A system based on a PV-Wind will ensure better efficiency and flexibility using lower energy production.Today,plenty of work is being focussed on Doubly Fed Induction Generators(DFIG)utilized in wind energy systems.DF...A system based on a PV-Wind will ensure better efficiency and flexibility using lower energy production.Today,plenty of work is being focussed on Doubly Fed Induction Generators(DFIG)utilized in wind energy systems.DFIG is found to be the best option in the Wind Energy Conversion Systems(WECS)to mitigate the issues caused by power converters.In this work,a new Artificial Neural Network(ANN)is proposed with the Diffusion and Dispersal strategy that works on Maximum Power Point Tracking(MPPT)along with Wind Energy Conversion System(WECS)to minimize electrical faults.The controller focus was not just to increase performance but also to reduce damage owing to any phase to phase fault or Phase to phase to ground fault.To ensure optimal MPPT for the proposed WECS,ANN achieves the optimal PI controller parameters for the indirect control of active and reactive power of DFIG.The optimal allocation and size of the DGs within the distributed system and for MPPT control are obtained using a population of agents.The generated solutions are evaluated and on being successful,the agents test their hypothesis again to create a positive feedback mechanism.Simulations are carried out,and the proposed IoT framework efficiency indicates performance improvement and faster recovery against faults by 9 percent for phase to ground fault and by 7.35 percent for phase to phase fault.展开更多
The exploitation of wind energy is rapidly evolving and is manifested in the ever-expanding global network of offshore wind energy farms.For the Small Island Developing States of the Caribbean Sea(CS),harnessing this ...The exploitation of wind energy is rapidly evolving and is manifested in the ever-expanding global network of offshore wind energy farms.For the Small Island Developing States of the Caribbean Sea(CS),harnessing this mature technology is an important first step in the transition away from fossil fuels.This paper uses buoy and satellite observations of surface wind speed in the CS to estimate wind energy resources over the 2009–201911-year period and initiates hour-ahead forecasting using the long short-term memory(LSTM)network.Observations of wind power density(WPD)at the 100-m height showed a mean of approximately 1000 W/m^(2) in the Colombia Basin,though this value decreases radially to 600–800 W/m^(2) in the central CS to a minimum of approximately 250 W/m^(2) at its borders in the Venezuela Basin.The Caribbean Low-Level Jet(CLLJ)is also responsible for the waxing and waning of surface wind speed and as such,resource stability,though stable as estimated through monthly and seasonal coefficients of variation,is naturally governed by CLLJ activity.Using a commercially available offshore wind turbine,wind energy generation at four locations in the CS is estimated.Electricity production is greatest and most stable in the central CS than at either its eastern or western borders.Wind speed forecasts are also found to be more accurate at this location,and though technology currently restricts offshore wind turbines to shallow water,outward migration to and colonization of deeper water is an attractive option for energy exploitation.展开更多
Wind energy is one of the most promising and renewable energy sources;however,owing to the limitations of device structures,collecting low-speed wind energy by triboelectric nanogenerators(TENGs)is still a huge challe...Wind energy is one of the most promising and renewable energy sources;however,owing to the limitations of device structures,collecting low-speed wind energy by triboelectric nanogenerators(TENGs)is still a huge challenge.To solve this problem,an ultra-durable and highly efficient windmill-like hybrid nanogenerator(W-HNG)is developed.Herein,the W-HNG composes coupled TENG and electromagnetic generator(EMG)and adopts a rotational contact-separation mode.This unique design efficiently avoids the wear of friction materials and ensures a prolonged service life.Moreover,the generator group is separated from the wind-driven part,which successfully prevents rotation resistance induced by the friction between rotor and stator in the conventional structures,and realizes low-speed wind energy harvesting.Additionally,the output characteristics of TENG can be complementary to the different performance advantages of EMG to achieve a satisfactory power production.The device is successfully driven when the wind speed is 1.8 m s−1,and the output power of TENG and EMG can achieve 0.95 and 3.7 mW,respectively.After power management,the W-HNG has been successfully applied as a power source for electronic devices.This work provides a simple,reliable,and durable device for improved performance toward large-scale low-speed breeze energy harvesting.展开更多
