Research On Maximum Power Point Tracking For Variable Speed Constant Frequency Doubly Fed Wind Power Generation System

With the growing demand for the energy all over the world, gradually disappearing of the conventional energy sources such as fossil fuel, and the growing problem of the environment pollution, human is paying more and more attention to the use of renewable energy. As a kind of green energy, wind energy has become the focus of the attention. Wind power generation is an effective way to use wind energy. The characteristic of the wind turbine, which can capture the wind power, determines that it will get different wind energy at different speeds. In order to make full use of the wind energy, the research on the Maximum Power Point Tracking (MPPT) becomes an effective method to improve the efficiency of wind power gradually.This dissertation introduces the trend of the development of wind power generation, wind turbine emulation technology and the state-of-arts of the research on the AC excited Doubly Fed Induction Generator (DFIG) technology. Based on the fundamental of Variable Speed and Constant Frequency (VSCF) wind power scheme, the operation status is analyzed, and the scheme of MPPT and power transmission processing of the unit with different power are presented in details。Meanwhile, the mathematical model of DFIG in d-q coordinate system is established, and the decoupled control strategy of DFIG active & reactive output power based on grid voltage oriented vector control is discussed, and the output power of the AC excited DFIG is controlled to achieve the MPPT scheme.This dissertation analyzes the operational principle of the wind turbine, a mathematical model of the wind turbine is set up, a simple effective speed and direct torque control emulation scheme is made up, a wind turbine emulation platform based on the DSP and DC motor is built up, a upper machine interface by utilizing LABWINDOWS is developed, and apply them into VSCF wind power system which is based on the DFIG. It realizes the operation status of the wind turbine emulation when wind turbine works in different wind velocity and the different rotate speed, and has satisfy the requirement of the research and design for MPPT of the wind power system. Using this platform, lead to the...