| Summary: | 碩士 === 國立交通大學 === 電機學院電機與控制學程 === 99 === This thesis proposes a novel sliding-mode control for the wind energy conversion systems to reach the energy optimization. Since the output power of wind electrical generators tends to interact with wind speed, it is required to operate at the maximum power point so as to enhance the efficiency of wind electrical generators. By tracing the optimal tip speed ratio, the optimal output power and the optimal rotational speed are obtained. After comparing to such optimal speed, the bias of the generator rotational speed is determined and used as the reference to adjust the controller. To design the sliding-mode control, first choose a stable sliding-mode require for the control purpose. Then, construct the control algorithm to drive the system trajectory into the sliding mode in a finite time. As for the chattering phenomenon, it is eliminated by substituing the sliding surface with a sliding layer. In addition, a first-order high pass filter is employed to approximate the undersirable differential operation in the control rule, not to excite high frequence noise. Finially, the simulation of MATLAB/SIMULINK is adopted to demonstrate the robustness of the sliding-mode control at various speed, and the effects on the control accuracy caused by the use of different coefficients in the estimator and control rules. From the numeric results, the proposed sliding-mode control indeed completes the optimal wind energy conversion successfully.
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