Investigation into reduction of the Cost-Of-Energy of the Upwind 5.0 MW Wind Turbine using Higher- Harmonic Individual Pitch Control

Individual Pitch Control has been a topic of study in the field of wind turbine engineering for more than a decade. It has been shown that a load reducing controller can be designed that makes use blade root moment measurements. Various authors have performed simulations to estimate the extent to which Individual Pitch Control can reduce fatigue damage for rotating components. More recently, the application of IPC to reduce fatigue damage of fixed frame components has been investigated. One effective method is to extend the IPC algorithm to harmonics of the rotor frequency. While the effectiveness of IPC control is acknowledged by many authors, there has been little published on how to use the fatigue reductions to reduce the cost-of-energy for a wind turbine. In this thesis, an attempt is made to formulate a design methodology for higher harmonic IPC, to capitalize on the fatigue reductions by making design changes to the turbine, and finally estimating the potential profit of these changes. The wind turbine model used in this work is the Upwind 5.0 MW onshore conceptual wind turbine. It was implemented into the aeroelastic wind turbine simulation software FAST. The software of FAST was interfaced with the software package of Simulink which allows for intuitive control design. A combination of Linear Time Invariant control design, and time-marching simulation analyses was used to optimize the various controllers used in the simulations. The reductions of fatigue obtained for the baseline turbine, were around 18% for the blade root flapwise bending moment, and 15% for the analysed moments of the fixed frame components. Based on the fatigue reductions obtained through the controller implementation, three redesign cases were formulated: - Upscaling of the rotor diameter - Reducing the weight of the rotor blades - Increasing the power rating of the turbine Simulations of the redesigned turbines were performed to see if the redesigns were viable. For the cases which were considered viable, the upscaling and weight reduction case, a cost analysis was performed. This cost analysis provided an estimated 1.6 million $ added profit over the turbine lifetime for the rotor upscaling case, and an estimated -130,000 $ loss for the weight reduction case.Aerospace EngineeringDuWin