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

The shortage of conventional energy and its influence on the environment makes many countries start to concern the renewable energy sources.Compared with the tide, terrestrial and other new energy, the wind energy is easier to develop and has higher performance price ratio which let it get a better development. At present, the most attention form in use is wind power generation. The wind turbine is the key component of the wind energy conversion, its ability to capture wind energy would be different under the different speeds. The maximum wind follow-up study aimed at making the wind turbine run at the best speed and use the wind energy to the maximum extent and improving power generation efficiency when the external condition is certain.The paper first introduces the research status of the wind power technology and the theoretical knowledge of wind speed, wind machines and Doubly-Fed Induction Generator(DFIG). Then, it analyzed the main operating status and power flow relation of the units under different wind speed, deduced and built mathematic models of it on the abc three phase stationary to dq phase rotating coordinate systems, put forward the stator flux oriented vector control strategy of DFIG. And then, analyzed the maximum wind tracking principle under the rated wind speed and the advantages and disadvantages of the main methods at this stage. Because of the nonlinear and multi-variable characteristics, in order to ensure the stability of the output power and improve the efficiency of the use of wind, the paper presents a fuzzy control strategy without precise control of the system mathematical model to achieve maximum wind power tracking, introduces the principle of the fuzzy controller and establishes the fuzzy controller both of generator optimal speed and closed loop.The paper uses Matlab/Simulink software to establish the simulation model, including wind speed, wind turbine, double-fed machine and fuzzy controller. Amid at the randomness and instability of the wind energy, it realizes the comparative analysis of the maximum wind power tracking simulation under the different wind speed, which verifies the correctness and effectiveness of fuzzy control systems.