Research On Control Technology Of Hydraulic Pitch Of Wind Turbine Generator

In the development of wind power industry,the low wind speed are and region are the two hot research.Consequently,the wind turbine blade is longer,the load of the blade root is larger,and the required pitch driving torque is also increased.The traditional single motor driving single blade electric propeller has been difficult to meet the requirements.The hydraulic variable pitch system has the characteristics of simple structure,high thrust,wide frequency band and so on,which are more and more advantageous in the application of the low wind speed region and the larger capacity off-shore wind turbine.There are many problems existing in the wind power generator,such as hysteresis,power fluctuation and anti-interference.To make the hydraulic variable pitch wind turbine has better performance,based on the control theory of wind turbine and the principle of pitch angle adjustment,researching on hydraulic variable pitch wind turbine,the main contents are as follows:(1)The comparative analysis of the hydraulic and electric propeller mechanism shows that the hydraulic propeller system have competitive advantages of large capacity wind turbinein in low wind speed region and sea.Through the analysis and calculation of the blade,the driving force of the blade rotation is obtained.(2)Establishing the mathematical model and the physical model of the hydraulic system and simulated.The results show that the process of open pitch and closed pitch of the mathematical model to achieve the optimal results,which require different PI values;building the physical model under the control of PI,which can finish open and close pitch function of hydraulic variable pitch system,noise disturbance signal reduces the control accuracy of hydraulic variable pitch propeller system.(3)In order to further study the performance of hydraulic pitch control system,according to the composition of the wind turbine,the hydraulic variable pitch wind turbine system model is constructed and simulated,the results show that the wind energy utilization rate is insufficient when hydraulic variable pitch wind turbine run below the rated wind speed,fluctuation of wind wheel speed and power when above the rated wind speed,and anti-noise interference ability is not enough.(4)According to insufficient control accuracy of the hydraulic variable pitch sysyem and low utilization rate of wind energy power of hydraulic variable pitch wind turbine,power fluctuation and lack of anti interference ability,fuzzy PI controller and unscented Kalman filter are designed,hydraulic pitch control system and hydraulic variable pitch wind turbine are simulated,the results show that the response time of hydraulic variable the pitch system is reduced,the control precision is increased;the utilization coefficient of hydraulic variable pitch wind turbine to meet the design value,the wind wheel speed is stable,power is stable,anti noise ability is enhanced.