Following the current rapid development of the Internet of Things(IoT)and wireless condition monitoring systems,energy harvesters which use ambient energy have become a key part of achieving an energy-autonomous syste...Following the current rapid development of the Internet of Things(IoT)and wireless condition monitoring systems,energy harvesters which use ambient energy have become a key part of achieving an energy-autonomous system.Miniature wind energy harvesters have attracted widespread attention because of their great potential of power density as well as the rich availability of wind energy in many possible areas of application.This article provides readers with a glimpse into the state-of-the-art of miniature wind energy harvesters.The crucial factors for them to achieve high working efficiency under lower operational wind speed excitation are analyzed.Various potential energy coupling mechanisms are discussed in detail.Design approaches for broadening operational wind-speed-range given a variety of energy coupling mechanisms are also presented,as observed in the literature.Performance enhancement mechanisms including hydrodynamic configuration optimization,and non-linear vibration pick-up structure are reviewed.Conclusions are drawn and the outlook for each coupling mechanisms is presented.展开更多
In this paper,a novel robust fault-tolerant control scheme based on event-triggered communication mechanism for a variable-speed wind energy conversion system(WECS)with sensor and actuator failures is proposed.The non...In this paper,a novel robust fault-tolerant control scheme based on event-triggered communication mechanism for a variable-speed wind energy conversion system(WECS)with sensor and actuator failures is proposed.The nonlinear WECS with event-triggered mechanism is modeled based on the Takagi-Sugeno(T-S)fuzzy model.By Lyapunov stability theory,the parameter expression of the proposed robust fault-tolerant controller with event-triggered mechanisms is proposed based on a feasible solution of linear matrix inequalities.Compared with the existing WECS fault-tolerant control methods,the proposed scheme significantly reduces the pressure of network packet transmission and improves the robustness and reliability of the WECS.Considering a doubly-fed variable speed constant frequency wind turbine,the eventtriggered mechanism based fault-tolerant control for WECS is analyzed considering system model uncertainty.Numerical simulation results demonstrate that the proposed scheme is feasible and effective.展开更多
Renewable energy has garnered attention due to the need for sustainable energy sources.Wind power has emerged as an alternative that has contributed to the transition towards cleaner energy.As the importance of wind e...Renewable energy has garnered attention due to the need for sustainable energy sources.Wind power has emerged as an alternative that has contributed to the transition towards cleaner energy.As the importance of wind energy grows,it can be crucial to provide forecasts that optimize its performance potential.Artificial intelligence(AI)methods have risen in prominence due to how well they can handle complicated systems while enhancing the accuracy of prediction.This study explored the area of AI to predict wind-energy production at a wind farm in Yalova,Turkey,using four different AI approaches:support vector machines(SVMs),decision trees,adaptive neuro-fuzzy inference systems(ANFIS)and artificial neural networks(ANNs).Wind speed and direction were considered as essential input parameters,with wind energy as the target parameter,and models are thoroughly evaluated using metrics such as the mean absolute percentage error(MAPE),coefficient of determination(R~2),and mean absolute error(MAE).The findings accentuate the superior performance of the SVM,which delivered the lowest MAPE(2.42%),the highest R~2(0.95),and the lowest MAE(71.21%)compared with actual values,while ANFIS was less effective in this context.The main aim of this comparative analysis was to rank the models to move to the next step in improving the least efficient methods by combining them with optimization algorithms,such as metaheuristic algorithms.展开更多
The energy conversion optimization control strategy is presented for a family of horizontal-axis variablespeed fixed-pitch wind energy conversion systems,working in the partial load region.The system uses a variablesp...The energy conversion optimization control strategy is presented for a family of horizontal-axis variablespeed fixed-pitch wind energy conversion systems,working in the partial load region.The system uses a variablespeed wind turbine(VSWT)driving a squirrel-cage induction generator(SCIG)connected to a grid.A new maximum power point tracking(MPPT)approach is proposed based on the extremum seeking control principles under the assumption that the wind turbine model and its parameters are poorly known.The aim is to drive the average position of the operation point close to optimality.Here the wind turbulence is used as search disturbance instead of inducing new sinusoidal search signals.The discrete Fourier transform(DFT)process of some available measures estimates the distance of operation point to optimality.The effectiveness of the proposed MPPT approach is validated under different operation conditions by numerical simulations in MATLAB/SIMULINK.The simulation results prove that the new approach can effectively suppress the vibration of system and enhance the dynamic performance of system.展开更多
