Electrical and Computer Engineering Commons^™

A Generalized Inverter Control Method For A Variable Speed Wind Power System Under Unbalanced Operating Conditions, Shuang Wu

ETD Archive

This thesis presents a generalized control method for complete harmonic elimination and adjustable power factor of a grid side inverter under unbalanced operating conditions used in variable speed wind power systems. The theoretical analysis of the proposed control method is described and verified by simulation in Simulink®. Two types of traditional control methods are also explained and applied in the wind power system for comparison, which are the indirect current control in a-b-c reference frame and the active and reactive power control in d-q synchronous frame. This method is verified for the gird fault right-through operation as well

Dc-Dc Power Converter Design For Application In Welding Power Source For The Retail Market, Edward J. Oshaben

ETD Archive

The purpose of this study is to design and analyze a DC-DC power converter for application in a welding power source that is cost-competitive with the more traditional, lower-tech welding power source topologies. This thesis first presents a background study of recent design approaches to DC-DC power converters, as they relate to application in welding power converters. The background study also surveys recent design approaches to welding power source controls. Evaluation of available options in DC-DC converter topologies and switching schemes for application in a welding power source is presented. Design methodology of a low-cost DC-DC converter for application in …

Experimental Study Of Cooperative Communication Using Software Defined Radios, Murali Krishna Marunganti

ETD Archive

The aim of this thesis is to implement and test a real time wireless communication environment. Cooperative Communication is one of the methods by which a reliable communication can be obtained. This is performed using a Software Defined Radio. The received output is compared with the actual signal that is transmitted over the wireless channel. The wireless communications are often hindered by the noisy environments and make the system unreliable. The interference from neighboring nodes also poses a major disadvantage. There is a necessity to improve the performance of the system where the neighbor nodes can work in coordination with …

Computational Complexity Of Signal Processing Functions In Software Radio, Kushal Y. Shah

ETD Archive

The increased usage of mobile communication devices has imposed a challenge of achieving efficient communication with minimum power consumption. Moreover, with the advent of software defined radios (SDR), it is highly possible that signal processing functions would be implemented in software in future mobile devices. Hence, the power consumption of these future devices will be directly related to the power consumed by the processor that executes SDR software. This thesis aims at analyzing the computational complexity of different modulation schemes and signal processing communication functions of IEEE WiFi standard. This analysis provides good insight on how the computational load varies …

Dynamics And Control Of An Electric Power Assist Steering System, Prasanth Babu Kandula

ETD Archive

In this thesis an Active Disturbance Rejection Controller (ADRC) is applied to Electrical Power Assist Steering (EPAS) system which assists the driver in steering the steering wheel of an automobile. Our control objective is to reduce the steering torque exerted by a driver, so that good steering feel of the driver will be achieved in the presence of external disturbances and system uncertainties which are very common in the EPAS system. The robustness and stability of ADRC controlled EPAS system is investigated through frequency-domain analyses. The Bode diagrams and stability margins demonstrate that the control system is stable during the …

Sensing And Control Of Mems Accelerometers Using Kalman Filter, Kai Zhang

ETD Archive

Surface micromachined low-capacitance MEMS capacitive accelerometers which integrated CMOS readout circuit generally have a noise above 0.02g. Force-to-rebalance feedback control that is commonly used in MEMS accelerometers can improve the performances of accelerometers such as increasing their stability, bandwidth and dynamic range. However, the controller also increases the noise floor. There are two major sources of the noise in MEMS accelerometer. They are electronic noise from the CMOS readout circuit and thermal-mechanical Brownian noise caused by damping. Kalman filter is an effective solution to the problem of reducing the effects of the noises through estimating and canceling the states contaminated …

Statistics Of The Received Power For Free Space Optical Channels, Stephen D. Lyke

Dissertations, Master's Theses and Master's Reports - Open

Free space optical (FSO) communication links can experience extreme signal degradation due to atmospheric turbulence induced spatial and temporal irradiance fuctuations (scintillation) in the laser wavefront. In addition, turbulence can cause the laser beam centroid to wander resulting in power fading, and sometimes complete loss of the signal. Spreading of the laser beam and jitter are also artifacts of atmospheric turbulence. To accurately predict the signal fading that occurs in a laser communication system and to get a true picture of how this affects crucial performance parameters like bit error rate (BER) it is important to analyze the probability density …

