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly...Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly limits the accuracy of numerical analyses and finite element simulations. Therefore, this paper takes a new type of floating wind turbine as an example and performs a physical model test on the wave slamming characteristics of this floating wind turbine.Based on a 1:50 model of the Pivot Buoy floating wind turbine, an experimental study is performed under the combined effects of wind-wave loads on the peak pressure, duration, and pressure distribution of slamming. First, two sets of mooring systems, the combined scheme and the full mooring chain scheme, are designed to conduct a series of experimental studies of model slamming under different wind and wave incidence angles, wave heights, and wave periods. By doing so, the slamming characteristics of the wind turbine can be obtained. Moreover, to solve the problem of the large pitch motion response of the prototype wind turbine, a set of vertically oscillating structures is designed,and the slamming pressure characteristics of the optimized model are also investigated through model tests.展开更多
In recent years,offshore wind turbines have rap-idly developed,and many pile foundations installed earlier are now approaching decommissioning.Thus,the efficient removal of pile foundations has become a critical issue...In recent years,offshore wind turbines have rap-idly developed,and many pile foundations installed earlier are now approaching decommissioning.Thus,the efficient removal of pile foundations has become a critical issue for the sustainable development of offshore wind energy.To ad-dress this issue,this paper systematically investigates three methods for the recovery of pile foundations using physical model experiments:water injection+lifting,air injection+lifting,and air retention+water injection.The experimental results show that the water injection+lifting method exhibits remarkable advantages in recovering large-diameter and in-clined pile foundations;however,realigning inclined piles during recovery remains challenging,and a risk of pile over-turning exists.The air injection+lifting method proves ef-fective for realigning inclined piles but presents a risk of air expulsion failure,which may affect the continuity and stabil-ity of the recovery process.By contrast,the air retention+water injection method combines the characteristics of water injection and air injection techniques,effectively avoiding air expulsion failure and exhibiting pronounced displacement jumps during pile uplift.These findings provide a valuable reference for future decommissioning practices of offshore wind pile foundations,offer important engineering applica-tion value,and contribute positively to the sustainable devel-opment of the offshore wind industry.展开更多
文摘Maximizing the power capture is an important issue to the turbines that are installed in low wind speed area. In this paper, we focused on the modeling and control of variable speed wind turbine that is composed of two-mass drive train, a Squirrel Cage Induction Generator (SCIG), and voltage source converter control by Space Vector Pulse Width Modulation (SPVWM). To achieve Maximum Power Point Tracking (MPPT), the reference speed to the generator is searched via Extremum Seeking Control (ESC). ESC was designed for wind turbine region II operation based on dither-modulation scheme. ESC is a model-free method that has the ability to increase the captured power in real time under turbulent wind without any requirement for wind measurements. The controller is designed in two loops. In the outer loop, ESC is used to set a desired reference speed to PI controller to regulate the speed of the generator and extract the maximum electrical power. The inner control loop is based on Indirect Field Orientation Control (IFOC) to decouple the currents. Finally, Particle Swarm Optimization (PSO) is used to obtain the optimal PI parameters. Simulation and control of the system have been accomplished using MATLAB/Simulink 2014.
基金This work was supported by the National Natural Science Foundation of China(No.61803393)the Natural Science Foundation of Hunan Province(No.2020JJ4751)the Basic Science Research Program through the National Research Foundation(NRF)of Korea funded by the Ministry of Education(No.NRF-2016R1A6A1A03013567).
文摘This letter presents a systematic approach to estimate the annual energy production(AEP) of variable-speed wind turbines erected at high-altitude sites. Compared with the existing empirical-model based approaches, the proposed approach models the influence of the air density on the power production while employing the theoretical power curve. Consequently, the proposed approach provides a precise estimation of AEP, which can serve as a foundation of the optimum turbinesite matching design at different-altitude sites.
基金supported by the National Natural Science Foundation of China (No. 61803393)the Natural Science Foundation of Hunan Province (No.2020JJ4751)+1 种基金the Innovation-Driven Project of Central South University (No.2020CX031)the Basic Science Research Program of Korea (No. NRF-2016R1A6A1A03013567)。
文摘Due to varying characteristics of the wind condition, the performance of the wind turbines can be optimized by adapting the parameters of the control system. In this letter, an adaptive technique is proposed for the novel model predictive control(MPC) for the yaw system of the wind turbines. The control horizon is adapted to the one with the best predictive performance among multiple control horizons. The adaptive MPC is demonstrated by simulations using real wind data, and its performance is compared with the baseline MPC at fixed control horizon. Results show that the adaptive MPC provides better comprehensive performance than the baseline ones at different preview time of wind directions. Therefore, the proposed adaptive technique is potentially useful for the wind turbines in the future.
