Maximizing Wind Turbine Energy Capture via Extremum Seeking Control

2008 ◽  
Author(s):  
Justin Creaby ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Turbine ◽  
Torque Control ◽  
Extremum Seeking ◽  
Control Torque ◽  
Pass Filter ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Variable Speed Wind Turbine ◽  
Speed Up ◽  
High Pass

Maximizing wind turbine energy capture has become an important issue as more turbines are installed in low wind areas. This paper investigates the application of extremum seeking control (ESC) to maximizing the energy capture of variable speed wind turbine. The optimal control torque and pitch angle are searched via ESC based on the measurement of output power. The advantage is the independency from accurate wind measurement. Simulation has been conducted on FAST for a wind turbine dynamic model, under uniformly steady wind, stair-case wind speed variations, and turbulence wind. The simulation results indicated that the captured power increased by up to 4% over the standard torque control. Anti-windup ESC was then applied to overcome the actuation saturation which may disable the ESC process. Finally, the ESC with high-pass filter input resetting was applied to speed up the transient under abrupt change of wind.

Real-Time Optimization of Wind Farm Energy Capture With Delay Compensated Nested-Loop Extremum Seeking Control

2017 ◽  
Author(s):  
Zhongyou Wu ◽  
Yaoyu Li
Keyword(s):  
Wind Turbine ◽  
Real Time ◽  
Wind Farm ◽  
Optimization Techniques ◽  
Extremum Seeking ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Time Optimization ◽  
Real Time Optimization ◽  
Nested Loop

Real-time optimization of wind farm energy capture for below rated wind speed is critical for reducing the levelized cost of energy (LCOE). Performance of model based control and optimization techniques can be significantly limited by the difficulty in obtaining accurate turbine and farm models in field operation, as well as the prohibitive cost for accurate wind measurements. The Nested-Loop Extremum Seeking Control (NLESC), recently proposed as a model free method has demonstrated its great potential in wind farm energy capture optimization. However, a major limitation of previous work is the slow convergence, for which a primary cause is the low dither frequencies used by upwind turbines, primarily due to wake propagation delay through the turbine array. In this study, NLESC is enhanced with the predictor based delay compensation proposed by Oliveira and Krstic [1], which allows the use of higher dither frequencies for upwind turbines. The convergence speed can thus be improved, increasing the energy capture consequently. Simulation study is performed for a cascaded three-turbine array using the SimWindFarm platform. Simulation results show the improved energy capture of the wind turbine array under smooth and turbulent wind conditions, even up to 10% turbulence intensity. The impact of the proposed optimization methods on the fatigue loads of wind turbine structures is also evaluated.

Using Extremum Seeking Control to Improve the Power Capture of Midsize Hydrostatic Wind Turbines

2021 ◽  
Author(s):  
Daniel Escobar-Naranjo ◽  
Biswaranjan Mohanty ◽  
Kim A. Stelson
Keyword(s):  
Adaptive Control ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Control Strategies ◽  
Torque Control ◽  
Extremum Seeking ◽  
Extremum Seeking Control ◽  
Model Free ◽  
Point Tracking ◽  
Power Capture

Abstract Adaptive control strategies are commonly used for systems that change over time, such as wind turbines. Extremum Seeking Control (ESC) is a model-free real-time adaptive control strategy commonly used in conventional gearbox wind turbines for Maximum Power Point Tracking (MPPT). ESC optimizes the rotor power by constantly tuning the torque control gain (k) when operating below rated power. The same concept can be applied for hydrostatic wind turbines. This paper studies the use of ESC for a 60-kW hydrostatic wind turbine. First, a systematic approach to establish the ideal ESC is shown. Second, a comparison of the power capture performance of ESC versus the conventional torque control law (the kω2 law) is shown. The simulations include a timesharing power capture coefficient (Cp) to clearly show the advantages of using ESC. Studies under steady and realistic wind conditions show the main advantages of using ESC for a hydrostatic wind turbine.