The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem....The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem.This weak interconnection of wind generating source in the electrical network affects the power quality and reliability.The localized energy storages shall compensate the fluctuating power and support to strengthen the wind generator in the power system.In this paper,it is proposed to control the voltage source inverter （VSI） in current control mode with energy storage,that is,batteries across the dc bus.The generated wind power can be extracted under varying wind speed and stored in the batteries.This energy storage maintains the stiff voltage across the dc bus of the voltage source inverter.The proposed scheme enhances the stability and reliability of the power system and maintains unity power factor.It can also be operated in stand-alone mode in the power system.The power exchange across the wind generation and the load under dynamic situation is feasible while maintaining the power quality norms at the common point of coupling.It strengthens the weak grid in the power system.This control strategy is evaluated on the test system under dynamic condition by using simulation.The results are verified by comparing the performance of controllers.展开更多
Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy obser...Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.展开更多
With the growing need for renewable energy,wind farms are playing an important role in generating clean power from wind resources.The best wind turbine architecture in a wind farm has a major influence on the energy e...With the growing need for renewable energy,wind farms are playing an important role in generating clean power from wind resources.The best wind turbine architecture in a wind farm has a major influence on the energy extraction efficiency.This paper describes a unique strategy for optimizing wind turbine locations on a wind farm that combines the capabilities of particle swarm optimization(PSO)and artificial neural networks(ANNs).The PSO method was used to explore the solution space and develop preliminary turbine layouts,and the ANN model was used to fine-tune the placements based on the predicted energy generation.The proposed hybrid technique seeks to increase energy output while considering site-specific wind patterns and topographical limits.The efficacy and superiority of the hybrid PSO-ANN methodology are proved through comprehensive simulations and comparisons with existing approaches,giving exciting prospects for developing more efficient and sustainable wind farms.The integration of ANNs and PSO in our methodology is of paramount importance because it leverages the complementary strengths of both techniques.Furthermore,this novel methodology harnesses historical data through ANNs to identify optimal turbine positions that align with the wind speed and direction and enhance energy extraction efficiency.A notable increase in power generation is observed across various scenarios.The percentage increase in the power generation ranged from approximately 7.7%to 11.1%.Owing to its versatility and adaptability to site-specific conditions,the hybrid model offers promising prospects for advancing the field of wind farm layout optimization and contributing to a greener and more sustainable energy future.展开更多
Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different a...Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory （NREL） phase V1 wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface （AMI） method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.展开更多
Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to fi...Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to find a more accurate,economic and efficient approach,which can be utilized to predict the full-scale global dynamic responses of FOWTs.In this paper,a literature review of experimental-numerical methodologies and challenges for FOWTs is made.Several key challenges in the conventional basin experiment issues are discussed,including scaling issues;coupling effects between aero-hydro and structural dynamic responses;blade pitch control strategies;experimental facilities and calibration methods.Several basin experiments,industrial projects and numerical codes are summarized to demonstrate the progress of hybrid experimental methods.Besides,time delay in hardware-in-the-loop challenges is concluded to emphasize their significant role in real-time hybrid approaches.It is of great use to comprehend these methodologies and challenges,which can help some future researchers to make a footstone for proposing a more efficient and functional hybrid basin experimental and numerical method.展开更多
