| Summary: | 碩士 === 國立清華大學 === 電機工程學系 === 92 === It is known that the driving performances and torque generating capability of a switched reluctance motor (SRM) are significantly affected by many key factors, such as winding current waveform, commutation behavior and dynamic control. This thesis is mainly concerned with the development of a DSP-based SRM drive with front-end converter and its driving performance improvement via commutation controls. As generally recognized, DC-link voltage boosting is the most effective means in improving the winding current response during high speeds. To achieve this, a front-end DC/DC converter placed between battery and SRM drive is developed in this thesis. In addition to voltage boosting, this converter can also be operated as a buck-type switched-mode rectifier (SMR) to charge battery. The analysis and design of the convert circuits and control schemes in two operation modes are all performed in detail. The experimental results show that the winding current and speed dynamic response in high speeds can be much improved via the dynamic voltage boosting by the developed converter. And the SMR can also be normally operated with satisfactory performance in voltage regulation and line drawn current power quality.
As to the commutation tuning control, this thesis performe the studies about three commutation instant tuning controls, including altered and fixed, fixed and receded, and and altered simultaneously. For all control approaches, the theoretical analysis, the tuning scheme and the experimental performance evaluation are all made. According to the analysis and experimental results, a heuristic algorithm is employed to find the optimal commutation advanced angle for achieving maximum torque per ampere equivalently.
In treating the speed dynamic control, the dynamic model of the established SRM drive is first estimated at a chosen operating point. Then a 2DOF control scheme, consisting of a PI feedback controller and a disturbance robust feedforward controller, is designed and applied to let the SRM drive possess the quantitative and robust speed dynamic responses both in tracking and load regulation controls.
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