Fu, Colin Leong Chee (1999) Power-control design of resonant converters. PhD thesis, University of Warwick.

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Abstract

Novel design techniques are presented for load-resonant and quasi-resonant converters for
use in, for example, arc-welding and fan-load power supplies. Both converters are capable of
very high switching frequency over a wide range of output power, with high efficiency and the
presentation of near-unity power factor to the primary power supply.
Previous work, by the author and his colleagues, has produced. a frequency-domain approach
to produce circuit-designs for use in load-resonant converter applications. This design technique,
although simple and straight-forward to understand, suffers by requiring some rather tedious
trial-and-error algebraic and arithmetic manipulations albeit computer assisted. In this thesis, a
systematic way of designing such circuits, based on Gr6bner Basis ideas, is explained, developed
and compared with the previous best-practice design method. By employing the Gr6bner Basis
techniques to synthesize electrical circuits, an entirely novel approach to the design of series-parallel
load-resonant converter circuits is presented. This has led to the formulation of a new
output-power control methodology in the design of the converters. These techniques produce
output-power-control designs that have superior properties, compared with other established
methods, in the sense of their simplicity, robustness and flexibility.
It is found that the methodology can be further extended to alter any resonant circuits and,
hence enables multilevel-output power to be controlled without involving complex control and
advanced mathematical theories, while still preserving the desirable characteristics of resonant
switching. The technique is, in fact, far more generally useful in the circuit-design/synthesis
arena than the specific load-resonant-converter application for which it was developed.
The novel technique used to vary the speed of an induction motor is found to be promising.
Various test results are presented based on an experimental system.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Electric current converters -- Design and construction, Electronic circuit design, Gröbner bases
Official Date:	December 1999
Dates:	Date Event December 1999 Submitted
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Flower, John
Sponsors:	Sarawak Foundation
Extent:	xvii, 188 leaves
Language:	eng

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