Discrete Coordinate Transformation For Designing All-Dielectric Flat Antennas, Wenxuan Tang, Christos Argyropoulos, Efthymios Kallos, Wei Song, Yang Hao

Department of Electrical and Computer Engineering: Faculty Publications

Transformation electromagnetics provides a practical approach to control electromagnetic fields at will. Based on this principle, novel devices such as the invisible cloak have been proposed. Here we examine the extension of this technique as applied to the design of flat devices in antenna systems. A method using discrete coordinate transformation is proposed, which allows the conversion of conventional devices with curved shapes into flat systems, while preserving their non-dispersive, isotropic, broadband, and lossless properties. Two specific design examples, a flat reflector and a flat lens embedded in free space, are presented. To avoid the loss and narrow bandwidth issues …

Clustering Of Protein Families Into Functional Subtypes Using Relative Complexity Measure With Reduced Amino Acid Alphabets, Aydin Albayrak, Hasan H. Otu, Ugur O. Sezerman

Department of Electrical and Computer Engineering: Faculty Publications

Background: Phylogenetic analysis can be used to divide a protein family into subfamilies in the absence of experimental information. Most phylogenetic analysis methods utilize multiple alignment of sequences and are based on an evolutionary model. However, multiple alignment is not an automated procedure and requires human intervention to maintain alignment integrity and to produce phylogenies consistent with the functional splits in underlying sequences. To address this problem, we propose to use the alignment-free Relative Complexity Measure (RCM) combined with reduced amino acid alphabets to cluster protein families into functional subtypes purely on sequence criteria. Comparison with an alignment-based approach was …

Bioinformatic Identification And Characterization Of Human Endothelial Cell-Restricted Genes, Manoj Bhasin, Lei Yuan, Derin B. Keskin, Hasan H. Otu, Towia A. Libermann, Peter Oettgen

Department of Electrical and Computer Engineering: Faculty Publications

Background: In this study, we used a systematic bioinformatics analysis approach to elucidate genes that exhibit an endothelial cell (EC) restricted expression pattern, and began to define their regulation, tissue distribution, and potential biological role.

Results:Using a high throughput microarray platform, a primary set of 1,191 transcripts that are enriched in different primary ECs compared to non-ECs was identified (LCB >3, FDR

Conclusion: The study provides an initial catalogue of EC-restricted genes most of which are ubiquitously expressed in different endothelial cells.

Magneto-Optical Properties Of Cobalt Slanted Columnar Thin Films, Daniel Schmidt, Tino Hofmann, Craig M. Herzinger, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Magneto-optical properties of ferromagnetic slanted columnar thin films from cobalt made by electron-beam glancing angle deposition are reported. Magneto-optic ellipsometry in the polar Kerr effect configuration was employed to determine the field- and wavelength-dependent complex magneto-optic polarizability parameter within the spectral range from 0.74 to 3.0 eV. Kerr effect measurements and calculations reveal a strong azimuthal dependence for the incident linear polarization with peak Kerr rotation one order of magnitude larger than what has been reported for solid Co thin films.

Non-Destructiveapproachto Ellipsometric Monitoring Of A Film Coating On The Inner Surface Of A Tube Shaped Sample, Gregory K. Prilbil, John A. Woollam, Martin M. Liphardt, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is the use of a focused electromagnetic beam which is caused to impinge on the top surface of a tube shaped sample, to investigate a film coating on inner surface during fabrication thereof and/or thereafter.

Real Time Location Tool For Precision Tracking Of Passive Uhf Rfid Tags In Two Dimensions, Nasir Kenarangui

Electrical Engineering Theses - Archive

This thesis addresses this problem of a precise RTLS (Real Time Location System) by implementing a Passive UHF RFID system. A software is created that connects to an RFID reader and accesses it's functionality to collect the tag's backscatter power which is the RSSI (Received Signal Strength Indicator), and the tag's ID. The software also connects with a web camera, and locates the tags within the camera's point of view by using only the RSSI of the tag. This software is capable of computing the locations of tags by locking on each tag's unique EPC, and marking their location and …

