August 1, 2012.
Wind turbines generate electric power from clean renewable sources. They must be robust and reliable. Utility-scale turbines are designed to produce power within a set of wind speed parameters. When winds change, wind turbine blade pitch is used to protect the turbine from over speed damage.
Advanced control algorithms can increase power by extending the performance envelope or they can extend lifetime by reducing stress. A FAST simulation written in MATLAB / Simulink is used to simulate the dynamics of the integrated aerodynamic, mechanical and control subsystems of the turbine. Resonance modes may lead to large amplitude displacements and damage. The goal of the control system is to limit these excursions.
We use simulation for parametric studies of the factors causing blade flex and, ultimately, degradation. Wind speed and its variation over time is one factor. We also study the effect of damage to a turbine blade by increasing the elasticity at a boundary between the modeled rigid segments of the blade structure. We compare a baseline controller with an adaptive controller. We also examine tradeoffs in control strategies that permit safe, but degraded, energy capture despite limited blade damage.
NASA Ames Research Center (ARC)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).