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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

A Design-Oriented Framework to Determine the Parasitic Parameters of High Frequency Magnetics in Switching Power Supplies using Finite Element Analysis Techniques

Shadmand, Mohammad 2012 May 1900 (has links)
Magnetic components, such as inductors and transformers, have important effects on the efficiency and performance of switching power supplies; their parasitic properties directly impact the high frequency properties which can cause lot-to-lot variation or unanticipated and non-ideal operation. They are also amongst the most problematic components to design, often requiring numerous design-prototype-test interactions. The electrostatic and electromagnetic analysis of wound components has become more important recently to predict their performance and frequency behavior. Accurate prediction and design of winding parasitic parameters of leakage inductance and winding capacitance for high frequency inductors and transformers in switching power supplies is fundamental to improve performance, lower cost, and speed time to market. This thesis presents a methodology and process to obtain accurate prediction of the inter- and intra-winding capacitances of high frequency magnetic components. Application examples considered are a single-winding choke, a coupled inductor filter, and a multi-winding transformer. Analytical approach for determination of parasitic capacitances in high frequency magnetic components will be covered also. Comparison of the FEA results using JMAG with experimental and empirical formula results show good agreement, supporting the method as a model-based design tool with the potential to significantly reduce the design-prototype-test cycle commonly needed with sophisticated magnetic designs.
2

Electrical Capacitance Volume Tomography Of High Contrast Dielectrics Using A Cuboid Geometry

Nurge, Mark 01 January 2007 (has links)
An Electrical Capacitance Volume Tomography system has been created for use with a new image reconstruction algorithm capable of imaging high contrast dielectric distributions. The electrode geometry consists of two 4 x 4 parallel planes of copper conductors connected through custom built switch electronics to a commercially available capacitance to digital converter. Typical electrical capacitance tomography (ECT) systems rely solely on mutual capacitance readings to reconstruct images of dielectric distributions. This dissertation presents a method of reconstructing images of high contrast dielectric materials using only the self capacitance measurements. By constraining the unknown dielectric material to one of two values, the inverse problem is no longer ill-determined. Resolution becomes limited only by the accuracy and resolution of the measurement circuitry. Images were reconstructed using this method with both synthetic and real data acquired using an aluminum structure inserted at different positions within the sensing region. Comparisons with standard two dimensional ECT systems highlight the capabilities and limitations of the electronics and reconstruction algorithm.

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