Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 86-87).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 269-274).

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 78.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 73-74).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 240-247).

M.Ing. (Electrical & Electronic Engineering) / Switching losses in power electronic converters can be reduced by using snubbers, or resonant circuits. Simple snubbers can be implemented without much effort, but then energy is still dissipated, which reduces the efficiency of the converter. Regenerative snubbers are known, but these usually require complicated additional circuits. The use of nonlinear capacitors as turn-off snubbers has been investigated, and proved profitable. The main reason for this is the much smaller amount of energy which is stored in the the nonlinear capacitors, compared to linear capacitors. Resonant circuits reduce switching losses by allowing switchings to occur when the voltage across the switching device, or the current through the switching device is zero. This effect is called soft-switching and to obtain this, resonance between an inductor and capacitor is usually involved. Resonant circuits have the disadvantage that the installed switching power cannot be used optimally. This drawback has been reduced by using a saturable inductor in the resonant circuit. This thesis considers the use of both nonlinear capacitors and nonlinear inductors in a resonant phase arm. It was found that the nonlinear resonant elements lead to very low overdimensioning of the switching devices, and minimal switching losses in such a phase arm. Very few additional components are used, which keeps the cost of the converter down. A 1.5kW converter was constructed in which the double nonlinear resonant phase arm was implemented. This converter was investigated both experimentaly, and by means of computer simulations. The converter is also compared with the current state of the art. It is concluded that resonant phase arms with both. nonlinear inductors and nonlinear capacitors can function effectively in power electronic converters. Some important advantages are also assosiated with the use of the double nonlinear resonant circuit.

M.Ing. (Electrical & Electronic Engineering) / In recent years, there has been a renewed interest in the synchronous reluctance machine, because it holds so many promises according to the mathematics. In the past very little research has been done in this field, due to the problems of controlling the machine and the necessary technology had not yet- been developed. When the machine is running synchronously, it can be very accurately controlled and is therefore suited for applications in the paper or textile industry. In this dissertation the possibility of accurately controlling the machine without the use of a position/speed sensor on the rotor will be investigated.

A dual-excited synchronous machine is designed and constructed. A power system is simulated using the machine and a medium length transmission line joined to the laboratory bus energized from B.C. Hydro which is considered the infinite bus. The effect of supplemental excitation control on power system stability is investigated. Feedback control is used in both the direct and quadrature fields. Torque angle, speed, power and terminal current signals are compared in their damping action. The response is also calculated from a ninth order mathematical model. It is found that the shaft speed is the best supplemental signal and that the direct and quadrature fields are equally effective in dynamically controlling the machine when operating near rated output. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Subsynchronous resonance (SSR) occurs in a series-capacitor-compensated power system when a mechanical mass-spring mode coincides with that of the electrical system. In this thesis, a complete high order model including mass-spring system, series-capacitor-compensated transmission line, synchronous generator, turbines and governors, exciter and voltage regulator is derived. Eigenvalue analysis is used to find the effect of capacitor compensation, conventional lead-lag stabilizer, loading and dampers on SSR. Finally, controllers are designed to stabilize multi-mode subsynchronous resonance simultaneously over a wide range of capacitor compensation. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate