Abstract
The main purpose of this thesis is to develop a soft-switching converter-fed switched reluctance motor (SRM) drive and perform its speed control, such that it can possess higher conversion efficiency and better speed control performance. First, in order to facilitate the establishment of SRM drive and perform the proposed researches, the structural features, the switching operation and the developed torque of a SRM are first studied. Then some of the existing hard-switching converter circuits for powering SRM are surveyed. Accordingly, a modified Miller converter-fed experimental SRM drive is established. And its driving control performance is evaluated by some measured results.As generally recognized, soft-switching is an effective means to reduce the switching losses of power converters. In this thesis, a zero-voltage-transition (ZVT) soft-switching converter for SRM is developed. It is formed from the traditional modified Miller converter by adding an auxiliary resonant circuit. No extra voltage and/or current sensors are necessary. And the soft-switching of main switches can easily be obtained by applying suitably modified switching control signals for the main and auxiliary switches. Having derived the governing circuit equations in various operation modes, a design procedure is proposed to systematically find the constituted components of the proposed soft-switching converter. The performance of the designed converter is demonstrated by some simulation and experimental results. Through employing the developed converter, the dynamic responses of motor drive remain almost unchanged. As to the quantitative speed control issue, the dynamic model of the established SRM drive is first estimated at nominal case. Then a two-degrees-of-freedom controller (2DOFC) and a linear model following controller (LMFC) are designed and applied to let the controlled SRM drive possess good model following speed control responses.