Thesis (Ph. D.)--Columbia University, 2007. / Includes bibliographical references (leaves 183-200).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 184-200).

Thesis (Ph.D.)--University of Florida, 2005. / Title from title page of source document. Document formatted into pages; contains 194 pages. Includes vita. Includes bibliographical references.

M.Ing. (Electrical & Electronic Engineering) / The technology of the use of electronic devices as power switches is still being developed. Because of the increasing demand for low mass and cost, the switching frequency must be as high as possible. The limiting factor for the frequency is the energy loss which is dissipated in the semiconductor crystal during each switching-transient. If tllis switching loss can be reduced, a higher frequency can be obtained. The switching loss is due to the non-instantaneous switching process of the semiconductor device. For the reduction of this switching loss, the device must be switched as fast as possible via its control-electrode. Further improvement can be obtained through the use of snubber networks. This thesis considers the bipolar high-voltage transistor as a power switch. The unfavourable switching loci of the transistor- switch is discussed in chapter 1. In chapter 2 the basedrive during transistor turn-off is investigated, in order to reduce the turn-off time. The following chapters de;al with the use of snubber circuits, which relieve the transistor during turn-on and turn-off. The advantages, as well as the disadvantages and limitations of snubbers are discussed. After the linear turn-off and turn-on snubbers have been treated, the non-linear turn-on snubber, which uses a saturable inductor, will be considered from an experimental point of view. The results show that this snubber is very effective in relieving the transistor during turn-on. In chapter 7 the non-linear turn-off snubber is treated on an experimental as well as on a mathematical bas e . Cri teria, which must be satisfied for realisation of a practical nonlinear capacitor, is also laid down. Because of the fact that a first order snubber is always loading the transistor during the complimentary switchin,]-transient, chapter 8 deals with a second order snubber, which consists of both a capacitor and an inductor. Experimentally it was found that the turn-on time is reduced with the use of a turn-on snubber, while the turn-off time is increased with the use of a turn-off snubber. In chapter 9 the physical behaviour of the switching processes is investigated, after which the influences of the snubbers on the switching times is explained qualitatively...

Due to the increasing trend towards energy saving of white goods appliances and the commercial viability of power electronic components, there has been an expansion in the use of solid state electronics and variable frequency drive motors in these applications. However, a major drawback of using such energy efficient loads is the introduction of current harmonics onto the local distribution grid. Furthermore, the proliferation of such devices elevates the harmonic content of the supply voltage and the ensuing potential impact on residential distribution networks. This thesis investigates the harmonic content generated by some representative household appliances and suggests a solution to minimize current harmonics by means of active filtering. An active filter circuit is proposed and simulations will be undertaken to compare filter performance when used as an active front end versus a feeder input compensator. Further, a hardware design of the filter was implemented to experimentally verify the filter operation. / Thesis / Master of Applied Science (MASc)

No description available.

Electric utilities are increasingly incentivized to integrate new renewable energy generation resources to their systems; however, operations-related issues arise due to the non-dispatchable and stochastic nature of these renewable energy sources. These characteristics lead to a variety of issues for utilities, among which are voltage fluctuations, balancing dispatch against ramping events, short-duration power fluctuations, and the need to invest in peaking generation facilities just to accommodate the renewable energy. A traditional solution to these issues is to employ renewable generation-following techniques using either newly constructed gas peaking plants, or by shifting existing generation resources to this following responsibility. Unfortunately, use of these traditional methods introduces a new set of issues; namely, wear-and-tear due to more frequent cycling, reduced capacity factors, decreased plant efficiency, and additional investment in large-scale captital infrastructure. This thesis proposes an alternate solution: a utility-owned and utility-managed battery energy storage system sited on residential customer premises, deployed at scale to create a 200MW / 1320MWh distributed network of Residential Battery Energy Storage Systems (ResBESS). In partnership with Portland General Electric (PGE) stakeholders, a conceptual design was prepared for a ResBESS unit, a laboratory prototype of a single such storage system was constructed, and an alpha prototype is now being installed in a field demonstration project in Milwaukie, Oregon within PGE's service territory. The motivations, design constraints, and design methodology of the laboratory prototype are presented and discussed, and preliminary work from the field prototype build is examined to demonstrate the results of the thesis project.

