Electrical and Computer Engineering Commons^™

Feedback Linearization Internal Control For The Unified Power Flow Controller, Keyou Wang, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents feedback linearization-based controller design methodology for a unified power flow controller (UPFC) to achieve rapid reference signal tracking in the internal level. Feedback linearization control (FBLC) is a nonlinear technique based on differential geometry theory and overcomes the drawback of traditional PI control linearizing at one specific operating condition. FBLC is applied on UPFC dynamic model via an appropriate coordinate transformation and LQR control is then applied on the transferred linear system. the proposed control is validated on the IEEE 118-bus system with full-order generator and network models. ©2010 IEEE.

Education For Renewable Electric Energy Delivery And Management Systems, Mariesa Crow, M. Baran, A. Q. Huang

Electrical and Computer Engineering Faculty Research & Creative Works

The Future Renewable Electric Energy Delivery and Management (FREEDM) Systems Center is a National Science Foundation (NSF) Generation-III Engineering Research Center (ERC) established in 2008 with the mission to develop the fundamental and enabling technologies necessary for a new and paradigm shifting power grid infrastructure, the FREEDM System. the center involves more than fifty professors and one hundred fifty graduate and undergraduate students from five US universities and two international universities, as well as more than sixty companies and national laboratories in 28 states and nine countries. This paper will discuss some of the on-going efforts to educate students to …

Optimal Tuning Of System Stabilizer Parameters Using Pbil With Adaptive Learning Rate, K. A. Folly, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an optimal tuning of Power System Stabilizers (PSS) for a multi-machine power system using Population-Based Incremental Learning (PBIL) algorithm with adaptive learning rate. the proposed (APBIL) algorithm can adjust the learning rate automatically according to the degree of evolution of the search. the objective of the design is to achieve adequate stability over a wide range of operating conditions. the proposed controller is compared with traditional PBIL with fixed learning rate (PBIL) and tested under various operating conditions. Simulation results show that the APBIL based PSS provides a more efficient search capability and gives a better damping …

Voltage Prediction Using A Cellular Network, Lisa L. Grant, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Better identification tools are needed for power system voltage profile prediction. the power systems of the future will see an increase in both renewable energy sources and load demand increasing the need for quick estimation of bus voltages and line power flows for system security and contingency analysis. a Cellular Simultaneous Recurrent Neural Network (CSRN) to identify and predict bus voltage dynamics is presented in this paper. the benefit of using a cellular structure over traditional neural network architectures is that the network can represent a direct mapping of any power system allowing for easier scalability to large power systems. …

Gms Considering Uncertainty In Wind Power In A Wind-Hydrothermal Power System, Y. Yare, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

An optimal preventive generator maintenance scheduling (GMS) in a smart grid environment comprising wind-hydrothermal energy resources is presented in this paper. GMS problem is solved with the aim of maximizing economic benefits subject to satisfying system constraints. This GMS formulation becomes a challenging problem because of the variability and intermittency of wind speed and the incorporation of uncertainty in wind generation. the objective is to perform preventive GMS in such a manner that the annual generation cost is minimized, the annual cost saving is increased while all operating constraints are satisfied in the presence of uncertainty in wind generation. Discrete …

Embedded Radio Frequency Identification Device License Plates For Roadside Use In Nebraska, Dwight L. Mosby Jr.

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The transportation industry has many stakeholders with different needs that work with advanced technologies. Radio Frequency Identification (RFID) is an emerging technology that is used to track inventory and it holds promise for the transportation industry. This research identifies how to evaluate transportation stakeholder requirements for RFID technologies using a tool described as the House of Quality (HOQ). This research investigates RFID’s ability to work in license plates and may provide infrastructure to support identifying RFID enabled commercial vehicles. This research considers variables that affect the performance of a RFID License Plate System that will use a scanner located at …

Nanofabrication Of Surface-Enhanced Raman Scattering Device By An Integrated Block-Copolymer And Nanoimprint Lithography Method, E. L. Yang, C. C. Liu, C. Y.P. Yang, P. F. Nealey, C. A. Steinhaus, Jack L. Skinner

Mechanical Engineering

The integration of block-copolymers and nanoimprint lithography presents a novel and cost-effective approach to achieving nanoscale patterning capabilities. The authors demonstrate the fabrication of a surface-enhanced Raman scattering device using templates created by the block-copolymers nanoimprint lithography integrated method.

