Torque and blade pitch control of variable speed variable pitch wind turbines

In this thesis, aerodynamic torque control of isolated distribution network wind turbines is accomplished by adjusting pitch angle. The changeable parameter of aerodynamic power value after the desing of wind turbine is performance coefficient for variable-pitch wind turbines. Performance coefficient can be adjusted by turning blades around itself at vertical axes. By modifying blade pitch, maximum available wind energy can be obtained and variations in power can be reduced. Thus, output power oscillation and stresses of mechanical structure in high speed can be also reduced. Pitch actuators is used for the adjusting of pitch angle. Pitch actuators have hidrolic or electrical structure in many applications.In this study, two different pitch actuators model is used in order to provide blade movement. These are pitch actuator as integrator with saturation and pitch actuator with three levels of pitching speed. After all using of the pitch acuator with three levels of pitching speed reduce the duration of blade movement but this will produce much more power oscillations than the pitch actuator as integrator with saturation. The PI controller has been used for pitch angle control and the models has been made up in the Matlab/ Simulink simulation enviroment.