M.Sc. / Please refer to full text to view abstract

M.Ing. / Inverters are daily used in industry, and to a large extent, as induction motor drives. Power levels of inverters vary from a few watt to several megawatt. The most common part of inverters is a phase arm or a pole, consisting of two power electronic switches and two freewheeling diodes. The hard switched phase arm is the standard in industry due to simplicity and cost. Regenerative snubbing is often used at larger power levels to reduce losses in the inverter. Some aspects of the non-linear resonant pole inverter, such as regenerative snubbing and zero voltage switching, are investigated. It is obtained by utilising a non-linear resonant tank. Low current stresses permit the optimal use of the power electronic switches. The non-linear resonant pole inverter can replace the hard switched inverter, with no restriction with respect to power levels. Experimental and analytical modelling was employed to investigate some aspects, such as controllability, losses and feasibility.

by Choi Yeung Bun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 105-109). / Abstracts in English and Chinese. / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Project Overview --- p.3 / Chapter 1.2 --- Thesis Organization --- p.4 / Chapter CHAPTER 2 --- REVIEW ON CLASSICAL CLASS-E --- p.6 / Chapter 2.1 --- Class-E Concept --- p.6 / Chapter 2.1.1 --- Waveform Shaping for Current-Source Active Device --- p.6 / Chapter 2.1.2 --- Waveform Shaping for Switch-type Active Device --- p.8 / Chapter 2.1.3 --- Optimum Class-E conditions --- p.11 / Chapter 2.2 --- Class-E Circuit Operation --- p.12 / Chapter 2.3 --- Analysis and Synthesis Methods --- p.14 / Chapter 2.3.1 --- Rabb´ةs work --- p.15 / Chapter 2.3.2 --- Zulinski's work --- p.16 / Chapter 2.3.3 --- Kazimierczuk's work --- p.17 / Chapter 2.3.4 --- Collective Efforts --- p.18 / Chapter 2.4 --- Additional Amplifier Configurations --- p.20 / Chapter 2.5 --- Conclusion --- p.23 / Chapter 2.5.1 --- Potential for Microwave Applications: --- p.23 / Chapter 2.5.2 --- Major Obstacles --- p.23 / Chapter 2.5.3 --- Outstanding Issues --- p.24 / Chapter 2.5.4 --- Requirements for new Analysis Method --- p.25 / Chapter CHAPTER 3 --- NEW THEORETICAL DEVELOPMENT --- p.26 / Chapter 3.1 --- Basic Formulation --- p.27 / Chapter 3.1.1 --- Set up Time Equations --- p.28 / Chapter 3.1.2 --- Complex Fourier Series Decomposition: --- p.31 / Chapter 3.2 --- General Analysis --- p.34 / Chapter 3.2.1 --- Load Network Coupling --- p.34 / Chapter 3.2.2 --- Numerical Verification --- p.37 / Chapter 3.3 --- Optimization --- p.40 / Chapter 3.3.1 --- Frequency Domain Class-E Definition --- p.42 / Chapter 3.3.2 --- Power Approach --- p.45 / Chapter 3.3.3 --- Harmonic Reactance Approach --- p.50 / Chapter 3.4 --- Summary --- p.53 / Chapter CHAPTER 4 --- PERFORMANCE EVALUATIONS --- p.55 / Chapter 4.1 --- Benchmarks --- p.55 / Chapter 4.2 --- Non-Zero Turn-on Resistance Variations --- p.59 / Chapter 4.3 --- Frequency Variation --- p.62 / Chapter 4.4 --- Fundamental Load Variations --- p.64 / Chapter 4.5 --- Harmonic Loading Variations --- p.68 / Chapter 4.6 --- Package and Other Effects --- p.74 / Chapter 4.7 --- Summary --- p.77 / Chapter CHAPTER 5 --- EXPERIMENTS --- p.78 / Chapter 5.1 --- Design Methods --- p.79 / Chapter 5.2 --- 500MHz Class-E PA --- p.81 / Chapter 5.3 --- 1.8GHz PHEMT Class-E PA --- p.90 / Chapter 5.4 --- 3.2GHz PHEMT Class-E PA --- p.97 / Chapter 5.5 --- Conclusions --- p.102 / Chapter CHAPTER 6 --- CONCLUSION AND RECOMMENDATION FOR FUTURE WORK --- p.103 / Chapter 6.1 --- Conclusion --- p.103 / Chapter 6.2 --- Recommendation for Future Work --- p.104 / REFERENCES --- p.105