Optimizing Energy Capture of Cascaded Wind Turbine Array With Nested-Loop Extremum Seeking Control

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Zhongzhou Yang ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Simulation Study ◽  
Wind Farm ◽  
Extremum Seeking ◽  
Power Coefficient ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Principle Of Optimality ◽  
Nested Loop

This paper proposes a nested-loop extremum seeking control (NLESC) scheme for optimizing the energy capture of wind farm that is formed by a wind turbine array along the prevailing wind direction. It has been shown in earlier work that the axial induction factors of individual wind turbines can be optimized from downstream to upstream units in a sequential manner, which is a spatial domain analogy to the principle of optimality in dynamic programing. Therefore, it is proposed to optimize the turbine operation by a nested-loop optimization framework from the downstream to upstream turbines, based on feedback of the power of the immediate turbine and its downstream units. The extremum seeking control (ESC) based on dither–demodulation scheme is selected as a model-free real-time optimization solution for the individual loops. First, the principle of optimality for optimizing wind farm energy capture is proved for the cascaded wind turbine array based on the disk model. Analysis shows that the optimal torque gain of each turbine in a cascade of turbines is invariant with wind speed if the wind direction does not change. Then, the NLESC scheme is proposed, with the array power coefficient selected as the performance index to be optimized in real-time. As changes of upstream turbine operation affect downstream turbines with significant delays due to wind propagation, a cross-covariance based delay estimate is used to improve the determination of the array power coefficient. The proposed scheme is evaluated with simulation study using a three-turbine wind farm with the simwindfarm simulation platform. Simulation study is performed under both smooth and turbulent winds, and the results indicate the convergence to the actual optimum. Also, simulation under different wind speeds supports the earlier analysis results that the optimal torque gains of the cascaded turbines are invariant to wind speed.

Maximizing Wind Turbine Energy Capture Using Multivariable Extremum Seeking Control

2009 ◽  
Vol 33 (4) ◽  
pp. 361-387 ◽  
Author(s):  
Justin Creaby ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Turbine ◽  
Extremum Seeking ◽  
Extremum Seeking Control ◽  
Energy Capture

Maximum Power Point Tracking of Proton Exchange Membrane Fuel Cell With Fractional Order Filter and Extremum Seeking Control

2015 ◽  
Author(s):  
Jianxin Liu ◽  
Tiebiao Zhao ◽  
YangQuan Chen
Keyword(s):  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Extremum Seeking ◽  
Maximum Power Point ◽  
Pass Filter ◽  
Extremum Seeking Control ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Exchange Membrane

Proton Exchange Membrane FC (PEMFC) is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking (MPPT) is one of the most important working conditions to be considered. In order to improve the searching performance such as convergence and robustness under disturbance and uncertainty, a kind of fractional order low pass filter (FOLPF) is applied for the MPPT controller design based on general Extremum Seeking Control (ESC). The controller is designed with FOLPF and high pass filter (HPF) substituting the normal LPF and HPF in the original ESC design. With this FOLPF ESC, better convergence and smooth performance is gained while maintaining the robust specifications. Simulation results are included to validate the proposed new FOLPF ESC scheme under disturbance and comparisons between FOLPF ESC and general ESC method are also provided.

Methods for Increasing Region 2 Power Capture on a Variable-Speed Wind Turbine

2004 ◽  
Vol 126 (4) ◽  
pp. 1092-1100 ◽  
Author(s):  
Kathryn E. Johnson ◽  
Lee J. Fingersh ◽  
Mark J. Balas ◽  
Lucy Y. Pao
Keyword(s):  
Wind Turbine ◽  
Maximum Energy ◽  
Control Methods ◽  
Variable Speed ◽  
Rotor Speed ◽  
Energy Capture ◽  
Control Scheme ◽  
Variable Speed Wind Turbine ◽  
Power Capture ◽  
Speed Fluctuations

The standard region 2 control scheme for a variable-speed wind turbine, τc=Kω2, has several shortcomings that can result in significant power loss. The first of these is that there is no accurate way to determine the gain K; modeling programs are not accurate enough to represent all of the complex aerodynamics, and these aerodynamics change over time. Furthermore, it is not certain whether the value of K used in the standard control even provides for the maximum energy capture under real-world turbulent conditions. We introduce new control methods to address these issues. First, we show in simulation that using smaller values of K than the standard can result in increased energy capture. Second, we give simulation results showing that an optimally tracking rotor control scheme can improve upon the standard scheme by assisting the rotor speed in tracking wind-speed fluctuations more rapidly. Finally, we propose an adaptive control scheme that allows for maximum power capture despite parameter uncertainty.

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