Study On The Hydraulic Pitch System Of Wind Turbine

Wind energy is widespread in nature,with renewable,pollution-free advantages,people have learned to use wind energy for a long time.With the rapid development of human science and technology,energy shortage,environmental pollution and other problems are increasingly prominent.Wind power generation has gradually attracted wide attention due to its low cost,high generating capacity and friendly to the environment.Hydraulic system with its high specific power density,easy to operate and control,easy to achieve automation and other advantages,applied in the megawatt wind turbine,to provide the driving force for the brake system,yaw system and the rotor system.Since the generator in a large wind turbine can't control the output power independently,the variable pitch control technology is often needed to stabilize the output power.According to the requirements of the current wind speed and power output,the rotor pitch Angle can be adjusted in real time to control the impeller speed to reach the grid speed of the generator for power generation.According to the different driving mode of the variable propeller is divided into hydraulic drive variable propeller and motor drive variable propeller.The hydraulic system and the propeller system,especially the actuator of the propeller,are prone to failure due to the variable stress and over load operation.This paper takes the hydraulic variable-blade system of wind turbine as the research object,and studies it from the aspects of operation theory,composition of hydraulic system,control mode of variable-blade system,common faults and treatment methods,including:1.based on the basic operating theory and operating conditions of wind turbine,the principle of variable pitch control is analyzed;2.the typical power regulation mode and variable pitch control mode of wind turbine are introduced,and the force borne by the impeller system and the fatigue life of the actuator under different operating conditions are analyzed;3.according to the working characteristics of the paddle changing system and the combination of PID control and fuzzy logic reasoning system,the fuzzy PID control method applicable to the paddle changing system is proposed;4.this paper focuses on the study of the causes and treatment methods of common faults in the hydraulic variable paddle system of wind turbine units,finds out the weak links in the system design,carries out technical transformation and verifies the transformation effect,thus providing an effective fault treatment scheme for the hydraulic variable paddle system of wind turbine units.