Power and Energy Commons^™

On The Radius Of Convergence Of Interconnected Analytic Nonlinear Input-Output Systems, Makhin Thitsa, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

A complete analysis is presented of the radii of convergence of the parallel, product, cascade and feedback interconnections of analytic nonlinear input-output systems represented as Fliess operators. Such operators are described by convergent functional series, which are indexed by words over a noncommutative alphabet. Their generating series are therefore specified in terms of noncommutative formal power series. Given growth conditions for the coefficients of the generating series for the subsystems, the radius of convergence of each interconnected system is computed assuming the subsystems are either all locally convergent or all globally convergent. In the process of deriving the radius of …

In Situ And Ex Situ Studies Of Molybdenum Thin Films Deposited By Rf And Dc Magnetron Sputtering As A Back Contact For Cigs Solar Cells, K. P. Aryal, H. Khatri, R. W. Collins, S. Marsillac

Electrical & Computer Engineering Faculty Publications

Molybdenum thin films were deposited by rf and dc magnetron sputtering and their properties analyzed with regards to their potential application as a back contact for CIGS solar cells. It is shown that both types of films tend to transition from tensile to compressive strain when the deposition pressure increases, while the conductivity and the grain size decreas. The nucleation of the films characterized by in situ and real time spectroscopic ellipsometry shows that both films follow a Volmer-Weber growth, with a higher surface roughness and lower deposition rate for the rf deposited films. The electronic relaxation time was then …

Fuzzy Interference System In Energy Demand Prediction, Thair Mahmoud, Daryoush Habibi, Octavian Bass, Stefan Lachowicz

Research outputs 2012

No abstract available.

Measuring And Filtering Microwave Radiations Using Frequency Selective Surface Through Energy Saving Glass, Irfan Ullah

Theses: Doctorates and Masters

This thesis presents the results of our investigation into the measurement and filtering of microwave radiation, and the subsequent development of a microwave reduction solution for modern building architecture utilising Energy Saving Glass (ESG), in conjunction with Frequency Selective (FSS) surfaces through which useful signals can be filtered. In the investigation, radiation power density levels arising from the three common microwave sources (radio base stations, mobile phones, and microwave ovens) were measured, and the results were compared with the standards provided by the Australian Radiation Protection and Nuclear Safety Agency. For the radio base stations, the relationship between radiation intensity …

Modeling And Analysis Of Grid-Connected Solar-Wind Hybrid Power System, Sultan Altamimi

Dissertations and Theses @ UNI

Renewable energies are considered to be a significant part of the energy mix to assist the existing electricity demand and the future of electrical generation. Electrical power simulation software is increasingly being used to answer and determine the source of potential problems in the actual power system. To have a better understanding of an electrical power system, it is essential to validate all the components through simulation within an environment that allows accurate modeling of all power system components. This research presents modeling and analysis of an actual grid-connected solar-wind hybrid system at University of Northern Iowa campus in Cedar …

Distributed Solar Photovoltaic Grid Integration System : A Case Study For Performance, Ming Shen

Dissertations and Theses

The needs to the sustainable development of electricity, energy efficiency improvement, and environment pollution reduction have favored the development of distributed generation (DG). But the problems come with increasing DG penetration in distribution networks. This thesis presents the Solar Energy Grid Integration System (SEGIS) Stage III project done by Portland General Electric (PGE), Advanced Energy, Sandia National Lab on a PGE selected distribution feeder. The feeder has six monitored commercial solar PV systems connected. The total power output from the PV systems has the potential to reach 30% of the feeder load. The author analyzes the performance of the solar …

The Integration Of Wind Energy In The Electrical Grid During The Contingencies, Islam Ali

Dissertations and Theses @ UNI

As wind energy expansion develops, there are also many problems and challenges to connect the wind farms to the grid. There are many different interactions during the connection like the voltage flicker, harmonics, transient, short circuit current, frequency, and safety protection. Those problems may affect the performance of the grid and may cause serious problems. This study investigates the grid-connection problems for the wind turbines and offers appropriate solutions. This study provides a simulation for the power system during the faults. The electrical grid in the simulation contains generators and wind turbines which are connected to the grid. It also …

Adaptive Mitigation In The Electric Power Sector, Lesley K. Mcallister

BYU Law Review

No abstract provided.

Identification Of Power System Stability Using Relevant Modes, Rogers Whitlock Jr

LSU New Orleans Theses and Dissertations

The purpose of this investigation is to identify appropriate location of capacitor banks and sources of reactive power by studying power system stability in the vicinity of system equilibrium states. The locations for reactive power sources are determined by identifying those modes of the system that participate most in the system behavior in general and in dictating the final state of the system after experiencing faults or disturbances. To identify the relevant modes of the system that participate most in the system dynamic, we shall make use of modal and participation analysis for different system conditions. We also apply modal …

Lithium-Based Battery System Management And Balancing, William Joel Schmidt Iii

Purdue Polytechnic Masters Theses

This thesis builds upon previous work completed for the design and evaluation of active lithium battery system management. Simulations were performed to provide a comparison for the hardware that was designed, built, and tested. An analysis of the simulation and hardware results was completed to support or disprove the initial hypothesis. A DC-DC converter was used as the source for the balancing current. Lithium polymer batteries with a 5Ah capacity were used for testing the designed hardware. The findings showed that there is a reduction in the system voltage swing during balancing as well as less time taken to decrease …

Integration Of Upqc For Power Quality Improvement In Distributed Generation Network – A Review, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon

Conference Papers

In this paper a technical review of the integration of a Unified Power Quality Conditioner (UPQC) in a distributed generation network is presented. Although the primary task of UPQC is to minimize grid voltage and load current disturbances along with reactive and harmonic power compensation, additional functionalities such as compensation of voltage interruption and active power transfer to the load and grid have also been identified. Connection methodologies with their advantages and disadvantages are also described. Recent improvements in capacity expansion techniques and future trends for the application of UPQC in distributed modes are also identified.

