| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 95 === The thesis presents a digital driving system of a micro-stepping motor using the full bridge dc-ac power converter. The micro-stepping control of two-phase stepping motor has been realized with improved accuracy. With current compensation based on reactive power calculation, the current closed-loop control system makes the stepping motor current waveform close to an ideal sine wave and reduce the torque pulsation. Thus, the stepping motor runs more smoothly and has better performance. In the thesis, smooth-speed curve is used as the speed-command which makes the micro-stepping motor rotate more smoothly.
The thesis uses a low-cost, 32-bit digital signal processor, TMS320LF2808, to implement the micro-stepping drive. The current control of pulse-width modulation and smooth-speed curve is set up by software to reduce circuit complexity. Each step can at most be divided into 256 microsteps. When the motor runs at 15 rpm, the total harmonic distortion of current deceases from 7.65% for 4 microsteps to that of 4.43% for 128 microsteps. On the other hand, if efficient control technique is introduced for no-load operation at 15 rpm and 128 microsteps, the maximum current required reduces form 2.25A to 1.25A. The feasibility of the system is verified experimently.
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