Faculty of Engineering

Permanent URI for this community

https://scholar.sun.ac.za/handle/10019.1/10

The Faculty of Engineering at Stellenbosch University is one of South Africa's major producers of top quality engineers. Established in 1944, it currently has five Engineering Departments.

News

For the latest news click here.

Browse

Browsing Faculty of Engineering by browse.metadata.advisor "Akagi, H."

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Analysis and synthesis of a 2 MVA series-stacked power-quality conditioner
    (Stellenbosch : Stellenbosch University, 1999-12) Mouton, Hendrik Du Toit; Enslin, J. H. R.; Akagi, H.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical & Electronic Engineering.
    ENGLISH SUMMARY: This thesis describes the development of a power electronic converter for a 2 MVA series-injection power-quality device. The converter is designed to interface directly with superconducting magnetic energy storage devices and operates at a nominal DC-bus voltage of 2.4 kV. In the first part of the thesis the viability of soft-switching for application to the 2 MVA converter is investigated. A new resonant turn-off snubber topology is introduced and a detailed theoretical study of the converter and snubber switching losses is carried out. An optimal snubber design procedure is derived. This is followed by a theoretical investigation of the effects of the different parasitic components on the snubber operation. In the final part of the investigation, a turn-on snubber is added to the turn-off snubber topology. An experimental evaluation of both the turn-off and combined turn-on and turn-off snubbers is carried out. In order to obtain a DC-bus voltage of 2.4 kV, a series-stacked converter topology, for use in the 2 MVA series-injection device, is investigated. A detailed theoretical analysis of the DC-bus balancing mechanisms is conducted. This theoretical analysis makes use of fundamental results from the theory of systems of linear differential equations; in particular of Floquet theory. In the final part of the thesis an experimental 700 kVA series-stacked phase-arm, operating at a 2.4 kV DC-bus voltage, is constructed. The operation of this converter is verified through a range of experiments and the measured results are compared with the theoretical predictions.