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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Loss analysis and design of a novel soft switching converter

何永財, Ho, Wing-choi. January 1997 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
2

Applying genetic algorithms to fly-back converter design

Fivaz, Jean 27 February 2012 (has links)
M.Ing. / This thesis investigates how genetic algorithms may be applied to solving for flyback converter design optimization. The genetic algorithm finds the combinations of components and switching frequency required for a capable, efficient and small fly-back solution. Ways of effectively evaluating the proposed solutions are discussed in light of the circuit theories of power electronics, and specifically, fly-back converters. Applying component data effectively to the evaluation process is addressed, especially in the light of the optimization goals. A solution evolved by a genetic algorithm is tested and compared against a prototype designed through conventional methods.
3

Hardware design and protection issues in an AC/AC converter

Faveluke, Alex 25 August 1997 (has links)
An AC/AC converter has been designed and implemented for the purpose of providing a modular drive system with a Brushless Doubly-Fed Machine (BDFM.) This converter is to be used in laboratory testing and also as part of a demonstration system in the field. All hardware needed to start and run the BDFM is now consolidated into a single NEMA standard frame electrical equipment box. This allows easy transportation and setup of the drive system, and will enable the BDFM drive system to be directly compared with existing induction machine based drive systems. Converter subsystem overviews in the body of the text and comprehensive schematics in the appendices of this thesis describe all circuitry included in the drive system. Sufficient construction detail is given to allow for duplication of this converter by qualified technical personnel. While not tailored for mass production, this converter may provide a starting point for a commercially viable design. / Graduation date: 1998
4

Development of silicon based direct conversion receivers

Chakraborty, Sudipto 12 1900 (has links)
No description available.
5

Analysis and design of multiple-output forward converter with weighted voltage control

Chen, Jing 03 October 2007 (has links)
This work presents the modeling and analyses of multiple-output forward converters with weighted voltage control. Based upon the analyses, the systematic design methodologies and design tools are provided. A power stage de model including all the major parasitics, which are detrimental to the output voltages, is derived. A nonlinear programming based design tool is developed to search for the weighting factors. Five methods of stacking secondaries to improve cross-regulation are presented, and the improvement of cross-regulation is quantified. A small-signal model of the multiple-output converters with coupled output filter inductors and weighted voltage control is established. The small-signal characteristics are studied, and the model shows that the system behavior is very sensitive to the coupling coefficient, which has been reported, but never been quantified. The pole-zero interlaced condition is derived. A current-mode control small-signal model is also presented, which can predict all the observed phenomena of current-mode control. Compensator design is discussed for different types of power stage transfer functions for both voltage-mode and current-mode control. / Ph. D.
6

High-frequency Analog Voltage Converter Design

Xu, Ping 04 May 1994 (has links)
For many high-speed, high-performance circuits, purely differential inputs are needed. This project focuses on building high-speed voltage converters which can transfer a single-ended signal to a purely differential signal, or a differential input signal to a single-ended signal. Operational transconductance amplifier (OTAs) techniques are widely used in high-speed continuous-time integrated analog signal processing (ASP) circuits because resistors, inductors, integrators, buffers, multipliers and filters can be built by OT As and capacitors. Taking advantage of OT As, very-high-speed voltage converters are designed in CMOS technology. These converters can work in a frequency range from DC (OHz) up to lOOMHz and higher, and keep low distortion over a± 0.5V input range. They can replace transformers so that designing fully integrated differential circuits becomes possible. The designs are based on a MOSIS 2μm n-well process. SPICE simulations of these designs are given. The circuit was laid out with MAGIC layout tools and fabricated through MOSIS. The chip was measured at PSU and Intel circuit labs and the experimental results show the correctness of the designs.
7

Coupled simulation of an indirect field oriented controlled induction motor drive

Legesse, Michael. January 2008 (has links)
Conventionally, system simulations of induction motor drives use lumped parameters model of the motor. This approach assumes motor parameters to be constant during the entire operation of the drive. Unfortunately, these are known to vary significantly over the operating range of the motor due to factors such as magnetic saturation, skin effects, and operating temperature. The variations in motor parameters affect motor output and control parameters resulting in degraded drive performance. One way of overcoming this problem is by coupling the field model of the induction motor with the drive simulation. By replacing the lumped parameters model with the field model, the influence of different operating conditions on motor parameters can be taken into account dynamically. In this thesis such an approach is investigated by coupling the finite element analysis of an induction motor with the system simulation of the field oriented controlled drive. The results obtained for the coupled simulation are promising and possible future works to make this method of simulation more accurate and reliable are recommended.
8

Coupled simulation of an indirect field oriented controlled induction motor drive

Legesse, Michael. January 2008 (has links)
No description available.
9

Energy conversion unit with optimized waveform generation

Sajadian, Sally January 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The substantial increase demand for electrical energy requires high efficient apparatus dealing with energy conversion. Several technologies have been suggested to implement power supplies with higher efficiency, such as multilevel and interleaved converters. This thesis proposes an energy conversion unit with an optimized number of output voltage levels per number of switches nL=nS. The proposed five-level four-switch per phase converter has nL=nS=5/4 which is by far the best relationship among the converters presented in technical literature. A comprehensive literature review on existing five-level converter topologies is done to compare the proposed topology with conventional multilevel converters. The most important characteristics of the proposed configuration are: (i) reduced number of semiconductor devices, while keeping a high number of levels at the output converter side, (ii) only one DC source without any need to balance capacitor voltages, (iii) high efficiency, (iv) there is no dead-time requirement for the converters operation, (v) leg isolation procedure with lower stress for the DC-link capacitor. Single-phase and three-phase version of the proposed converter is presented in this thesis. Details regarding the operation of the configuration and modulation strategy are presented, as well as the comparison between the proposed converter and the conventional ones. Simulated results are presented to validate the theoretical expectations. In addition a fault tolerant converter based on proposed topology for micro-grid systems is presented. A hybrid pulse-width-modulation for the pre-fault operation and transition from the pre-fault to post-fault operation will be discussed. Selected steady-state and transient results are demonstrated to validate the theoretical modeling.
10

A new family of dc-dc-ac power electronics converters

Darabi, Mostafa January 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis proposes a family of non-isolated bidirectional converter in order to interface dc and ac variables. Such power electronics solutions guarantee: (i) bidirectional power flow between dc and ac converter sides, (ii) independent control in both converter sides, (iii) high level of integration with a reduction of one power switch and its drive circuits, (iv) implementation of two functions by using a unique power conversion stage and (v) reduction of the capacitor losses. Despite proposing new power converter solutions, this thesis presents an analysis of the converters in terms of pulse-width-modulation (PWM) strategy, dc-link capacitor variables, and suitable a control approach. Solutions for single-phase, three-phase and three-phase four-wire systems are proposed by employing a converter leg with three switches. A possible application of this converter is in Vehicle-to-Grid (V2G) systems and interfacing dc microgrid with a utility grid. In addition to the new power electronics converters proposed in this thesis, an experimental setup has been developed for validation of the simulated outcomes. The proof-of-concept experimental setup is constituted by: DSP, Drivers & Integrating Board, Power Supply and, Power Converter & Heat-Sink .

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