Publication Date
2018
Document Type
Dissertation
Committee Members
Marian K. Kazimierczuk, Ph.D. (Advisor); Ray Siferd, Ph.D. (Committee Member); Saiyu Ren, Ph.D. (Committee Member); Yan Zhuang, Ph.D. (Committee Member); LaVern Starman, Ph.D. (Committee Member)
Degree Name
Doctor of Philosophy (PhD)
Abstract
As the trend towards vehicle electrification, renewable energy, smart systems is increasing, the key enabling technology such as power electronics are becoming ever more important. Power electronics is the vital component of many applications in automotive, computer, data-centers, medical, aerospace, communication, green-energy, and manufacturing sectors. Major advancements in high efficiency, high power density, high voltage conversion ratio, and fast dynamic response power-electronic converters is evident both in research and industry, particularly at the topology level. A major contribution of this dissertation is the analysis, design, development, and dynamic modeling of a novel impedance-source topology termed as A-source converter, which potentially satisfies all the above factors. The pulse-width modulated (PWM) A-source converter exhibits the following attractive features: (a) high voltage step-up with low parts count, (b) continuous input current, (c) magnetically coupled impedance-source nature, (d) scalable design, and (e) configurable as dc-ac inverter or dc-dc converter. In this dissertation, the steady-state analysis of the converter waveforms, the derivation of the component design equations, and component voltage and current stresses are derived for the converter operated at continuous-conduction mode (CCM). A design procedure is also provided for a converter operated at a supply voltage of 12 V, output voltage of 48 V, and switching frequency 50 kHz. Another major contribution of the dissertation is the development of the dynamic model of the converter power-stage and that for closed voltage-mode operation. By the principle of circuit-averaging, the expressions for the averaged transistor current and diode voltage are obtained and an equivalent dc model is developed. By perturbing the steady-state model about its dc operating point and performing linearization, the small-signal model is developed. Subsequently, the small-signal transfer functions and network impedances are derived. The dynamic frequency- and time-domain properties of the power-stage are analyzed in details. Voltage-mode control of the A-source converter is designed and characterized. The closed voltage-loop transfer functions are derived. A laboratory prototype of the A-source dc-dc converter was designed, built, and tested for the above-mentioned specifications. The open-loop power-stage and closed voltage-loop transfer functions were measured using the gain-phase analyzer. An excellent agreement between the theoretical and measured results were observed, thereby, validating the predicted results. The A-source topology belongs to the class of boost-type high voltage step-up converters. Such boost-type converters have non-minimum phase properties and the dynamic models contain a right half-plane (RHP) zero. Future work in this area constitutes a study of the stability and sensitivity of the RHP zero to change in supply voltage and load resistance.
Page Count
175
Department or Program
Engineering; Electrical and Computer Engineering
Year Degree Awarded
2018
Copyright
Copyright 2018, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.
ORCID ID
0000-0002-8532-6813
