The Research Of Variable Pitch Hydraulic Control System Of Wind Turbine

Compared wind energy with fossil-fuel energy and nuclear energy, the former has a lower development cost, safty, clean environment, renewable, etc. Wind energy is paid more and more attention around the world because of it is a kind of renewable clean energy. Currently large input power wind turbines utilize VSCF (Variable speed contant frequency) technology in variable pitch hydraulic system of wind turbine in order to improve speed of response, get maximum power when lower wind speed, get rated power when higher wind speed.First of all, the thesis reviews the current situation and development trend of domestic and foreign wind turbine. It elaborates the purpose and significance. It introduces the component and the operating principle of wind turbine and characteristics of unvariable and variable pitch wind turbine. We make aerodynamics analysis of variable pitch system clearly based on Betz theory. We deduce wind energy utilization coefficient and define the connection between wind energy utilization coefficient and angle of pitch. It supply theoretical basis for defining control strategy of variable pitch hydraulic system of wind turbine.Secondly, we calculate driving force of variable pitch, carrying of hydraulic system, system flow and heat of hydraulic system and design the variable pitch hydraulic system of wind turbine. We choose the type of hydraulic elements sensibly and optimize the layout of hydraulic station with thinking about internal volume of wind turbine limited. And then, we analize the operating principle of hydraulic system and the hydraulic circuit detailed. We also draw the three dimensions of hydraulic station of variable pitch hydraulic system.Finally, since the hydraulic circuits during opening pitch and closing pitch are different, we use transfer function method to build model of opening pitch and closing pitch. We carry out simulation based on MATLAB-Simulink and Automation Studio. PID controller and fuzzy adaptive PID controller has been in the model in order improve the characteristic of dynamic response.