Variable-speed wind power generation system usually adopts maximum power point tracking(MPPT)below the rated wind speed or constant power control above the rated wind speed.However,single objective control has large d...Variable-speed wind power generation system usually adopts maximum power point tracking(MPPT)below the rated wind speed or constant power control above the rated wind speed.However,single objective control has large dynamic loads on transmission systems.This paper presents a multi-objective control scheme for wind turbine in low wind speed,which achieves not only high power capture efficiency but also low fatigue load on mechanical parts.Input wind speed is separated into two components:a slowly varying seasonal component and a rapidly varying turbulent component.Correspondingly,the machine-side converter controller is divided into low frequency loop and high frequency loops.The low frequency loop implements MPPT control,the high frequency loop reduces the fluctuations of torque,and both loops together suppress the variations of output power.Simulation was conducted in Matlab/Simulink and FAST code was used to further verify the correctness of the multi-objective control strategy.展开更多
An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate v...An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate values of the scaling lengths associated with vortex shedding and shear layer frequencies to predict the power law relationship with Reynolds number. The predicted results are in good agreement with experimental results. The findings will provide a greater insight into the overall phenomenon involved.展开更多
基金Supported by the National Natural Science Foundation of China under Grants 51320105002 and 51577025.
文摘Variable-speed wind power generation system usually adopts maximum power point tracking(MPPT)below the rated wind speed or constant power control above the rated wind speed.However,single objective control has large dynamic loads on transmission systems.This paper presents a multi-objective control scheme for wind turbine in low wind speed,which achieves not only high power capture efficiency but also low fatigue load on mechanical parts.Input wind speed is separated into two components:a slowly varying seasonal component and a rapidly varying turbulent component.Correspondingly,the machine-side converter controller is divided into low frequency loop and high frequency loops.The low frequency loop implements MPPT control,the high frequency loop reduces the fluctuations of torque,and both loops together suppress the variations of output power.Simulation was conducted in Matlab/Simulink and FAST code was used to further verify the correctness of the multi-objective control strategy.
文摘An attempt has been made to explore whether the power relation can be obtained from theoretical considerations. The classical laminar and turbulent boundary layer concepts have been employed to determine appropriate values of the scaling lengths associated with vortex shedding and shear layer frequencies to predict the power law relationship with Reynolds number. The predicted results are in good agreement with experimental results. The findings will provide a greater insight into the overall phenomenon involved.
