| Summary: | 碩士 === 國立暨南國際大學 === 電機工程學系 === 97 === Induction motors have been widely used in industrial applications such as machine tools and steel mills owing to their good performance provided by their solid architecture and high initiated torque. In general, the control of induction motors is a difficult task, because the induction motor system is highly nonlinear and coupled. To ease difficulties, a field-orientation control approach is the most popularly and widely used. This thesis proposes nonlinear and adaptive design schemes for the tracking control of both rotor speed and flux amplitude of induction motors. The proposed nonlinear control design schemes is not only to stabilize the induction motor system, but also to drive all the tracking errors to converge to zero asymptotically. The system parameter uncertainties, such as the system resistance and load torque disturbance, have to be considered for realization. Therefore, the adaptive backstepping control design combining field orientation transformation is developed to achieve the speed tracking purpose. Although the flux of induction motors can be directly measured by Hall sensors, problems remain, such as degradation in mechanical robustness and increased volume. Hence, without the use of flux measurement, a backstepping observer is employed to estimate the flux amplitude, and then the nonlinear backstepping controllers. In addition, both the unmeasured state and the system parameters uncertainties are considered simultaneously two main factors to design the adaptive sensorless speed tracking controllers. Furthermore, some simulation results are given to illustrate the excellent performance of the nonlinear and adaptive backstepping design schemes applied to an induction motor.
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