Effects of Inflow Conditions on Aerodynamic Transient Characteristics with Pitch Control of Horizontal Axis Wind Turbine

Abstract

The control of the wind turbine rotor aims to increase the turbine output and to reduce the fluctuations of the output and the structural load. The change in the operating condition, such as the blade pitch control, causes the aerodynamic transient of the rotor, which affects the fluctuations of the output and/or the structural load. The yaw misalignment of the rotor axis to the inflow wind direction often occurs in the natural wind condition. When the wind flows diagonally to the rotor, the angle of attack of the blade relative to inflow wind speed changes during a rotation of the blade, which occurs the fluctuation of the torque and the structural load. The present study examines the aerodynamic transient characteristics of the rotor due to the blade pitch control, for the horizontal axis wind turbines for values of the tip speed ratio and the yaw misalignment.