Abstract
M.Ing. (Electrical and Electronic Engineering)
In an attempt to build a 2000A transistor switch. with the possibility of integrating the electromagnetic
components, different transistor switch and transformer configurations were investigated and
compared.
A standard high frequency monolithic transformer was investigated for the integration with the rest
of the circuit. Different problems were found as will be discussed. A saturation of the transformer
to one side occurred, and a control circuit for this was developed and is discussed. A different approach to transformers, matrix transformers, was investigated for the application
in high current, low voltage supplies, such as a compensating supply for a compensated Darlington
transistor. From the matrix transformers a new kind of transformer connection style, namely a
symmetric transformer, followed. The symmetrical transformer was investigated for the possible
use in monolitic transformers, and compared with halfbridge, fullbridge and push-pull transformer
configurations. It was decided to proceed further with matrix transformers.
A design of a 400A 1.5Vsupply, was done to serve as a compensating supply in a 2000A compensated
Darlington transistor switch. The supply was built up and analysed.
Different switch configurations were investigated for use as possible transistor switches. The
compensated Darlington was considered to be the best. Unexpected switch off problems occurred.
These are discussed and an optimum switch off topology is suggested.
A 2000A transistor switch was designed and built. Full current could not be reached and results are
presented up to 650A.