| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 93 === This thesis is concerned with design and implementation of a unity power factor, low current harmonics drive for switched reluctance motors (SRM). Other than traditional diode-bridge rectifier, the proposed system uses single-phase, single-switch, three-level boost AC/DC converter to obtain low input current harmonics and a stable DC voltage for SRM inverter. Closed-loop controls of speed and current are conducted to provide fast dynamic system response by embedded controllers using the feedback signals of output current from current sensor as well as the rotor position and speed through Hall-effect sensor. In addition, a fast power compensation algorithm is proposed to balance the power between input and out in order to accelerate the DC-bus voltage response and reduce the voltage ripples.
The performance of the boost converter is first simulated by Matlab/ Simulink. A digital signal processor (TMS320LF2407) is applied to implement digitized control of the proposed system. When dc-link is at 200 volts with 650 W resistance load, the power factor and the total harmonic distortion of current are 0.99 and 5.21%, respectively. The proposed speed and current controls yield better current response and smoother output torque. Besides, fast power compensation and smaller voltage ripples at dc-link are achieved as expected. Experiments are given to justify the analysis.
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