| Wind power,in the growing energy shortages and environmental pollution today, not only can use the inexhaustible characteristics of wind power to replace the conventional energy in order to alleviate the energy crisis,but also reduce environmental pollution,so it can bring directly economical and environmental benefits to society.This subject comes from scientific and technological project of Lanzhou: "The detection and monitoring of feedback control equipment about large-scale wind turbine(Item Number:2008-1-16)".This paper describes the related basic theory about large-scale wind turbine, establishes the wind mathematical models based on the characteristics of random changes in wind speed and wind direction;It is important that the wind turbine's detection of feedback control system to achieve the standard of coupling and give full play of wind turbine performance, through establishing the model about the wind turbine flexible transmission system and simulating the Open-loop system between wind characteristics and wind turbine dynamic characteristics.When the wind speed and direction changes,the original maintained coupling relationship between wind characteristics and dynamic characteristics of wind turbine is destroyed.Then the controller adjust the blade pitch angle(pitch control)or the yaw angle(yaw control) selectively through receiving the output feedback signal,so that the wind machine's output power or speed is always maintained to the standard of coupling,and achieve the coupling between wind characteristics and dynamic characteristics of wind turbine.Based on the coupling of wihd and wind turbine dynamic characteristics,this paper proposed the method about wind turbine's pitch control when it is in the wind above the rated speed.If wind turbine's output power and the speed are constant,then the generator's torque and speed are also constant when through the transmission,that can achieve a constant about output power.Proposed the method of exact feedback linearization based on the nonlinear wind turbine model,designed the nonlinear optimal controller.Built the simulation model in Matlab/Simulink and verify that the nonlinear controller enables reach to the coupling of wind and wind turbine.The wind turbine's yaw can be divided into two parts:focus on the wind when it is low wind or deviate the wind when it is high wind.The key research is the section composite controller between fuzzy and PID when it is low wind. When the detection feedback gap is greater than a threshold, the fuzzy controller comes to work. Because fuzzy controller can make full use of dynamic performance and reduce the overshoot; On the contrary, PID controller comes to work because it can reduces steady-state gap. At last, the simulation checked the result of coupling between wind and wind turbine's dynamic characteristics. |