Subwoofer Frequency Response Optimization By Means Of Active Control, Luis Dominguez

Aerospace Engineering

Most subwoofer systems have difficulties producing frequencies in the low end of the hearing spectrum due to the added power requirements and instabilities. Active controls can transform the audio signal without changing physical characteristics and ultimately generating a more impressive audio system. A Linkwitz transform crossover was implemented to extend the low end frequency response of a sealed enclosure. A graphical user interface in MATLAB was written to aid in selection of components, driver and enclosure volume. The circuit board was built and integrated with a home theater system inside of a couch and tested with a Real Time Analyzer. …

On The Solution Of A Class Of Large Body Problems With Full Or Partial Circular Symmetry By Using The Finite-Difference Time-Domain (Fdtd) Method, Wenhua Yu, Dean Arakaki, Raj Mittra

Electrical Engineering

This paper presents an efficient method to accurately solve large body scattering problems with partial circular symmetry. The method effectively reduces the computational domain from three to two dimensions by using the reciprocity theorem. It does so by dividing the problem into two parts: a larger 3-D region with circular symmetry, and a smaller 2-D region without circular symmetry. An finite-difference time-domain (FDTD) algorithm is used to analyze the circularly symmetric 3-D case, while a method of moments (MoM) code is employed for the nonsymmetric part of the structure. The results of these simulations are combined via the reciprocity theorem …

Architecture, Modeling, And Analysis Of A Plasma Impedance Probe, Magathi Jayaram

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variations in ionospheric plasma density can cause large amplitude and phase changes in the radio waves passing through this region. Ionospheric weather can have detrimental effects on several communication systems, including radars, navigation systems such as the Global Positioning Sytem (GPS), and high-frequency communications. As a result, creating models of the ionospheric density is of paramount interest to scientists working in the field of satellite communication.

Numerous empirical and theoretical models have been developed to study the upper atmosphere climatology and weather. Multiple measurements of plasma density over a region are of marked importance while creating these models. The lack …

Universality Of Non-Ohmic Shunt Leakage In Thin-Film Solar Cells, Sourabh Dongaonkar, Jonathan D. Servaites, Grayson M. Ford, Stephen Loser, James E. Moore, Ryan M. Gelfand, Hooman Mohseni, Hugh W. Hillhouse, Rakesh Agrawal, Mark A. Ratner, Tobin J. Marks, Mark Lundstrom, Muhammad A. Alam

Birck and NCN Publications

We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se₂ (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V< ∼ 0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (I_sh), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V = 0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from …

Control Of Longitudinal Pitch Rate As Aircraft Center Of Gravity Changes, John Andres Cadwell Jr.

Master's Theses

In order for an aircraft to remain in stable flight, the center of gravity (CG) of an aircraft must be located in front of the center of lift (CL). As the center of gravity moves rearward, pitch stability decreases and the sensitivity to control input increases. This increase in sensitivity is known as pitch gain variance. Minimizing the pitch gain variance results in an aircraft with consistent handling characteristics across a broad range of center of gravity locations.

This thesis focuses on the development and testing of an open loop computer simulation model and a closed loop control system to …

Modeling Of A Gyro-Stabilized Helicopter Camera System Using Neural Networks, Nicholas Joseph Layshot

Master's Theses

On-board gimbal systems for camera stabilization in helicopters are typically based on linear models. Such models, however, are inaccurate due to system nonlinearities and complexities. As an alternative approach, artificial neural networks can provide a more accurate model of the gimbal system based on their non-linear mapping and generalization capabilities.

