Research On The Single-Machine Electric Control Technology For MW-Scale Wind Turbine Generators--Reactive Power Compensate And Yaw Control System

As an important kind of generating form, wind power generation has caused more and more concern recently. In order to push forward sustainable development of wind power generation, "The Research of the MW-Scale Stall-regulated Wind Turbine Generators and the Key Parts" has been ratified by the Ministry of Science and Technology as one of the National High Technology Research and Development Plan (863 Plan). We shall form self exploit ability soon by ourselves developing and trackling some key technology, such as the total design, Electric Control System (ECS) and the design of the rotor blades, etc. during the process of localization of MW-Scale Wind Turbine Generators (WTGs).As an important part of the project of developing an ECS for MW WTGs, the thesis makes overall theoretic analyses and experimental studies on reactive power compensate control system and yaw control system.According to the total requirments of the ECS, a compensate way of shunting capacitors can be properly chosen which is compatible to the system by analyzing the reactive compensate theory and comparing compensate ways systematically. The thesis makes deep and comprehensive studies about the selection of the control methods and the control physical parameters and establishes a reactive power compensate control strategy to avoid possible power oscillation when switching compensating capacitors. In addition, the emphasis of the thesis is the use of Fast Fourier Transform (FFT) in reactive power compensation. Meanwhile the thesis designs hardware structure of the reactive power compensator which use TMS320F240 as the control core, and the software used in the system haved been debugged and complied based on the idea of modularized software design too. The Digital Signal Processor with advantages of its higher speed and powerful calculation ability is applied to calculate the reactive power that need to be compensated to follow the change of reactive power and add or cut capacitor banks to realize real-time and dynamic compensation periodically and automatically. The automatic tracking of sampling frequency to fundmental frequency is realized by adaptive sampling in order to improve the accuracy of measurement. The feasibility and validity of the hardware and software implementation for the reactive power compensate control system is verified.On the basis of analyzing the control process completely, the thesis designs yaw control system for WTGs using 89C51 single-chip computer as a main control unit. Thecontrol system faces the wind actively by logical control and is controllable during the process of facing wind. It can exactly trace wind direction and automatically release winding cable caused by the yaw. The thesis accomplishes the software and hardware design of the control system based on sensors of wind direction.