The Research And Experiment Of Direct Current Excitation Variable-Speed Constant-Frequency Wind Power Generator

Wind power generation has been developing fast recently. Various technologies of wind power generation are emerging, among which the variable speed and constant frequency (VSCF) technology attracts more and more attention for its characteristic of high-efficiency and practicability. This thesis is based on the traditional synchronous generator technologies, and VSCF wind power generation, which applies A.C excited doubly-fed induction generator (DFIG), to summarize relevant technologies, and use direct current excitation variable-speed constant-frequency wind power generator as technical scheme to introduce direct current excitation variable-speed constant-frequency generator technologies in practical use.The main contents are as follows:Firstly, synchronous and asynchronous generator theory and DFIG operation theory were analyzed in this thesis. The mathematic model of DFIG coordinate transformation, and DFIG operation characteristics were theoretically deductive and calculated, thereby established the theoretical foundation for succeeding study of the direct current excitation variable-speed constant-frequency generator.And then, the generator model was designed based on the theoretical foundation, in which the reformed three phase dynamo was applied. DSP technology was used to control the generator, which in details are control circuit design and programming.Lastly, for testifying the accuracy of the established model and control methods, a series of research and experiment were carried out on the direct current excitation variable-speed constant-frequency wind power generation system. Based on the reformed generator, DSP board, CCS software, IGBT switch circuit, control circuit and absorb circuit of it, the controllable whirling magnetic field, which is based on the direct current excitation was established.The result of the experiment proves the accuracy and dynamic controllability of the direct current excitation variable-speed constant-frequency power generator technology.However, on account of the complexity of this project, some difficulties and new questions need to be discussed further in the future.