Purpose: This paper aims to point out the scientific development and research density of renewable energy sources such as photovoltaic, wind, and biomass, using a mix of computational tools. Based on this, it was poss...Purpose: This paper aims to point out the scientific development and research density of renewable energy sources such as photovoltaic, wind, and biomass, using a mix of computational tools. Based on this, it was possible to verify the existence of new research trends and opportunities in a macro view regarding management, performance evaluation, and decision-making in renewable energy generation systems and installations.Design/methodology/approach: A scientometric approach was used based on a research protocol to retrieve papers from the Scopus database, and through four scientometric questions, to analyze each area. Software such as the Science Mapping Analysis Software Tool(Sci MAT) and Sci2 Tool were used to map the science development and density.Findings: The scientific development of renewable energy areas is highlighted, pointing out research opportunities regarding management, studies on costs and investments, systemic diagnosis, and performance evaluation for decision-making in businesses in these areas.Research limitations: This paper was limited to the articles indexed in the Scopus database and by the questions used to analyze the scientific development of renewable energy areas.Practical implications: The results show the need for a managerial perspective in businesses related to renewable energy sources at the managerial, technical, and operational levels, including performance evaluation, assertive decision making, and adequate use of technical and financial resources.Originality/value: This paper shows that there is a research field to be explored, with gaps to fill and further research to be carried out in this area. Besides, this paper can serve as a basis for other studies and research in other areas and domains.展开更多
As global economic growth increases,the demand for energy sources boosts.While fossil fuels have traditionally satisfied this demand,their environmental influence and limited reserves require alternatives.Fossil fuel co...As global economic growth increases,the demand for energy sources boosts.While fossil fuels have traditionally satisfied this demand,their environmental influence and limited reserves require alternatives.Fossil fuel combustion contributes substantially to greenhouse gas emissions,with a pressing need to halve these emissions by 2030 and target net-zero by 2050.Renewable energy sources,contributing currently to 29%of global electricity,are viewed as promising substitutes.With wind energy's potential,Zheng's team developed a novel method to harness even low wind speeds using well-aligned nanofibers and an innovative“drop wind generator”.This system,combining moisture-saturated ionic liquid 3-Methyl-1-octylimidazolium chloride with specific nanofiber arrays,exploits wind-inducedflows for energy conversion.This study highlights the vast untapped potential of low-speed wind as a sustainable energy source potentially for electronics.展开更多
文摘A system based on a PV-Wind will ensure better efficiency and flexibility using lower energy production.Today,plenty of work is being focussed on Doubly Fed Induction Generators(DFIG)utilized in wind energy systems.DFIG is found to be the best option in the Wind Energy Conversion Systems(WECS)to mitigate the issues caused by power converters.In this work,a new Artificial Neural Network(ANN)is proposed with the Diffusion and Dispersal strategy that works on Maximum Power Point Tracking(MPPT)along with Wind Energy Conversion System(WECS)to minimize electrical faults.The controller focus was not just to increase performance but also to reduce damage owing to any phase to phase fault or Phase to phase to ground fault.To ensure optimal MPPT for the proposed WECS,ANN achieves the optimal PI controller parameters for the indirect control of active and reactive power of DFIG.The optimal allocation and size of the DGs within the distributed system and for MPPT control are obtained using a population of agents.The generated solutions are evaluated and on being successful,the agents test their hypothesis again to create a positive feedback mechanism.Simulations are carried out,and the proposed IoT framework efficiency indicates performance improvement and faster recovery against faults by 9 percent for phase to ground fault and by 7.35 percent for phase to phase fault.
文摘The exploitation of wind energy is rapidly evolving and is manifested in the ever-expanding global network of offshore wind energy farms.For the Small Island Developing States of the Caribbean Sea(CS),harnessing this mature technology is an important first step in the transition away from fossil fuels.This paper uses buoy and satellite observations of surface wind speed in the CS to estimate wind energy resources over the 2009–201911-year period and initiates hour-ahead forecasting using the long short-term memory(LSTM)network.Observations of wind power density(WPD)at the 100-m height showed a mean of approximately 1000 W/m^(2) in the Colombia Basin,though this value decreases radially to 600–800 W/m^(2) in the central CS to a minimum of approximately 250 W/m^(2) at its borders in the Venezuela Basin.The Caribbean Low-Level Jet(CLLJ)is also responsible for the waxing and waning of surface wind speed and as such,resource stability,though stable as estimated through monthly and seasonal coefficients of variation,is naturally governed by CLLJ activity.Using a commercially available offshore wind turbine,wind energy generation at four locations in the CS is estimated.Electricity production is greatest and most stable in the central CS than at either its eastern or western borders.Wind speed forecasts are also found to be more accurate at this location,and though technology currently restricts offshore wind turbines to shallow water,outward migration to and colonization of deeper water is an attractive option for energy exploitation.
