Analysis and multi-objective optimisation of wind turbine torque control strategies

<p>The combined wind speed estimator and tip-speed ratio (WSE–TSR) tracking wind turbine control scheme has seen recent and increased traction from the wind industry. The modern control scheme provides a flexible trade-off between power and load objectives. On the other hand, the <span clas...

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Bibliographic Details
Main Authors: L. Brandetti, S. P. Mulders, Y. Liu, S. Watson, J.-W. van Wingerden
Format: Article
Language:English
Published: Copernicus Publications 2023-10-01
Series:Wind Energy Science
Online Access:https://wes.copernicus.org/articles/8/1553/2023/wes-8-1553-2023.pdf
Description
Summary:<p>The combined wind speed estimator and tip-speed ratio (WSE–TSR) tracking wind turbine control scheme has seen recent and increased traction from the wind industry. The modern control scheme provides a flexible trade-off between power and load objectives. On the other hand, the <span class="inline-formula"><i>K</i><i>ω</i><sup>2</sup></span> controller is often used based on its simplicity and steady-state optimality and is taken as a baseline here. This paper investigates the potential benefits of the WSE–TSR tracking controller compared to the baseline by analysis through a frequency-domain framework and by optimal calibration through a systematic procedure. A multi-objective optimisation problem is formulated for calibration with the conflicting objectives of power maximisation and torque fluctuation minimisation. The optimisation problem is solved by approximating the Pareto front based on the set of optimal solutions found by an explorative search. The Pareto fronts were obtained by mid-fidelity simulations with the National Renewable Energy Laboratory (NREL) 5 MW turbine under turbulent wind conditions for calibration of the baseline and for increasing fidelities of the WSE–TSR tracking controller. Optimisation results show that the WSE–TSR tracking controller does not provide further benefits in energy capture compared to the baseline <span class="inline-formula"><i>K</i><i>ω</i><sup>2</sup></span> controller. There is, however, a trade-off in torque control variance and power capture with control bandwidth. By lowering the bandwidth at the expense of generated power of 2 %, the torque actuation effort reduces by 80 % with respect to the optimal calibration corresponding to the highest control bandwidth.</p>
ISSN:2366-7443
2366-7451