文摘In this paper,an adaptive interval type-2 fuzzy controller is proposed for variable-speed and variable-pitch wind turbines.Because of attractive features of the well-known wind turbine baseline controller,the proposed controller acts as an augmented controller and works in parallel to the baseline controller.As typical variable-speed wind turbines have different controllers for different operation regions,for each operation region,a dedicated interval tvpe-2 fuzzy controller is designed.Because of the uncertainty in wind speed measurement,modern control techniques try to estimate this value.However,in contrast to these modern control techniques,the proposed controller is independent of the wind speed estimation.Thus,there is a better saving in cost and computational burden.To evaluate the effectiveness of the proposed controller,simulations are conducted with wind profiles which span all operation regions.Results show that,compared with the baseline controller,the proposed controller enhances power generations and reduces mechanical loads concurrently.
文摘In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control strategy.Present the whole dynamic control model of variable-speed wind generator system in MATLAB/ Simulink,and the simulation results confirm the validity and effectiveness of the proposed control strategy.
基金Supported by the National Natural Science Foundation of China(51679080 and 51379073)the Fundamental Research Funds for the Central Universities(B230205020).
文摘This study employed a computational fluid dynamics model with an overset mesh technique to investigate the thrust and power of a floating offshore wind turbine(FOWT)under platform floating motion in the wind–rain field.The impact of rainfall on aerodynamic performance was initially examined using a stationary turbine model in both wind and wind–rain conditions.Subsequently,the study compared the FOWT’s performance under various single degree-of-freedom(DOF)motions,including surge,pitch,heave,and yaw.Finally,the combined effects of wind–rain fields and platform motions involving two DOFs on the FOWT’s aerodynamics were analyzed and compared.The results demonstrate that rain negatively impacts the aerodynamic performance of both the stationary turbines and FOWTs.Pitch-dominated motions,whether involving single or multiple DOFs,caused significant fluctuations in the FOWT aerodynamics.The combination of surge and pitch motions created the most challenging operational environment for the FOWT in all tested scenarios.These findings highlighted the need for stronger construction materials and greater ultimate bearing capacity for FOWTs,as well as the importance of optimizing designs to mitigate excessive pitch and surge.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2021YFB2601100)the National Natural Science Foundation of China (Grant No. 51979190)。
文摘Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.
文摘To improve the vertical axis wind turbine(VAWT)design,the angle of attack(AOA)and airfoil data must be treated correctly.The present paper develops a method for determining AOA on a VAWT based on computational fluid dynamics(CFD)analysis.First,a CFD analysis of a two-bladed VAWT equipped with a NACA 0012 airfoil is conducted.The thrust and power coefficients are validated through experiments.Second,the blade force and velocity data at monitoring points are collected.The AOA at different azimuth angles is determined by removing the blade self-induction at the monitoring point.Then,the lift and drag coefficients as a function of AOA are extracted.Results show that this method is independent of the monitoring points selection located at certain distance to the blades and the extracted dynamic stall hysteresis is more precise than the one with the“usual”method without considering the self-induction from bound vortices.
基金The National Natural Science Foundation of China (No. 51908107)。
文摘To enhance the prediction accuracy of unsteady wakes behind wind turbines,a novel reduced-order model is proposed by integrating a multifunctional recurrent fuzzy neural network(MFRFNN)and proper orthogonal decom-position(POD).First,POD is employed to reduce the di-mensionality of the wind field data,extracting spatiotempo-rally correlated modal coefficients and modes.These reduced-order variables can effectively capture the essential features of unsteady wake behaviors.Next,MFRFNN is utilized to predict the time series of modal coefficients.Fi-nally,by combining the predicted modal coefficients with their corresponding modes,a flow field is reconstructed,al-lowing accurate prediction of unsteady wake dynamics.The predicted wake data exhibit high consistency with large eddy simulation results in both the near-and far-wake re-gions and outperform existing data-driven methods.This ap-proach offers significant potential for optimizing wind farm design and provides a new solution for the precise prediction of wind turbine wake behavior.
基金supported by the Spanish Ministry of Science and Innovation under the MCI/AEI/FEDER project number PID2021-123543OBC21.
