Improved linearised models of wind turbine aerodynamics and control system dynamics using harmonic linearisation
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Publication Date
2019-05Journal Title
Renewable Energy
ISSN
0960-1481
Publisher
Elsevier BV
Volume
135
Pages
148-162
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Lupton, R., & Langley, R. (2019). Improved linearised models of wind turbine aerodynamics and control system dynamics using harmonic linearisation. Renewable Energy, 135 148-162. https://doi.org/10.1016/j.renene.2018.11.067
Abstract
Where non-linearities are not too strong, linearised frequency-domain approaches offer fast calculations, which can be valuable for preliminary design of wind turbine blades, foundations and floating platforms. But the aerodynamic and control system behaviour of a wind turbine is noticeably non-linear. Here we show for the first time that the technique of harmonic linearisation can reduce error in the approximation of aerodynamic and control system non-linearities, compared to the more common tangent linearisation. After deriving the linearised models, comparing linearised results to non-linear simulations for the NREL 5MW turbine shows that: (1) harmonic linearisation captures aero-elastic effects and non-linearity in aerodynamic forces, giving a 2–4x reduction in error compared to the tangent linearisation; (2) harmonic linearisation can capture non-linear wake dynamics; and (3) the torque and pitch controller behaviour can be approximated with good results away from the rated wind speed but with some challenges when the two controllers interact. Further improvements in the linearised model of the control system have been identified. By improving the accuracy of linearised models, harmonic linearisation is a promising means to extend the applicability of frequency-domain approaches for initial design and optimisation of wind turbines.
Sponsorship
This work was funded by an EPSRC doctoral training award (ref. 1089390)
and supported by GL Garrad Hassan.
Funder references
EPSRC (1089390)
Identifiers
External DOI: https://doi.org/10.1016/j.renene.2018.11.067
This record's URL: https://www.repository.cam.ac.uk/handle/1810/287228
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc-nd/4.0/
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