Research On Megawatt Wind Turbine Pitch-regulated System

The technology in the field of wind turbine has been greatly improved in recent years. Pitch-regulated wind turbine is believed to be superior to other types of wind turbine due to its features such as high efficiency and ideal starting and braking performance. Based on the research of "Megawatt variable speed and constant frequency wind turbine", one of the state "863" projects in SUT, this paper is meant to analyze the pitch-regulated system, the key technology of wind turbine. Following aspects are discussed in this thesis:The calculation method and formula of the pitching moment of megawatt wind turbine are obtained. Based on the foregoing calculation formula and blade parameter, the calculation program of SUT-1000 pitch-regulated driving moment has been drawn up with the help of MATLAB. Hereafter the pitch-regulated mechanism of SUT-1000 is designed on the result of previous calculation that the major factor influencing the pitching moment is M_c.Hydraulic driving system is designed under the condition that the working condition of wind turbine is fully considered. The Operating principle of hydraulic system and oil path under all kinds of working condition are explained in great detail.The linear mathematical model about opening pitch and closing pitch is established, with features of pitch-regulated control taken into account. Based on linear mathematical model the closed-loop control system is built with PID controller, and then pitch-regulated control simulation is performed. It is derived that opening pitch response speed is lower than closing pitch response speed in theory.Finally, experimentation workbench is built and program of host computer and slave computer is worked out. The response curve and PID parameter are obtained after hydraulic system and pitch-regulated control experimentation is performed. It is proved that foregoing mathematical model is correct and it is advisable to adopt different control methods in thecourse of opening pitch and closing pitch. Pitch-regulated running experiment with loading is conducted at factory, and its result is satisfying.