文摘Anomaly detection in wind turbines involves emphasizing its ability to improve operational efficiency,reduce maintenance costs,extend their lifespan,and enhance reliability in the wind energy sector.This is particularly necessary in offshore wind,currently one of the most critical assets for achieving sustainable energy generation goals,due to the harsh marine environment and the difficulty of maintenance tasks.To address this problem,this work proposes a data-driven methodology for detecting power generation anomalies in offshore wind turbines,using normalized and linearized operational data.The proposed framework transforms heterogeneous wind speed and power measurements into a unified scale,enabling the development of a new wind power index(WPi)that quantifies deviations from expected performance.Additionally,spatial and temporal coherence analyses of turbines within a wind farm ensure the validity of these normalized measurements across different wind turbine models and operating conditions.Furthermore,a Support Vector Machine(SVM)refines the classification process,effectively distinguishing measurement errors from actual power generation failures.Validation of this strategy using real-world data from the Alpha Ventus wind farm demonstrates that the proposed approach not only improves predictive maintenance but also optimizes energy production,highlighting its potential for broad application in offshore wind installations.
基金funded by Ministry of Higher Education Malaysia under the Fundamental Research Grant Scheme(FRGS/1/2024/TK10/UKM/02/7).
文摘This review provides a comprehensive and systematic examination of Computational Fluid Dynamics(CFD)techniques and methodologies applied to the development of Vertical Axis Wind Turbines(VAWTs).Although VAWTs offer significant advantages for urban wind applications,such as omnidirectional wind capture and a compact,ground-accessible design,they face substantial aerodynamic challenges,including dynamic stall,blade-wake interactions,and continuously varying angles of attack throughout their rotation.The review critically evaluates how CFD has been leveraged to address these challenges,detailing the modelling frameworks,simulation setups,mesh strategies,turbulence models,and boundary condition treatments adopted in the literature.Special attention is given to the comparative performance of 2-D vs.3-D simulations,static and dynamic meshing techniques(sliding,overset,morphing),and the impact of near-wall resolution on prediction fidelity.Moreover,this review maps the evolution of CFD tools in capturing key performance indicators including power coefficient,torque,flow separation,and wake dynamics,while highlighting both achievements and current limitations.The synthesis of studies reveals best practices,identifies gaps in simulation fidelity and validation strategies,and outlines critical directions for future research,particularly in high-fidelity modelling and cost-effective simulation of urban-scale VAWTs.By synthesizing insights from over a hundred referenced studies,this review serves as a consolidated resource to advance VAWT design and performance optimization through CFD.These include studies on various aspects such as blade geometry refinement,turbulence modeling,wake interaction mitigation,tip-loss reduction,dynamic stall control,and other aerodynamic and structural improvements.This,in turn,supports their broader integration into sustainable energy systems.
文摘Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing noise generation.Efficiency,vibration,and noise levels can be optimized through morphing techniques applied to the blade’s shape,leading edge,trailing edge,and surface.Leading-edge morphing is particularly effective in improving efficiency and reducing noise,as flow attachment and separation at the leading edge significantly influence lift and vortex generation.Morphing technologies often draw inspiration from bionic designs based on natural phenomena,highlighting the potential of biomimicry to improve aerodynamic performance and energy capture.Understanding fluid-structure interactions is critical to ensuring the lifespan,performance,and safety of wind turbine blades,which directly affect operational efficiency and noise levels.This review underscores the importance of comprehending the interdependencies between aerodynamics,vibration,and noise to guide future research and policy in sustainable wind energy development.By summarizing key advancements in the field,this paper serves as a valuable resource for researchers,policymakers,and industry leaders involved in wind energy technologies.
文摘Wind turbines are continuously exposed to harsh environmental and operational conditions throughout their lifetime,leading to the gradual degradation of their components.If left unaddressed,these degraded components can adversely affect turbine performance and significantly increase the likelihood of failure.As degradation progresses,the risk of failure escalates,making it essential to implement appropriate risk control measures.One effective risk control method involves performing inspection and monitoring activities that provide valuable insights into the condition of the structure,enabling the formulation of appropriate maintenance strategies based on accurate assessments.Supervisory Control and Data Acquisition(SCADA)systems offer low-resolution condition monitoring data that can be used for fault detection,diagnosis,quantification,prognosis,and maintenance planning.One commonly used method involves predicting power generation using SCADA data and comparing it against measured power generation.Significant discrepancies between predicted and measured values can indicate suboptimal operation,natural aging,or unnatural faults.Various predictive models,including parametric and non-parametric(statistical)approaches,have been proposed for estimating power generation.However,the imperfect nature of these models introduces uncertainties in the predicted power output.Additionally,SCADA monitoring data is prone to uncertainties arising from various sources.The presence of uncertainties from these two sources-imperfect predictive models and imperfect SCADA data-introduces uncertainty in the predicted power generation.This uncertainty complicates the process of determining whether discrepancies between measured and predicted values are significant enough to warrant maintenance actions.Depending on the nature of uncertainty-aleatory,arising from inherent randomness,or epistemic,stemming from incomplete knowledge or limited data-different analytical approaches,like Probabilistic and Possibilistic,can be applied for effective management.Both,Probabilistic and Possibilistic,Approaches offer distinct advantages and limitations.The Possibilistic Approach,rooted in fuzzy set theory,is particularly well suited for addressing epistemic uncertainties,especially those caused by imprecision or sparse statistical information.This makes it especially relevant for applications such as wind turbines,where it is often challenging to construct accurate probability distribution functions for environmental parameters due to limited sensor data from hard-to-access locations.This research focuses on developing a methodology for identifying suboptimal operation in wind turbines by comparing Grid Produced Power(Measured Produced Power)with Predicted Produced Power.To achieve this,the paper introduces a Possibilistic Approach for power prediction that accounts for uncertainties stemming from both model imperfections and measurement errors in SCADA data.The methodology combines machine learning models,used to establish predictive relationships between environmental inputs and power output,with a Possibilistic Framework that represents uncertainty through possibility distribution functions based on fuzzy logic and interval analysis.A real-world case study using operational SCADA data demonstrates the approach,with XGBoost selected as the final predictive model due to its strong accuracy and computational efficiency.
