| As the renewable and no pollution energy source, wind power is paidgreat attention by more and more country’s scholar due to energysource consume increasing daily and environment empoison beingserious gradually. Maximum wind energy capture and improving theoperation efficiency are becoming more and more important with therapid growing of the wind energy generation system。The Variable-SpeedConstant-Frequency (VSCF) wind energy generation system withDoubly-Fed Induction Generator (DFIG) has the advantages such assmaller rating excitation converter to reduce the cost.With the operation and control of an AC excited VSCF wind powergeneration system as the research subject，this dissertation made completeresearch by simulation and experiment．The main research contentsinclude：the operation theory of doubly-fed induction generator(DFIG)，decoupled control of DFIG active/reactive power output, dual PWMconverter and the study of low voltage ride through. Then, thisdissertation analyzes DFIG operation theory, including mathematic modelof DFIG’ coordinate transformation，DFIG operation characteristics，DFIG power relationship，which establishes the theoretical foundation for succeeding study. In order to control the factor at grid side of input powerand DC bus voltage, the control principle of grid side converter wasdesigned on the basis of the grid voltage oriented vector control. In orderto capture the maxim wind power and realize decoupled control of DFIGactive&reactive power, DFIG used field oriented vector controltechnique. The mechanism of the wind turbine working under asymmetricgrid voltage are analysed, and the technical solutions of wind turbine lowvoltage ride through are introduced.An integrated simulation model of AC excited VSCF wind powergeneration system was founded based on matlab/simulink platform,simulated the case of DFIG grid connection and low voltage ride through.Finally, the measured data of the wind turbine verified to the controlstrategy. |
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