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.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:3933 |
| Date | 12 February 2014 |
| Creators | Van der Merwe, Gabriel Jacobus |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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