چكيده به لاتين
In this thesis, a Hybrid controller designed for wind turbine in operating conditions for two
main operation region of wind turbine. Wind turbine is a complex nonlinear system involving diffrenet operation regions that its operation region changes depending on environmental and physical conditions but generally two main operation region are considered for wind turbine that control objective in each region is different. In this thesis, wind turbine control is performed in two regions this means that in first region in order to catch maximum power extraction, generator speed control is employed and in second region pitch angle control is used to keeping output generator power at constant rated value.
In wind turbines, wind in addition to act as a driving force is a disturbance factor because of its random nature .The pitch control system is one of the most widely used control techniques to regulate output power of a wind turbine that involved fluctuations. The mathematical model of the system should be well known to control the pitch angle by the conventional PID controller. on the other hand ,Tuning parameters of this controller are not consistently changed. For control the speed of the generator also use of PID controller has some problems.So to cope with the nonlinear characteristics of wind turbine also to deal with the disturbances and uncertain factors in both operating regions an adaptive controller is required. Fuzzy controller have advantages like adaptation and robustness and don't need to any accurate mathematical model but the accuracy of PID controller can not be ignored in reducing the steady-state error. Hence in this thesis a hybrid controller is designed that combined adaptive fuzzy controller with PID controller. During the early period the fuzzy controller is being used to improve system responsiveness and reduce the overshoot .When entering to steady-state regulation period, PID controller is being used to keep the the steadystate error at minimum value. Since sudden changes in wind speed may have undesirable effects on the mechanical blade and system performance so the controller designed in this thesis is investigated in the presence of disturbances in wind speed simulation model based on Kamal's spectrum. After simulation of adaptive hybrid controller designed for a 0.9 MW wind turbine and discussion about its results in normal condition and in the presence of disturbance, a comparision between proposed adaptive hybrid controller and conventional PID controller is performed. The simulation results show that the adaptive hybrid controller can achive better control performances in both operating regions than conventional PID controllers.
Key words: Wind turbines, Pitch control, Hybrid controller, Adaptive fuzzy controller,
Reduce disturbance effect