Optimization Of Phev Charging Station, Feiran Huang

Electrical Engineering Theses - Archive

Plug-in hybrid vehicles are the most feasible approach towards significantly lowering the consumption of oil and improve fuel economy with today's existing technology. In Electric Power Research Institute and the Natural Resources Defense Council (EPRI-NRDC) 2007 study already proved that PHEVs will reduce emissions if they are broadly adopted. However, the charging infrastructures/station become key factor in the success of prevail of PHEVs.The research of this paper is focusing the operation of the PHEV charging station with battery storage units. The battery units conserve the low price clean energy and discharge when demanded. The on-site installed photovoltaic (PV) and off-site …

Predition Of Torque And Radial Forces In Permanent Magnet Synchronous Machines Using Field Reconstruction Method, Banharn Sutthiphornsombat

Electrical Engineering Theses - Archive

Due to their high torque-to-loss ratio, permanent magnet synchronous machines (PMSM) have received increasing attention in automotive applications over the past decade. Because of this unique characteristics, many applications have utilized PMSM. In addition to high efficiency, quiet operation of the machines is desirable in automotive, naval and military applications. In order to operate at high efficiency quietly, the torque pulsation or torque ripple needs to be monitored and mitigated accurately. Magnitude of the torque ripple is influenced by the magnetic design (cogging torque) and excitation, and the pattern of ripple is affected by the machine's geometry (stator slots).Field reconstruction …

Convert Uhf Rfid Tag From Passive To Semi-Passive Tag Using External Power Sources, Tanvi Mehta

Electrical Engineering Theses - Archive

In this thesis, I present novel circuit designs that convert a passive radio frequency identification (RFID) tag into a semi-passive RFID tag. Passive RFID tags are relatively inexpensive to purchase and to integrate into objects and devices. However, in some environments and on some objects the performance of the pure passive tags is not sufficient for the intended applications. A semi-passive tag, in comparison to a pure passive tag, has significantly greater communication range since the semi-passive tag derives its operational power from an on-tag power source instead of just from an interrogator's communication signal. As a result, semi-passive tags …

Tutorial On Functionality And Performance Of Uu Link (Air Interface) Of Lte System, Prashant Srivastava

Electrical Engineering Theses - Archive

In this thesis we have discussed about the air interface for LTE. We have shown the extensive details of the two different types of access that is downlink access- Orthogonal frequency multiple access (OFDMA) and uplink access- Single carrier frequency division multiple access (SC-FDMA).We started with basic concepts about these techniques and proceeded ahead by discussing the operation and design of both types of methods. Also we have shown the transmission chain for downlink and uplink showing step by step that how the data and control information are transmitted over air in LTE. We have presented a brief overview of …

Optimal Output Gain Algorithm For Feed-Forward Network Training, Babu Hemanth Kumar Aswathappa

Electrical Engineering Theses - Archive

A batch training algorithm for feed-forward networks is proposed which uses Newton's method to estimate a vector of optimal scaling factors for output errors in the network. Using this vector, backpropagation is used to modify weights feeding into the hidden units. Linear equations are then solved for the network's output weights. Elements of the new method's Gauss-Newton Hessian matrix are shown to be weighted sums of elements from the total network's Hessian. The effect of output transformation on training a feed-forward network is reviewed and explained, using the concept of equivalent networks. In several examples, the new method performs better …

Improved Classification In Flat Networks, Madhu Gannapal

Electrical Engineering Theses - Archive

It is shown that optimal flat networks can be found as solutions to least squares problems. An algorithm is presented to improve existing classifier training methods by changing the desired outputs. The algorithm is based on minimum probability of error. The algorithm's performance is compared with those of other algorithms including the Bayes Gaussian classifier. The Convergence of training and the effects of outliers are analyzed in all the algorithms presented here.

A Tutorial On The Functionality On Core Network Mobility, Jatinder Jasbir Singh

Electrical Engineering Theses - Archive

Long Term Evolution (LTE) is next generation Mobile Broadband Technology, which promises to offer significantly higher data rates, better quality, and more economical. Many of the service providers are planning to offer this service by 2010-2012. LTE is vast change in the telecommunication industry from circuit switched network to packet switched network and now all IP-network. In the fast changing mobile telecommunications seamless handover is important for any technology to succeed. It is desirable and beneficial from operator as well as user perspective to have seamless handover with cost effectiveness, enhanced features, and location independence not only in the case …