| Popis: |
The smart rotor is an upgrade to the wind turbine rotor that facilitates active modification of the blade aerodynamics, thus allowing enhanced control of the rotor loads. In this thesis a number of research areas relating to the smart rotor are explored and advanced. The synthesised wind field spatial and temporal requirements are assessed, suggesting the current guidelines, of less than 5m spatial and 10Hz temporal resolutions, are more than adequate. Also regarding the wind field, it is shown that the smart rotor provides the greatest percentage benefits when there is high wind shear, but low turbulence intensity. An analytical approach to selecting the chord-width of trailing edge flaps, based on thin aerofoil theory, is presented. Demonstrating a trade-off between flap size, flap actuator requirements and load reductions. The unsteady aerodynamics of trailing edge flaps and their modelling in Bladed is also considered, showing only a limited requirement to develop the aerodynamic code. A comparison of individual pitch and smart rotor controllers shows that both methods can achieve similar load reductions. The main benefit of using a smart rotor system is the lower pitch motion. The smart rotor is also shown to reduce pitch motion by supplementing collective pitch control. The trade between pitch actuator requirements, load reductions and the cost of smart rotor control, is therefore considered the defining factor in valuing the smart rotor, rather than purely load reductions. Finally, a fault scenario of a single jammed flap is detected and corrected for. With results suggesting that even unreliable systems can achieve a significant lifetime fatigue load reduction. These studies are conducted using a methodical process detailed in this thesis, such that future researchers may build upon this work. Access to the models and code developed are provided in the appendix. |
