Abstract
The problem of negative damping undermines the aeroservoelastic stability of floating offshore wind turbines. The negative damping problem is most prevalent around rated wind speed, where the sensitivity of thrust to wind speed is the largest. This paper investigates the implementation of peak shaving, a controller feature that limits the rated thrust by pitching the blades before rated wind speed is reached. Two controller designs are investigated: a de-tuned controller and a nacelle-feedback controller. A time-domain metric is defined, inspired by Lyapunov theory, in order to compute and assess the stability of floating offshore wind turbines. The model of the International Energy Agency 15-MW reference wind turbine mounted on the University of Maine VolturnUS-S floater is simulated in HAWC2 with the National Renewable Energy Laboratory reference open-source controller. Peak shaving is applied to the two controller designs and stability is assessed. According to the chosen metric, peak shaving does not improve the stability of the system. This is due to the trade-off between loads and error tracking: although the loads and displacements in the fore-aft direction of the turbine are reduced, the rotor-speed tracking is poorer, which increases the shaft torsion fatigue load.
Original language | American English |
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Article number | Article No. 042001 |
Number of pages | 9 |
Journal | Journal of Physics: Conference Series |
Volume | 2265 |
Issue number | 4 |
DOIs | |
State | Published - 2 Jun 2022 |
Event | 2022 Science of Making Torque from Wind, TORQUE 2022 - Delft, Netherlands Duration: 1 Jun 2022 → 3 Jun 2022 |
Bibliographical note
Publisher Copyright:© Published under licence by IOP Publishing Ltd.
NREL Publication Number
- NREL/JA-5000-82041
Keywords
- controls
- floating wind
- stability