Abstract
M.Ing (Electrical and Electronic Science)
High frequency magnetic components have significant advantages related to cost
and physical size compared to their low frequency counterparts. The advent of
high frequency power switch technology made the transformer frequency a
variable and recent advances in this field have been ever pushing the switching
frequency of higher power converters. Although high frequency inductors and
transformers have been used and applied extensively to an increasingly broad
range of applications over recent decades, analysis and design of these devices
involves certain difficulties, related to extra losses due to eddy currents as well
as smaller cooling surfaces, to the developer and designer. Numerical
simulations of eddy currents in windings are slow, if not impossible in many
cases, due to the large mesh impositions required in order to converge. Eddy
currents and thermal constraints impose limitations on flux- and current
densities, complicating the design. As yet, a convenient means of design,
analysis and optimization of the physical magnetic topology does not exist.
In this study, a method for analysing eddy currents in windings, usmg a
combined analytical and numerical approach, is presented and implemented in
a CAD tool. The one dimensional solutions for eddy currents in strip conductors
are written in a more flexible form.
A new approach to magnetic component design, called scant modelling, is
presented and applied to two practical examples. The scant model comprises a
minimum number of functional and form parameters in analysing and optimizing
a design, but considers eddy current effects, thermal constraints and the effects
of physical size and shape of core and windings at high frequencies.