13 research outputs found
Benchmarking study of Voltage and Current Source Inverter for Integrated Modular Motor Drives
No full textWith the adoption of Wide Band-gap (WBG) switches in Integrated Modular Motor Drives (IMMDs), the size of the drive is rapidly reduced with increase in efficiency and thermal performance. But with the advantages, use of WBG switches as a direct replacement for Si IGBT/MOSFET in Voltage Source Inverter (VSI) posses challenges in the field of steep dv /dt which leads to problems like over-voltage at motor terminal, degradation of cable and motor insulation leading to bearing current and EMI problems.Current Source Inverter (CSI) mitigates the problems associated with WBG usage in VSI but involves additional components like series SiC diodes leading to additional losses and temperature. This thesis explores design of VSI and CSI topology for High Speed Permanent Motor (HiSPEM) IMMD applications conducts bench-marking study of VSI an CSI based on efficiency and thermal performance of converters. .To begin with, VSI topology for IMMD modelled in PLECS with designing of control strategy. The loss model of SiC MOSFET used in VSI is simulated along with a lookup-table loss model for fast thermal performance evaluation. The current response is verified with the experimental setup with the comparison of loss model and thermal model results.Subsequently, the CSI topology is modelled with designing of multi-loop control strategy. The decoupling of the D and Q axis is performed using feed-forward decoupling method. The calculation of output capacitor filter is performed based on the cutoff frequency. The stability and bandwidth of different controller in the multi-loop are evaluated using bode plot analysis. Later, the diode loss is modelled and a thermal model is constructed using loss lookup-table for both SiC MOSFETs and series SiC didoes.The VSI and CSI typologies are bench-marked against each other on parameters such as converter loss, efficiency and thermal performance revealing the optimum topology to use at different current ratings and switching frequencies.Electrical Engineerin
Modeling and Analysis of the Spread of Carrier Dependent Infectious Diseases with Environmental Effects
No full textModeling and analysis of the spread of carrier dependent infectious diseases with environmental effects
No full textIn this paper, SIS and SIRS models for carrier dependent infectious diseases with immigration are proposed and analyzed by considering effects of environmental and human population related factors which are conducive to the growth of carrier population. In the modeling process, the density of carrier population is governed by a general logistic model. Further, it is assumed that the growth rate per capita and the modified carrying capacity of carrier population increase as the human population density increases. In each case, it is shown that the spread of an infectious disease increases as the carrier population density increases and the disease becomes more endemic due to immigration
MATHEMATICAL MODELING AND ANALYSIS OF THE SPREAD OF CARRIER DEPENDENT INFECTIOUS DISEASES: EFFECTS OF CUMULATIVE DENSITY OF ENVIRONMENTAL FACTORS
No full textDevelopment of spintronics devices and Type 1 heterojunctions from graphene nanoribbon superlattices
Get PDFGraphene physics and edge effects have a substantial influence on the electronic structure of graphene based nanomaterials. In this work, a detailed investigation of the edge effects of graphene nanoribbon superlattices is implemented in order to guide the discovery, design, and development of novel electronic devices. Graphene nanoribbon superlattices are low-dimensional carbon materials that are formed on making junctions with different graphene nanoribbons as components. This leads to a variety of interesting properties as the component ribbons have differing band structures, and edge effects lead to interesting physical applications.
Using Density Functional Theory (DFT), we calculate quasiparticle bandgaps, projected density of states and other electronic structure properties to find that based on the superlattice topology, we can form Type 1 heterojunctions and materials with applications in spintronics. These results were used in conjunction with a nearest-neighbor tight-binding approach to differentiate between three structures formed from graphene nanoribbon superlattices with different interface regions. It was found that slight variations in the interface configuration and structure can result in Type 1 heterojunctions whose behavior could be predicted from a simple 1D effective mass model, or devices with localized magnetism at the interface sites with potential applications in spintronics.
For devices with magnetic interfaces, we show the possibility of forming ferrimagnetic and anti-ferromagnetic materials systems and their possible application areas. We also explain the trends in total and absolute magnetism for these superlattice as parameters of the system considered.Item withdrawn by Mark Zulauf ([email protected]) on 2013-07-12T18:53:26Z
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University of Illinois Theses & Dissertations (ID: 1)
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Release Date: 2015-08-22 11:57:26 UTC
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemItem marked as restricted to the 'Administrator' Group (id=1) by Seth Robbins ([email protected]) on 2013-08-22T16:57:30Z
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Effects of habitat characteristics on the growth of carrier population leading to increased spread of typhoid fever: A model
No full textAbstractIn this paper, a non-linear model is proposed and analyzed to study the effects of habitat characteristics favoring logistically growing carrier population leading to increased spread of typhoid fever. It is assumed that the cumulative density of habitat characteristics and the density of carrier population are governed by logistic models; the growth rate of the former increases as the density of human population increases. The model is analyzed by stability theory of differential equations and computer simulation. The analysis shows that as the density of the infective carrier population increases due to habitat characteristics, the spread of typhoid fever increases in comparison with the case without such factors
Optical study of stress hormone‐induced nanoscale structural alteration in brain using partial wave spectroscopic microscopy
No full textQuantitative analysis of nanoscale intranuclear structural alterations in hippocampal cells in chronic alcoholism via transmission electron microscopy imaging
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