文摘Active disturbance rejection control(ADRC)exhibits notable resilience against both internal and external disturbances.Its straightforward implementation further enhances its appeal for controlling a diverse class of systems.However,the high-gain nature of the extended state observer,which is the core of ADRC,may degrade performance when faced with high-frequency sensing noise—a common challenge in real-world settings.This article addresses this issue through a specifically placed and particularly designed low-pass filterwhile preserving the ease of implementation characteristic of ADRC.This article proposes a simple tuning method for the filter-controller structure to improve the scheme’s design process.Theoretical results simplify the design process based on the Routh–Hurwitz criterion such that the additional low-pass filter does not affect the closedloop stability.The maximum power point tracking task on a wind turbine—a nonlinear system requiring the measurement of inherently noisy signals,such as electrical currents—is addressed to illustrate the design process of the proposed approach.Real-time experiments on a laboratory platform emulating a Permanent Magnet Synchronous Generator-based wind turbine endorse the enhanced scheme’s effectiveness in mitigating high-frequency sensing noise.
基金The authors wish to thank the financial support of the Spanish Ministry of Science,Innovation and Universities in reference to the Project:Efficiency improvement and noise reduction of a vertical axis wind turbine for urban environments(MERTURB)-Ref.MCINN-22-TED2021-131307B-100.
文摘Biomimetics has recently emerged as an interesting approach to enhance renewable energy technologies.In this work,bioinspired Trailing Edge Serrations(TES)were evaluated on a typical Vertical Axis Wind Turbine(VAWT)airfoil,the DU06-W200.As noise reduction benefits of these mechanisms are already well-established,this study focuses on their impact on airfoil and VAWT performance.A saw-tooth geometry was chosen based on VAWT specifications and existing research,followed by a detailed assessment through wind tunnel tests using a newly developed aerodynamic balance.For a broad spectrum of attack angles and Reynolds numbers,lift,drag,and pitching moments were carefully measured.The results show that TES enhance the lift-to-drag ratio,especially in stalled conditions,and postpone stall at negative angles,expanding the effective performance range.A notable increase in pitching moment also is also observed,relevant for blade-strut joint design.Additionally,the impact on turbine performance was estimated using an analytical model,demonstrating excellent accuracy when compared against previous experimental results.TES offer a modest 2%improve-ment in peak performance,though they slightly narrow the optimal tip-speed ratio zone.Despite this,the potential noise reduction and performance gains make TES a valuable addition to VAWT designs,especially in urban settings.
基金supported by the National Natural Science Foundation of China(Grant Nos.52276197 and 52166014)Gansu Province Key Research and Development Program-Industrial Project(Grant No.23YFGA0069)the National Key Research and Development Plan(Grant No.20t22YFB4202102-04).
文摘Within the context of global energy transitions,many wind turbines have been installed in desert and Gobi regions.Nevertheless,the impact of turbulence characteristics in actual sand-laden atmospheric flows on the aerodynamic performance of wind turbines has not been evaluated.The current study employs the high-quality wind velocity data measured in the Qingtu Lake Observation Array station of Min Qin to reveal the effects of turbulence characteristics in sand-laden atmospheric flows on the power and loads of a small wind turbine.The results demonstrate that turbulent coherent structures under sand-laden conditions occur more frequently and with shorter durations than that under the unladen conditions,leading to frequent and large fluctuations of wind turbine loads,specifically,the power,thrust,and blade root flapwise moment increased by 238%,167%,and 194%,respectively.The predictions by applying the extreme turbulence model suggested that the maximum extreme thrust,blade root flapwise moment,and blade root edgewise moment of wind turbine under sand-laden conditions are 23%,19%,and 7%higher than that under unladen conditions.This study is expected to provide a basic supply for wind turbine design and siting decisions in sand-laden environment.