基金The authors gratefully acknowledge the financial support from the Natural Science Foundation of Chongqing(Grant No.cstc2017jcyjAX0307)the Fundamental Research Funds for the Central Universities(Grant Nos.CYFH201821,2020CDCGJ005,2018CDQYWL0046,2019CDXZWL001)the National Natural Science Foundation of China(Grant No.51402112).
文摘Wind energy is one of the most promising and renewable energy sources;however,owing to the limitations of device structures,collecting low-speed wind energy by triboelectric nanogenerators(TENGs)is still a huge challenge.To solve this problem,an ultra-durable and highly efficient windmill-like hybrid nanogenerator(W-HNG)is developed.Herein,the W-HNG composes coupled TENG and electromagnetic generator(EMG)and adopts a rotational contact-separation mode.This unique design efficiently avoids the wear of friction materials and ensures a prolonged service life.Moreover,the generator group is separated from the wind-driven part,which successfully prevents rotation resistance induced by the friction between rotor and stator in the conventional structures,and realizes low-speed wind energy harvesting.Additionally,the output characteristics of TENG can be complementary to the different performance advantages of EMG to achieve a satisfactory power production.The device is successfully driven when the wind speed is 1.8 m s−1,and the output power of TENG and EMG can achieve 0.95 and 3.7 mW,respectively.After power management,the W-HNG has been successfully applied as a power source for electronic devices.This work provides a simple,reliable,and durable device for improved performance toward large-scale low-speed breeze energy harvesting.
基金the financial support from National Natural Science Foundation of China Grant No.61604023National Natural Science Foundation of China(Grant No.61804016)。
文摘Following the current rapid development of the Internet of Things(IoT)and wireless condition monitoring systems,energy harvesters which use ambient energy have become a key part of achieving an energy-autonomous system.Miniature wind energy harvesters have attracted widespread attention because of their great potential of power density as well as the rich availability of wind energy in many possible areas of application.This article provides readers with a glimpse into the state-of-the-art of miniature wind energy harvesters.The crucial factors for them to achieve high working efficiency under lower operational wind speed excitation are analyzed.Various potential energy coupling mechanisms are discussed in detail.Design approaches for broadening operational wind-speed-range given a variety of energy coupling mechanisms are also presented,as observed in the literature.Performance enhancement mechanisms including hydrodynamic configuration optimization,and non-linear vibration pick-up structure are reviewed.Conclusions are drawn and the outlook for each coupling mechanisms is presented.
基金supported by Ministry of Science and Technology of Peoples Republic of China(No.2019YFE0104800).
文摘In this paper,a novel robust fault-tolerant control scheme based on event-triggered communication mechanism for a variable-speed wind energy conversion system(WECS)with sensor and actuator failures is proposed.The nonlinear WECS with event-triggered mechanism is modeled based on the Takagi-Sugeno(T-S)fuzzy model.By Lyapunov stability theory,the parameter expression of the proposed robust fault-tolerant controller with event-triggered mechanisms is proposed based on a feasible solution of linear matrix inequalities.Compared with the existing WECS fault-tolerant control methods,the proposed scheme significantly reduces the pressure of network packet transmission and improves the robustness and reliability of the WECS.Considering a doubly-fed variable speed constant frequency wind turbine,the eventtriggered mechanism based fault-tolerant control for WECS is analyzed considering system model uncertainty.Numerical simulation results demonstrate that the proposed scheme is feasible and effective.
