scholarly journals A framework for optimization of turbulent wind-farm boundary layers and application to optimal control of wind-farm energy extraction

2016 ◽  
Author(s):  
Johan Meyers ◽  
Wim Munters ◽  
Jay Goit
Keyword(s):  
Optimal Control ◽  
Boundary Layers ◽  
Wind Farm ◽  
Energy Extraction ◽  
Turbulent Wind

scholarly journals Optimal control of energy extraction in wind-farm boundary layers

2015 ◽  
Vol 768 ◽  
pp. 5-50 ◽  
Author(s):  
Jay P. Goit ◽  
Johan Meyers
Keyword(s):  
Boundary Layer ◽  
Optimal Control ◽  
Boundary Layers ◽  
Wind Turbines ◽  
Wind Farm ◽  
Large Eddy Simulations ◽  
Energy Extraction ◽  
Reynolds Stresses ◽  
Turbulent Dissipation ◽  
Large Eddy

In very large wind farms, the vertical interaction with the atmospheric boundary layer plays an important role, i.e. the total energy extraction is governed by the vertical transport of kinetic energy from higher regions in the boundary layer towards the turbine level. In the current study, we investigate optimal control of wind-farm boundary layers, considering the individual wind turbines as flow actuators, whose energy extraction can be dynamically regulated in time so as to optimally influence the flow field and the vertical energy transport. To this end, we use large-eddy simulations of a fully developed pressure-driven wind-farm boundary layer in a receding-horizon optimal control framework. For the optimization of the wind-turbine controls, a conjugate-gradient optimization method is used in combination with adjoint large-eddy simulations for the determination of the gradients of the cost functional. In a first control study, wind-farm energy extraction is optimized in an aligned wind farm. Results are accumulated over one hour of operation. We find that the energy extraction is increased by 16 % compared to the uncontrolled reference. This is directly related to an increase of the vertical fluxes of energy towards the wind turbines, and vertical shear stresses increase considerably. A further analysis, decomposing the total stresses into dispersive and Reynolds stresses, shows that the dispersive stresses increase drastically, and that the Reynolds stresses decrease on average, but increase in the wake region, leading to better wake recovery. We further observe also that turbulent dissipation levels in the boundary layer increase, and overall the outer layer of the boundary layer enters into a transient decelerating regime, while the inner layer and the turbine region attain a new statistically steady equilibrium within approximately one wind-farm through-flow time. Two additional optimal control cases study penalization of turbulent dissipation. For the current wind-farm geometry, it is found that the ratio between wind-farm energy extraction and turbulent boundary-layer dissipation remains roughly around 70 %, but can be slightly increased by a few per cent by penalizing the dissipation in the optimization objective. For a pressure-driven boundary layer in equilibrium, we estimate that such a shift can lead to an increase in wind-farm energy extraction of 6 %.

scholarly journals Optimal Control of Wind Farm Energy Extraction and Beyond

2018 ◽  
Vol 43 (3) ◽  
pp. 266-272
Author(s):  
Jay Prakash GOIT
Keyword(s):  
Optimal Control ◽  
Wind Farm ◽  
Energy Extraction

Market-oriented Optimal Control Strategy for an Integrated Energy Storage System and Wind Farm

2021 ◽  
Author(s):  
Sajad Esmaeili ◽  
Mohammad Amini ◽  
Amir Khorsandi ◽  
Seyed Hamid Fathi ◽  
Seyed Hossein Hosseinian ◽  
...  
Keyword(s):  
Optimal Control ◽  
Energy Storage ◽  
Control Strategy ◽  
Wind Farm ◽  
Storage System ◽  
Energy Storage System ◽  
Optimal Control Strategy

Wave Energy Extraction Maximization in Irregular Ocean Waves Using Pseudospectral Methods

2013 ◽  
Author(s):  
Daniel R. Herber ◽  
James T. Allison
Keyword(s):  
Optimal Control ◽  
Resonance Frequency ◽  
Wave Energy ◽  
Energy Production ◽  
Early Stage ◽  
Wave Spectrum ◽  
Ocean Waves ◽  
Irregular Waves ◽  
Energy Extraction ◽  
Control Approach

Energy extraction from ocean waves and conversion to electrical energy is a promising form of renewable energy, yet achieving economic viability of wave energy converters (WECs) has proven challenging. In this article, the design of a heaving cylinder WEC will be explored. The optimal plant (i.e. draft and radius) design space with respect to the design’s optimal control (i.e. power take-off trajectory) for maximum energy production is characterized. Irregular waves based on the Bretschneider wave spectrum are considered. The optimization problem was solved using a pseudospectral method, a direct optimal control approach that can incorporate practical design constraints, such as power flow, actuation force, and slamming. The results provide early-stage guidelines for WEC design. Results show the resonance frequency required for optimal energy production with a regular wave is quite different than the resonance frequency found for irregular waves; specifically, it is much higher.

Sign in / Sign up

Export Citation Format

Share Document