This thesis investigates the applications of artificial neural networks to model the inertial characteristics (on the azimuth axis) of the inner gimbal in a gyro-stabilized multi-gimbal system. The neural network is trained with time-domain data obtained from gyro rate sensors of an actual camera system. The network performance is evaluated …

College Of Engineering Senior Design Competition Fall 2010, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Model-Based Analysis Of Electric Drive Options For Medium-Duty Parcel Delivery Vehicles, Robb A. Barnitt, Aaron D. Brooker, Laurie Ramroth

Publications (T)

Medium-duty vehicles are used in a broad array of fleet applications, including parcel delivery. These vehicles are excellent candidates for electric drive applications due to their transient-intensive duty cycles, operation in densely populated areas, and relatively high fuel consumption and emissions. The National Renewable Energy Laboratory (NREL) conducted a robust assessment of parcel delivery routes and completed a model-based techno-economic analysis of hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle (PHEV) configurations. First, NREL characterized parcel delivery vehicle usage patterns, most notably daily distance driven and drive-cycle intensity. Second, drive-cycle analysis results framed the selection of drive cycles used …

A Fiber Bragg Grating-Based All-Fiber Sensing Systems For Telerobotic Cutting Applications, Ginu Rajan, Dean Callaghan, Yuliya Semenova, Mark Mcgrath, Eugene Coyle, Gerald Farrell

Articles

A fiber Bragg grating (FBG)-based strain sensing system for minimally invasive telerobotic cutting applications is presented in this paper. Investigations assume that a scissor blade can be approximated as a uniformly tapered cantilever beam. A replica of the scissor blade is produced and strain characterization has been carried out using an FBG sensor system. Results are validated against measurements obtained using conventional electrical resistance strain gauges. The scissor blade experiences both direct and lateral forces during cutting, hence the system is characterized for a direct load range of 0-30 N and a lateral load range of 0-10 N. The results …

Modeling The Random Component Of Manufacturing Yield Of Integrated Circuits., David L. Farnsworth, Michael E. Long

Articles

A model is created for the number of integrated circuits that are good from each wafer on which they are fabricated. The goal is to separate the random or common cause loss from the systematic or special loss. The random loss from this type of process is modeled so that false alarms indicating systematic loss are less likely to occur and so that the structure of the systematic loss can be determined.

Offshore Wind Power Integration Into The South Carolina Power System, Mountaga Fane

All Theses

The steady state analysis of the impact of offshore wind on the South Carolina power transmission was conducted in three phases of incremental wind energy injection into the system using forecasted base power flow. The simulation of Phase I involved the generation capacity of 80 MW projected for 2014 in state water. The modeling Phases II and III, which will distribute the energy among neighboring utilities, involve a supplementary capacity of 1000 MW projected for 2020 and 2000 MW for 2030 in federal water. In addition to this steady state investigation, a contingency analysis was performed on the power system …

On The Use Of Natural-Mode Basis Functions For Electromagnetic Analysis Of Arbitrary Conducting Surfaces, Joshua Lawrence

All Theses

The natural modes defined in the singularity expansion method (SEM) are used as basis functions for the frequency- and time-domain current responses of arbitrary perfect electrically conducting (PEC) surfaces in this work. First, a method of determining the natural frequencies and corresponding modes which employs the electric field integral equation is presented. These quantities are then calculated for several geometries and the currents induced due to an incident plane wave in the frequency and time domains are approximated by a weighted sum of the natural modes. Additionally, the modal weights prescribed by SEM are compared to a set of weights …

Circuit Modules For Cmos High-Power Short Pulse Generators, Yongtao Geng

All Theses

High-power short electrical pulses are important for high-performance functionality integration, such as the development of microelectromechanical/nanoelectromechanical systems (MEMS/NEMS), system on chip (SoC) and lab on chip (LoC). Many of these applications need high-power (low impedance load) short electrical pulses, in addition to CMOS digital intelligence. Therefore, it is of great interest to develop new circuit techniques to generate high-power high-voltage short electrical pulses on-chip.
Results on pulse forming line (PFL) based CMOS pulse generator studies are reported. Through simulations, the effects of PFL length, switch speed and switch resistance on the output pulses are clarified. CMOS pulse generators are modeled …