Abstract
This thesis is mainly concerned with the development of a switched-reluctance motor (SRM) drive equipped with a three-phase four-quadrant front-end switch-mode rectifier (SMR). First, an asymmetric bridge converter fed SRM drive is constructed using off-the-shelf power modules. Through properly designed current and speed control schemes, the established motor drive possesses good driving characteristics, including acceleration/deceleration, reversible and regenerative braking operations. Then the high-speed driving performance enhancement via commutation instant advanced shift and voltage boosting are explored experimentally. Next, a three-phase four-quadrant SMR is established and employed as the front-end of SRM drive. It can draw the power from the mains with power factor correction and possess regenerative braking energy recovery capability. Moreover, the DC-link voltage of the SRM drive can also be adjustable and boostable for effectively enhancing the SRM driving performance under higher speeds. For completeness, the driving characteristics of the SRM drive powered by other two types of three-phase SMRs are comparatively evaluated. In addition, a SRM position sensorless control scheme based on narrow pulse voltage injection is proposed. The voltage pulses with suited frequency and duration are injected into the demagnetized phase winding via the DSP PWM channel. The resulted winding currents are sensed and processed to yield an observed Hall signal and used for making the SRM position sensorless control. In sensorless control operation, the motor is initially started in stepping motor mode. As the speed rises to an appropriate value, the operation is changed to switched-reluctance motor mode using the observed Hall signal. And the speed feedback control is conducted using the observed speed, which is obtained from the sensed four winding currents.