| Summary: | 博士 === 國立清華大學 === 電機工程學系 === 97 === This dissertation is mainly concerned with the establishment of a switch-mode rectifier (SMR) fed switched-reluctance motor (SRM) drive and its vibration and speed ripple reductions. First, the basics and governing equations of a SRM are studied, and a digital signal processor (DSP) based SRM drive is constructed. Secondly, the origins of vibration and the existing remedies of SRM are explored. Then five reduction control approaches are developed and comparatively evaluated. These approaches include random frequency pulse width modulation (RFPWM) with harmonic spectrum shaping, commutation advanced shift with fixed dwell angle, randomizing turn-off angle, current tail profiling without and with commutation advanced shift.
Thirdly, a single-phase SMR-fed SRM drive is established to yield good motor driving performance and line drawn power quality. In the front-end SMR, its power circuit is properly designed, and according to the observed nonlinear phenomena, a simple robust voltage control scheme is proposed. Furthermore, the adaptation of key robust control parameter is made to avoid the occurrence of nonlinear instability. Then the performance enhancements of SRM drive in vibration and dynamic responses are achieved by the proposed robust current and speed control schemes. In addition, these performances are further improved via commutation advanced shift.
For a power electronic system with higher rating, the three-phase source is a natural selection. Hence, the SRM drive is also powered by the developed three-phase single-switch (3P1SW) SMR. In handling its dynamic control, the undesired line current and output voltage ripples of this SMR are regarded as disturbances and reduced via the proposed disturbance cancellation robust controls. Under balanced three-phase case, the injected PWM compensated control voltage is synthesized from one line current through notch filtering, phase shifting and digital three-phase full-wave rectification process. And the control modification for unbalanced three-phase cases is also proposed. In making the output voltage robust control, the robust cancellation weighting factor is automatically tuned according to load level to yield compromised voltage dynamic and power quality control performances. The chaotic phenomena can be automatically avoided, and better SMR operating performance is obtained simultaneously.
Finally, this dissertation presents the speed ripple reduction control for a SRM drive via intelligent and robust error adapted current profiling approach, meanwhile the stator vibration is also effectively reduced. In the proposed approach, the leading edge of winding current command is automatically profiled by adding a compensating component, which is generated from the DC-link negative stroke spikes caused by non-ideal commutation behavior of SRM load. Then a robust current error cancellation control scheme is designed to yield the closer current waveform tracking response, and thus the smoother motor developed torque. In outer-loop, a robust speed ripple cancellation control scheme is employed to directly reduce speed ripple. Similarly, the commutation advanced shift is also applied to further reduce the speed ripple due to the improvement in torque sharing characteristics of two adjacent phase windings in commutation period. In addition, the reduced vibration and the improved torque per ampere capability of SRM are further obtained.
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