Abstract
The purpose of this investigation is to compare high frequency to low frequency (50Hz) technologies. To
accomplish this, two highly optimized candidate converters are built to champion each of the inverter
classes. Both candidates are constrained to produce the same quasi-sinusoidal output waveforms in
identical operating conditions. The low frequency inverter is designed with optimization of its output
power quality and accurate loss characterization taken in mind. A new iron core design procedure is
proposed that may predict core losses when using non-sinusoidal excitation. Experimental results indicate
that it has a promising degree of accuracy.
The high frequency candidate is designed using planar integration technology. A topology selection
determines that a critical-conduction mode flyback is the most suitable option. Components are added the
topology to allow resonant switching for reduced switching losses. Common-mode current arising from
good capacitive coupling between windings in the planar coupled inductor is reduced using charge
balancing technology. The novelty of the converter lies is in the fact that all passive components, barring
the bulk of the input capacitance and the output capacitance, are incorporated into the single planar
structure.
Finally, a comparison of the inverters is made in the categories of power quality, regulation, efficiency,
robustness and applicability to the application. The high frequency inverter is found to promise substantial
advantages over the low frequency variety in most of these elements.
Dr. I.W. Hofsajer