Power-setpoint extremum seeking control for maximizing wind power capture of turbine and farm operation

2020 ◽  
pp. 0309524X2097991
Author(s):  
Devesh Kumar ◽  
Yaoyu Li ◽  
Zhongyou Wu
Keyword(s):  
Control Strategy ◽  
Extremum Seeking ◽  
Power Demand ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Model Free ◽  
Free Region ◽  
Power Capture ◽  
Back Calculation ◽  
Nested Loop

In this paper, we propose a power-setpoint based Extremum Seeking Control (ESC) framework for model-free Region-2 controls for maximizing the power capture for turbine and farm operation, without dependency on wind measurement. As a major obstacle for retrofitting wind turbine/farm controls is that only the power setpoint is accessible, the power-setpoint based ESC framework is proposed with a back-calculation anti-windup structure. If increasing the power demand cannot further increase actual power output, the anti-windup structure automatically holds the power demand setpoint. For farm operation, the proposed method is integrated into the Delay-compensated Nested-loop ESC. The proposed method is evaluated by simulations on the SimWindFarm platform for both single-turbine and farm operation scenarios. The results demonstrate the capability of tracking the achievable optimum power for turbine and farm operation, with only reasonable increase of some loads. The proposed method promises an easy-to-implement model-free retrofitting control strategy for enhancing wind energy capture.

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 Farm Energy Capture via Nested-Loop Extremum Seeking Control

2013 ◽  
Author(s):  
Zhongzhou Yang ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Farm ◽  
Extremum Seeking ◽  
Variable Speed ◽  
Extremum Seeking Control ◽  
Control Approach ◽  
Energy Capture ◽  
Cross Covariance ◽  
Scheme Analysis ◽  
Loop Scheme ◽  
Nested Loop

This paper proposes a novel control approach for optimizing wind farm energy capture with a nested-loop scheme of extremum seeking control (ESC). Similar to Bellman’s Principle of Optimality, 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, i.e. the turbine operation can be optimized based on the power of the immediate turbine and its downstream units. In this study, this scheme is illustrated for wind turbine array with variable-speed turbines for which torque gain is controlled to vary axial induction factors. The proposed nested-loop ESC is demonstrated with a 3-turbine wind farm using the SimWindFarm simulation platform. Simulation under smooth and turbulent winds show the effectiveness of the proposed scheme. 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, which is supported by simulation results for smooth wind inputs. As changes of upstream turbine operation affects the downstream turbines with significant delays due to wind propagation, a cross-covariance based delay estimate is proposed as adaptive phase compensation between the dither and demodulation signals.

scholarly journals Model-Free Extremum Seeking Control of Bioprocesses: A Review with a Worked Example

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1209
Author(s):  
Laurent Dewasme ◽  
Alain Vande Wouwer
Keyword(s):  
Dynamic Models ◽  
Operating Conditions ◽  
Extremum Seeking ◽  
Usual Practice ◽  
Extremum Seeking Control ◽  
Model Free ◽  
Worked Example ◽  
Current Trends ◽  
Simple Simulation ◽  
Recent Developments

Uncertainty is a common feature of biological systems, and model-free extremum-seeking control has proved a relevant approach to avoid the typical problems related to model-based optimization, e.g., time- and resource-consuming derivation and identification of dynamic models, and lack of robustness of optimal control. In this article, a review of the past and current trends in model-free extremum seeking is proposed with an emphasis on finding optimal operating conditions of bioprocesses. This review is illustrated with a simple simulation case study which allows a comparative evaluation of a few selected methods. Finally, some experimental case studies are discussed. As usual, practice lags behind theory, but recent developments confirm the applicability of the approach at the laboratory scale and are encouraging a transfer to industrial scale.

scholarly journals Extremum Seeking Control for Model-Free Auto-Tuning of Powered Prosthetic Legs

2020 ◽  
Vol 28 (6) ◽  
pp. 2120-2135 ◽  
Author(s):  
Saurav Kumar ◽  
Alireza Mohammadi ◽  
David Quintero ◽  
Siavash Rezazadeh ◽  
Nicholas Gans ◽  
...  
Keyword(s):  
Extremum Seeking ◽  
Extremum Seeking Control ◽  
Model Free ◽  
Auto Tuning

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.

Assessment of Extremum Seeking Control for Wind Farm Energy Production

2012 ◽  
Vol 36 (6) ◽  
pp. 701-715 ◽  
Author(s):  
Kathryn E. Johnson ◽  
Geraldine Fritsch
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Extremum Seeking ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Time Varying Delay ◽  
Aerodynamic Interaction ◽  
Control Research ◽  
High Turbulence ◽  
Wind Input

Aerodynamic interaction among turbines grouped together in wind farms causes a decrease in the total energy extracted from the wind when compared to an equal number of widely dispersed turbines operating under the same wind input conditions as the wind farm. Extremum seeking control (ESC) is one strategy that holds promise for reducing this impact under certain wind input conditions. In this paper, we evaluate the effectiveness of ESC under different turbulence conditions, describing methods for addressing the complexities caused by the turbulent wind input and time-varying delay of the wind between turbines, where these two elements are the most important contributions compared to other wind farm control research. The results show that energy capture can be increased in low turbulence intensity conditions, but perhaps not in high turbulence conditions.

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