基金Supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission of China(Grant No.:KJQN202301105,KJQN202101550)Scientific Research Fund of Chongqing University of Technology(grant No.2021ZDZ015)National Nature Science Foundation of China(No.:52205052).
文摘This study investigates the effect of nacelle motions on the rotor performance and drivetrain dynamics of floating offshore wind turbines(FOWTs)through fully coupled aero-hydro-elastic-servo-mooring simulations.Using the National Renewable Energy Laboratory 5 MW monopile-supported offshore wind turbine and the OC4 DeepCwind semisubmersible wind turbine as case studies,the research addresses the complex dynamic responses resulting from the interaction among wind,waves,and turbine structures.Detailed multi-body dynamics models of wind turbines,including drivetrain components,are created within the SIMPACK framework.Meanwhile,the mooring system is modeled using a lumped-mass method.Various operational conditions are simulated through five wind-wave load cases.Results demonstrate that nacelle motions significantly influence rotor speed,thrust,torque,and power output,as well as the dynamic loads on drivetrain components.These findings highlight the need for advanced simulation techniques for the design and optimization of FOWTs to ensure reliable performance and longevity.
基金Supported by the National Natural Science Foundation of China under Grant No.52131102.
文摘With the rapid advancement of machine learning technology and its growing adoption in research and engineering applications,an increasing number of studies have embraced data-driven approaches for modeling wind turbine wakes.These models leverage the ability to capture complex,high-dimensional characteristics of wind turbine wakes while offering significantly greater efficiency in the prediction process than physics-driven models.As a result,data-driven wind turbine wake models are regarded as powerful and effective tools for predicting wake behavior and turbine power output.This paper aims to provide a concise yet comprehensive review of existing studies on wind turbine wake modeling that employ data-driven approaches.It begins by defining and classifying machine learning methods to facilitate a clearer understanding of the reviewed literature.Subsequently,the related studies are categorized into four key areas:wind turbine power prediction,data-driven analytic wake models,wake field reconstruction,and the incorporation of explicit physical constraints.The accuracy of data-driven models is influenced by two primary factors:the quality of the training data and the performance of the model itself.Accordingly,both data accuracy and model structure are discussed in detail within the review.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071161)。
文摘Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly limits the accuracy of numerical analyses and finite element simulations. Therefore, this paper takes a new type of floating wind turbine as an example and performs a physical model test on the wave slamming characteristics of this floating wind turbine.Based on a 1:50 model of the Pivot Buoy floating wind turbine, an experimental study is performed under the combined effects of wind-wave loads on the peak pressure, duration, and pressure distribution of slamming. First, two sets of mooring systems, the combined scheme and the full mooring chain scheme, are designed to conduct a series of experimental studies of model slamming under different wind and wave incidence angles, wave heights, and wave periods. By doing so, the slamming characteristics of the wind turbine can be obtained. Moreover, to solve the problem of the large pitch motion response of the prototype wind turbine, a set of vertically oscillating structures is designed,and the slamming pressure characteristics of the optimized model are also investigated through model tests.
基金The National Natural Science Foundation of China (No. 52171274)。
文摘In recent years,offshore wind turbines have rap-idly developed,and many pile foundations installed earlier are now approaching decommissioning.Thus,the efficient removal of pile foundations has become a critical issue for the sustainable development of offshore wind energy.To ad-dress this issue,this paper systematically investigates three methods for the recovery of pile foundations using physical model experiments:water injection+lifting,air injection+lifting,and air retention+water injection.The experimental results show that the water injection+lifting method exhibits remarkable advantages in recovering large-diameter and in-clined pile foundations;however,realigning inclined piles during recovery remains challenging,and a risk of pile over-turning exists.The air injection+lifting method proves ef-fective for realigning inclined piles but presents a risk of air expulsion failure,which may affect the continuity and stabil-ity of the recovery process.By contrast,the air retention+water injection method combines the characteristics of water injection and air injection techniques,effectively avoiding air expulsion failure and exhibiting pronounced displacement jumps during pile uplift.These findings provide a valuable reference for future decommissioning practices of offshore wind pile foundations,offer important engineering applica-tion value,and contribute positively to the sustainable devel-opment of the offshore wind industry.
