Research On Vriable-Speed Constant-Frequency Wind Power Generation's Main Controller

As a sustainable green resource which can be capitalized limitlessly, the development of wind resources has been paid a lot of attention to. With human's huge need for energy, the wind power generation industry grow up in an extensively commercialized way and thus bring a rapid development in the technology of wind power generation. In recent years, as the Variable Pitch technology developed, VSCF doubly-fed wind generators become mainstream wind generators.Within the various mechanisms related with wind power generation, the control system plays an important role in maintaining the normal operation of the generator. Thus the controlling technology of control system is a key technology of wind power generation, and precise control and perfect function are the conditions for the secure, stable and effective operation of the generator units.As most of the wind fields are located in harsh natural conditions without people in charge, the control systems are required to be highly reliable and perfectly functional. This thesis is to study the main function of control systems on the basis of VSCF doubly-fed wind generators, put the emphasis on the design of generator's main controller and realize the experimental platform of main controller in the laboratory.This thesis analyzes the power generation principle of VSCF doubly-fed wind generators and the systematical structure of the whole generators. A classification is made according to the variance of wind speed and rotate speed and the generator is controlled by stages. In this process, the controlling task and functional requirements are analyzed and controlling strategy of entire generator is formulated. In the study of the process in which the maximized wind power is captured, through the comparison of different methods, tracking the optimal power speed curve method is chosen as the best wind power tracking algorithm.For the stage of adjusting the pitch of blade, when the output power of generator reach the maximal amount above the rated wind speed, the variable propeller controller is put into use to chase more wind power. This thesis adopts the method of PI gain scheduling control on the basis of traditional PI controller to realize the PI regulation of variable parameters in different stages, thus improve the controlling effectiveness.According to the task of main control systems and consideration of the hardware's performance, the Siemens IPC is chosen as hardware basis of the main controller combining with embedded PLC—SIMATIC WinAC to realize controlling function. The various field input and output signals of units are collected by distributed I/O system. The functions of main software are designed according to the requirements of systems, and well-functioned field operation screen and long-distance upper computer are also developed.