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Study On The Technology Of Pitch-control For Large Scale Wind Turbine

Posted on:2006-08-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y G LinFull Text:PDF
GTID:1102360155963244Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
Now with energy resources being consumed increasingly to be exhausted and environment empoison being serious gradually, wind power is paid great attention to by more and more countries as renewable resource and pollution-free energy resource. The technology also becomes research hotspot of many scholar.In the thesis, the variable-speed constant-frequency pitch-controlled theoretical basis is put forward by research of wind turbine aerodynamic characteristics and is proved rationally by model emulation. Based on the domestic element and process level, the electro-hydraulic proportional pitch-controlled actuator is designed according to the characteristics such as rapidity, energy conservation and security. The pitch-controlled wind turbine semi-physical simulation test-bed is formed, with the pitch-controlled actuator, load device and control being real and the other of the wind turbine being substituted by emulational models. The semi-physical simulation test-bed equals to the real pitch-control wind turbine. In the test-bed, the control performances are all satisfied the demands under the condition of starting up, lower the rate wind speed, above the rate wind speed, parking, normal stop, and emergency stop. Because of the great nonlinearity of wind turbine, the traditional PID control effect is not very perfect. The model predictive control is adapted for pitch control. Support vector regression algorithm is used for wind turbine nonlinear system identification to identify wind turbine nonlinear system. Because the differential circuit is used in the electro-hydraulic proportional pitch-controlled system, the model of feathering is different from that of backpaddling. Therefore the two models are switched in the predictive control course. Considering that torque impact has greatly effect on the life length of gearbox, the torque load limited constraint condition is added to predictive control. Then, when wind speed is up the rated speed, the generator power is kept more steadily around the rated and the pitch load fluctuation is greatly lower than that by adopting the traditional PID control.The individual pith control by electromotor is also another good power control method. The actuator is designed in the thesis. The control strategy is to combine fuzzy control with the weight number that is mainly decided by the acceleration and the blade azimuth angle. The simulation result indicates that when the wind speed is higher than the rated speed, the pitch load fluctuation is greatly reduced and the output power is kept around the rated speed.
Keywords/Search Tags:Pitch-Controlled, Wind Power Generation, Variable-Speed Constant-Frequency, Electro-Hydraulic Proportional, Support Vector Regression, Model Predictive Control, Weight Number
PDF Full Text Request
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