Reducing tower fatigue through blade back twist and active pitch-to-stall control strategy, for a semi-submersible floating offshore wind turbine

Dawn Ward, Maurizio Collu, Joy Sumner

Research output: Contribution to journalArticle

Abstract

The necessity of producing more electricity from renewable sources has been driven predominantly by the need to prevent irreversible climate chance. Currently, industry is looking towards floating offshore wind turbine solutions to form part of their future renewable portfolio. However, wind turbine loads are often increased when mounted on a floating rather than fixed platform. Negative damping must also be avoided to prevent tower oscillations. By presenting a turbine actively pitching-to-stall, the impact on the tower fore–aft bending moment of a blade with back twist towards feather as it approaches the tip was explored, utilizing the time domain FAST v8 simulation tool. The turbine was coupled to a floating semisubmersible platform, as this type of floater suffers from increased fore–aft oscillations of the tower, and therefore could benefit from this alternative control approach. Correlation between the responses of the blade’s flapwise bending moment and the tower base’s fore–aft moment was observed with this back-twisted pitch-to-stall blade. Negative damping was also avoided by utilizing a pitch-to-stall control strategy. At 13 and 18 m/s mean turbulent winds, a 20% and 5.8% increase in the tower axial fatigue life was achieved, respectively. Overall, it was shown that the proposed approach seems to be effective in diminishing detrimental oscillations of the power output and in enhancing the tower axial fatigue life.
LanguageEnglish
Article number1897
Number of pages16
JournalEnergies
Volume12
Issue number10
DOIs
Publication statusPublished - 18 May 2019

Fingerprint

Offshore wind turbines
Wind Turbine
Blade
Twist
Fatigue
Towers
Control Strategy
Fatigue Life
Fatigue of materials
Turbine
Oscillation
Moment
Damping
Diminishing
Bending moments
Simulation Tool
Electricity
Climate
Time Domain
Turbines

Keywords

  • floating offshore wind turbine (FOWT)
  • pitch-to-stall
  • blade black twist
  • tower fore–aft moments
  • negative damping
  • blade flapwise moment
  • tower axial fatigue life

Cite this

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title = "Reducing tower fatigue through blade back twist and active pitch-to-stall control strategy, for a semi-submersible floating offshore wind turbine",
abstract = "The necessity of producing more electricity from renewable sources has been driven predominantly by the need to prevent irreversible climate chance. Currently, industry is looking towards floating offshore wind turbine solutions to form part of their future renewable portfolio. However, wind turbine loads are often increased when mounted on a floating rather than fixed platform. Negative damping must also be avoided to prevent tower oscillations. By presenting a turbine actively pitching-to-stall, the impact on the tower fore–aft bending moment of a blade with back twist towards feather as it approaches the tip was explored, utilizing the time domain FAST v8 simulation tool. The turbine was coupled to a floating semisubmersible platform, as this type of floater suffers from increased fore–aft oscillations of the tower, and therefore could benefit from this alternative control approach. Correlation between the responses of the blade’s flapwise bending moment and the tower base’s fore–aft moment was observed with this back-twisted pitch-to-stall blade. Negative damping was also avoided by utilizing a pitch-to-stall control strategy. At 13 and 18 m/s mean turbulent winds, a 20{\%} and 5.8{\%} increase in the tower axial fatigue life was achieved, respectively. Overall, it was shown that the proposed approach seems to be effective in diminishing detrimental oscillations of the power output and in enhancing the tower axial fatigue life.",
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Reducing tower fatigue through blade back twist and active pitch-to-stall control strategy, for a semi-submersible floating offshore wind turbine. / Ward, Dawn; Collu, Maurizio; Sumner, Joy.

In: Energies, Vol. 12, No. 10, 1897, 18.05.2019.

Research output: Contribution to journalArticle

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