文摘Renewable energy has garnered attention due to the need for sustainable energy sources.Wind power has emerged as an alternative that has contributed to the transition towards cleaner energy.As the importance of wind energy grows,it can be crucial to provide forecasts that optimize its performance potential.Artificial intelligence(AI)methods have risen in prominence due to how well they can handle complicated systems while enhancing the accuracy of prediction.This study explored the area of AI to predict wind-energy production at a wind farm in Yalova,Turkey,using four different AI approaches:support vector machines(SVMs),decision trees,adaptive neuro-fuzzy inference systems(ANFIS)and artificial neural networks(ANNs).Wind speed and direction were considered as essential input parameters,with wind energy as the target parameter,and models are thoroughly evaluated using metrics such as the mean absolute percentage error(MAPE),coefficient of determination(R~2),and mean absolute error(MAE).The findings accentuate the superior performance of the SVM,which delivered the lowest MAPE(2.42%),the highest R~2(0.95),and the lowest MAE(71.21%)compared with actual values,while ANFIS was less effective in this context.The main aim of this comparative analysis was to rank the models to move to the next step in improving the least efficient methods by combining them with optimization algorithms,such as metaheuristic algorithms.
基金Supported by the National Basic Research Program("973" Program)(2007CB210303)the Research Funding of Nanjing University of Aeronautics and Astronautrics(NP2011011)
文摘The energy conversion optimization control strategy is presented for a family of horizontal-axis variablespeed fixed-pitch wind energy conversion systems,working in the partial load region.The system uses a variablespeed wind turbine(VSWT)driving a squirrel-cage induction generator(SCIG)connected to a grid.A new maximum power point tracking(MPPT)approach is proposed based on the extremum seeking control principles under the assumption that the wind turbine model and its parameters are poorly known.The aim is to drive the average position of the operation point close to optimality.Here the wind turbulence is used as search disturbance instead of inducing new sinusoidal search signals.The discrete Fourier transform(DFT)process of some available measures estimates the distance of operation point to optimality.The effectiveness of the proposed MPPT approach is validated under different operation conditions by numerical simulations in MATLAB/SIMULINK.The simulation results prove that the new approach can effectively suppress the vibration of system and enhance the dynamic performance of system.
文摘The wind energy generation,utilization and its grid penetration in electrical grid are increasing world-wide.The wind generated power is always fluctuating due to its time varying nature and causing stability problem.This weak interconnection of wind generating source in the electrical network affects the power quality and reliability.The localized energy storages shall compensate the fluctuating power and support to strengthen the wind generator in the power system.In this paper,it is proposed to control the voltage source inverter （VSI） in current control mode with energy storage,that is,batteries across the dc bus.The generated wind power can be extracted under varying wind speed and stored in the batteries.This energy storage maintains the stiff voltage across the dc bus of the voltage source inverter.The proposed scheme enhances the stability and reliability of the power system and maintains unity power factor.It can also be operated in stand-alone mode in the power system.The power exchange across the wind generation and the load under dynamic situation is feasible while maintaining the power quality norms at the common point of coupling.It strengthens the weak grid in the power system.This control strategy is evaluated on the test system under dynamic condition by using simulation.The results are verified by comparing the performance of controllers.
文摘Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.
文摘With the growing need for renewable energy,wind farms are playing an important role in generating clean power from wind resources.The best wind turbine architecture in a wind farm has a major influence on the energy extraction efficiency.This paper describes a unique strategy for optimizing wind turbine locations on a wind farm that combines the capabilities of particle swarm optimization(PSO)and artificial neural networks(ANNs).The PSO method was used to explore the solution space and develop preliminary turbine layouts,and the ANN model was used to fine-tune the placements based on the predicted energy generation.The proposed hybrid technique seeks to increase energy output while considering site-specific wind patterns and topographical limits.The efficacy and superiority of the hybrid PSO-ANN methodology are proved through comprehensive simulations and comparisons with existing approaches,giving exciting prospects for developing more efficient and sustainable wind farms.The integration of ANNs and PSO in our methodology is of paramount importance because it leverages the complementary strengths of both techniques.Furthermore,this novel methodology harnesses historical data through ANNs to identify optimal turbine positions that align with the wind speed and direction and enhance energy extraction efficiency.A notable increase in power generation is observed across various scenarios.The percentage increase in the power generation ranged from approximately 7.7%to 11.1%.Owing to its versatility and adaptability to site-specific conditions,the hybrid model offers promising prospects for advancing the field of wind farm layout optimization and contributing to a greener and more sustainable energy future.
