Study On Electro-hydraulic Pitch-control System For Wind Turbine

The urgent problems that need to be resolved for today's human existence and development are energy and environment.Wind power is paid more attention by more and more countries as renewable and pollution-free energy resource.It is different from the conventional energy resources which are limited and also cause serious air pollution.Variable-pitch system as one of the core of the large-scale wind turbine is important for the unit's security,stability and efficient operation.Therefore, the study on Pitch-control System for Wind Turbine has a great meaning.Firstly,this paper analyzed the dynamic characteristics of wind turbine based on the Betz Wind Turbine Theory and Blade Element Momentum Analysis Theory; proposed the definition and characteristics of the wind energy utilization coefficient C_p,explained the variable-pitch control principle of wind turbine in theory, described the variable-pitch control system block diagram and the control process.Secondly,analyzed the kinematics and mechanical of variable-pitch mechanism, built the virtual pitch-controlled wind turbine model by Pro/E,and the model is emulated in ADAMS environment to analyze the dynamic characteristics of it.Thirdly,basing on the character of the hydraulic system of the turbine,the linear mathematical models of the system are built up respectively in the course of pitch-increase and pitch-decrease of the turbine;designed a fuzzy PID controller used in variable-pitch system based on conventional PID control and fuzzy control principle,and the models are respectively simulated in MATLAB/SIMULINK in PID control algorithm and fuzzy PID control algorithm.At last,the electro-hydraulic serve test system for variable-pitch wind turbine is established based on the variable-pitch principle.The real time control software and operation flat form is edited by using the LabVIEW.The hydraulic variable-pitch control experiment is operating on the hydraulic serve test system based on fuzzy PID control.The result is consistent with the simulation test. Experimental results show that in variable-pitch control using the fuzzy PID control strategy is better than PID control,has a good static and dynamic characteristics and a certain degree of adaptability,can effectively control the pitch-angle of the wind turbine and providing a theoretical support in variable-pitch control.