Department of Computer Science and Electrical Engineering
High Power Switched Mode Power Supply
William Neill
The goal of this thesis was to research, design and build a switched mode power supply suitable for a high power audio amplifier application.The bulky and expensive line frequency transformers and large passive components were to be replaced by a more efficient (electrically and spatially) design.In order to be accepted by a community of audiophiles, this new supply must also in no way affect the sound quality of the amplifier to which it is supplying power.
To achieve this, a bridge converter was chosen (to handle the power levels and provide electrical isolation).It was decided to hard switch the bridge at a frequency of 200kHz.By switching at this frequency, not only could the size of the supply be reduced, but it ensured that switching noise was kept well away from the audible frequency range and could be easily filtered with a simple, first order LC filter.
The converter was designed and built.Testing proved that this was a viable replacement for the traditional amplifier power supply.Weighing less than a kilogram, having minimal output ripple, showing excellent load and line regulation and attaining efficiencies approaching 80% in its hard switched guise, this form of power supply for this application shows much promise and warrants further development.
Through the use of resonant switching techniques, planer transformers and controlled rectifiers, efficiencies over 90% and further reductions in size should be possible in future variants.
Complete thesis:
Thesis - William Neill.pdf
Additional material:
SG3525a.pdf William
Neill - Conference Paper.pdf IRF740.pdf
STPR1220.pdfetd44.pdf