Large-scale Wind Turbine Individual Pitch Control Technology Research

Now, the environment problem has become a growing concern worldwide, as the pollution of the environment is becoming increasingly serious, these force people to search for other types of energy, our country will take vigorous action to develop renewable energy. China devote major efforts to develop renewable energy, scholars worldwide are competitive researching wind power technology. Because the tendency of wind power development is large-scale wind turbine and developing offshore wind power, these caused the mainstream model is individual pitch wind turbine, and the correspondence difficulty and key is individual pitch control technology, to reduce the imbalanced load of blades and steady output power. In this paper, 3MW double-feed variable speed pitch regulated wind turbine is studied, collective pitches systems and individual pitches systems are designed, and mathematical models are built in MATLAB, so that we can test the reasonable and the perfect control effect through simulation.Firstly, variable pitch control process is studied after analyzing the aerodynamic theory about wind turbine, built mathematical models for each unit of wind turbine, design collective pitch controller and PID controller, implies the feasibility of this method from simulation, and then realize variable pitch control of wind turbine.Secondly, In order to decrease the fatigue of units caused by imbalance loads, we have to design a scheme of individual pitch control. Control blades individually base on the weight coefficients of blade azimuth angles. According to the effect that tilt angle makes on forces, regulate weight coefficient according to tilt angles, to change attack angle and make further improvement on forces. The simulation cooperation between this new method and the conventional individual pitch control method can verify the feasibility of the control system, and is more suitable for large-scale wind turbine pitch control.Again, because of the great nonlinearity of variable pitch wind turbine, the effect of traditional PID control is not very perfect. So this paper proposes Three-Dimension Fuzzy PID power control scheme, to improve the accuracy of power control. An objective-based dynamic weighting fuzzy control model is presented considering to the forces of the blades, improved the overall response speed and performance of the variable pitch system composed of power control system and blade forces control system.