Aerodynamic design of a micro wind turbine and performance analysis with QBlade

This thesis describes the process of designing a 0.84 m diameter and 125 W horizontal axis micro wind turbine. The study is focused not only on rotor aerodynamics but also on the selection of main components for power generation and control. For the purpose of this investigation, pitch and yaw control are not considered. In the first part, blade design and performance analysis are presented. Rotor size is selected as a trade-off between different constraints, including 3D printer limited capacity, low costs and relatively high power output. The small dimension of the blade enforces the adoption of a low Reynolds airfoil, selected among several profiles for its ability to guarantee higher lift to drag ratio. Blade shape optimisation, in terms of chord and twist, is performed with QBlade for different values of Tip Speed Ratio: influences of this parameter on power coefficient (Cp), power, torque and thrust are investigated. The ability of starting at low wind speeds was a crucial factor in the choice of the final blade design. Subsequently, generator requirements and its selection are discussed, as well for speed and torque sensors. Main Maximum Power Point Tracking (MPPT) control strategies and application of Optimal Torque control are then analysed. Lastly, some considerations are made on the possible conversion of this set up in a scaled wind turbine for experimental testing.