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant Nos. 51379125, 51411130131, 11432009）, the National Key Basic Research Development Plan （973 Plan） Project of China （Grant No. 2013CB036103）, High Technology of Marine Research Project of the Ministry of Industry and Information Technology of China, ABS（China）, and the Program for Professor of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Learning （Grant No. 2013022）.
文摘Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory （NREL） phase V1 wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface （AMI） method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.
文摘Due to the dissimilar scaling issues,the conventional experimental method of FOWTs can hardly be used directly to validate the full-scale global dynamic responses accurately.Therefore,it is of absolute necessity to find a more accurate,economic and efficient approach,which can be utilized to predict the full-scale global dynamic responses of FOWTs.In this paper,a literature review of experimental-numerical methodologies and challenges for FOWTs is made.Several key challenges in the conventional basin experiment issues are discussed,including scaling issues;coupling effects between aero-hydro and structural dynamic responses;blade pitch control strategies;experimental facilities and calibration methods.Several basin experiments,industrial projects and numerical codes are summarized to demonstrate the progress of hybrid experimental methods.Besides,time delay in hardware-in-the-loop challenges is concluded to emphasize their significant role in real-time hybrid approaches.It is of great use to comprehend these methodologies and challenges,which can help some future researchers to make a footstone for proposing a more efficient and functional hybrid basin experimental and numerical method.
基金supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [grant numbers 142448/2018-4, 308723/2017-1, 311926/2017-7 and 465640/2014-1]Coordenacao de Aperfeicoamento de Pessoal de Nível Superior (CAPES) [grant number 23038.000776/2017-54]+2 种基金Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS) [grant number 17/2551-0000517-1]supported by a post doc grant of CAPES – Brazil (CAPES process Baierle No. 88887.464876/2019-00)CNPq, CAPES, FAPERGS and Institutos Nacionais de Ciência e Tecnologia – Gera■o Distribuída (INCT-GD) for supporting。
文摘Purpose: This paper aims to point out the scientific development and research density of renewable energy sources such as photovoltaic, wind, and biomass, using a mix of computational tools. Based on this, it was possible to verify the existence of new research trends and opportunities in a macro view regarding management, performance evaluation, and decision-making in renewable energy generation systems and installations.Design/methodology/approach: A scientometric approach was used based on a research protocol to retrieve papers from the Scopus database, and through four scientometric questions, to analyze each area. Software such as the Science Mapping Analysis Software Tool(Sci MAT) and Sci2 Tool were used to map the science development and density.Findings: The scientific development of renewable energy areas is highlighted, pointing out research opportunities regarding management, studies on costs and investments, systemic diagnosis, and performance evaluation for decision-making in businesses in these areas.Research limitations: This paper was limited to the articles indexed in the Scopus database and by the questions used to analyze the scientific development of renewable energy areas.Practical implications: The results show the need for a managerial perspective in businesses related to renewable energy sources at the managerial, technical, and operational levels, including performance evaluation, assertive decision making, and adequate use of technical and financial resources.Originality/value: This paper shows that there is a research field to be explored, with gaps to fill and further research to be carried out in this area. Besides, this paper can serve as a basis for other studies and research in other areas and domains.
基金funding of the National Natural Science Foundation of China(no.21776235,no.21376197)the studentship by the Hong Kong Polytechnic University。
文摘As global economic growth increases,the demand for energy sources boosts.While fossil fuels have traditionally satisfied this demand,their environmental influence and limited reserves require alternatives.Fossil fuel combustion contributes substantially to greenhouse gas emissions,with a pressing need to halve these emissions by 2030 and target net-zero by 2050.Renewable energy sources,contributing currently to 29%of global electricity,are viewed as promising substitutes.With wind energy's potential,Zheng's team developed a novel method to harness even low wind speeds using well-aligned nanofibers and an innovative“drop wind generator”.This system,combining moisture-saturated ionic liquid 3-Methyl-1-octylimidazolium chloride with specific nanofiber arrays,exploits wind-inducedflows for energy conversion.This study highlights the vast untapped potential of low-speed wind as a sustainable energy source potentially for electronics.
