| With the development of industrialization, the energy shortage andenvironmental pollution has become a serious problem, the sustainable developmentof human beings are facing crisis. Countries all over the world have research on newenergy technology to realize this problem. Althogh there are many new energytechnology, wind power generation technology has the most reliable and mostdevelopment potential.This thesis focuses on the variable speed constant frequency control strategy ofdoubly-fed wind power system. The control strategy of DC-link voltage stability c,unit power factor, doubly-fed motor variable speed constant frequencyl and powertracking will be in-depth study.First of all, the key control strategy of wind power system and converterdevelopment status is summarized and analyzed. The doubly-fed wind powergenerator of variable speed constant frequency operation principle and dynamicmathematical model is explored. The wind turbine air dynamics and maximumpower tracking control principle are also researched.On this basis, grid-side converter with grid voltage orientation control strategyand the rotor side converter with stator flux oriented control strategy of doubly-fedwind power system are in-depth discuss and study. Then the doubly-fed wind powersystem simulation model based on MATLAB will be constructed, and all thefunctions of the converter are simulated and analyzed.Finally, according to the nonlinear system filtering and optimal estimationtheory, a wind turbine torque observer based on the maximum power trackingcontrol scheme is built.This thesis proposes a new control strategy based onextended kalman filter as wind turbine’s torque observer to track maximum powercurve with no wind speed measurement. The design of wind tubine torque observercan avoid wind turbine torque measurement, realize the optimal speed maximumpower point tracking control. The simulation results prove its feasibility and have agood filtering effect to wind disturbance. |
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