Highly Efficient Maximum Power Point Tracking Using A Quasi-Double-Boost Dc/Dc Converter For Photovoltaic Systems, Christopher J. Lohmeier

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Solar photovoltaic (PV) panels are a great source of renewable energy generation. The biggest problem with solar systems is relatively low efficiency and high cost. This work hopes to alleviate this problem by using novel power electronic converter and control designs. An electronic DC/DC converter, called “Quasi-Double-Boost DC/DC Converter,” is designed for a Solar PV system. A Maximum Power Point Tracking (MTTP) algorithm is implemented through this converter. This algorithm allows the PV system to work at its highest efficiency. Different current sensing and sensorless technologies used with the converter for the MPPT algorithm are offered and tested. Design aspects …

Digitally Controlled, Modular Electronic Load, Jason L. March

Master's Theses

This project entails the design and development of a digitally controlled, modular electronic load. The proposed load is unique from existing designs because it has the added ability to increase its maximum current level by adding identical modules in parallel. Each module is designed to sink a maximum of 5A at 60V but more modules allow for more current. The cost and simplicity of the design are considered such that it can be reproduced in-house to replace, whenever possible, the resistor box for load testing of any analog circuits but more specifically power electronic circuits.

The design process as well …

Fabrication Of Composite Nanomaterials For Thin Film Amorphous Silicon Solar Cells, Benjamin Seth Newton

Graduate Theses and Dissertations

A material with the precise combination of amorphous silicon and polycrystalline silicon would be able to take advantage of the high absorption capabilities of amorphous silicon and the electron transport capabilities of polycrystalline silicon. Polycrystalline nanostructures in the form of wires can also take advantage of other properties of light absorption, trapping and scattering inherent in nanowire structures. These properties of high absorption and electron transport in one device would lead to advances in the search for highly efficient low cost solar cells and sensors. In this work a thin film material composed of an array of polycrystalline silicon nanostructures …

Modeling And Analysis Of A Four-Switch Buck-Boost Dynamic Capacitor, Oscar Plasencia

Master's Theses

Modern electric power utilities are facing a variety of challenges introduced by the increasing complexity of their operation, structure, and consumer loads. One such challenge has been to supply the ever growing demand for reactive power which is essential for grid support. For this reason dynamic VAR technologies are becoming much more important to modern day power systems. A recent dynamic VAR technology known as the Dynamic Capacitor offers full quadrant capacitive VAR control through the combination of AC/AC buck and boost cells. This paper introduces a new topology deemed the “Four-Switch Buck-Boost Dynamic Capacitor” which promises to combine the …

Energy-Based Analysis Of Utility Scale Hybrid Power Systems, Kwame Agyenim-Boateng

UNLV Theses, Dissertations, Professional Papers, and Capstones

The promise of large-scale use of renewables such as wind and solar for supplying electrical power is tempered by the sources' transient behavior and the impact this would have on the operation of the grid. Among the methods cited for addressing some of those concerns are exploring the complementary nature of solar and wind power generation, and through the use of supplemental energy storage. While the technology for the latter has not been proven to be economical on a large scale at the present time, some assessments of what magnitude is required can be made. An energy-based analysis of utility …

Matlab/Simulink Implementation And Analysis Of Three Pulse-Width-Modulation (Pwm) Techniques, Phuong Hue Tran

Boise State University Theses and Dissertations

With advances in solid-state power electronic devices and microprocessors, various pulse-width-modulation (PWM) techniques have been developed for industrial applications. For example, PWM-based three-phase voltage source inverters (VSI) convert DC power to AC power with variable voltage magnitude and variable frequency.

This thesis discusses the advantages and drawbacks of three different PWM techniques: the sinusoidalPWM(SPWM) technique, the third-harmonic-injection PWM(THIPWM) technique, and the space-vector PWM (SVPWM) technique. These three methods are compared by discussing their ease of implementation and by analyzing the output harmonic spectra of various output voltages (poles voltages, line-to-neutral voltages, and line-to-line voltages) and their total harmonic distortion (THD). …

In-Situ Ellipsometry Characterization Of Anodically Grown Silicon Dioxide And Lithium Intercalation Into Silicon, Eric A. Montgomery

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, in-situ ellipsometry and electroanalytical investigations of two electrochemical processes are reported: including the formation of anodically grown silicon dioxide and the intercalation of lithium into silicon. Analysis of the ellipsometry data shows that the anodically grown silicon dioxide layer is uniform and has similar properties as thermally grown silicon dioxide. The lithium-ion intercalation data reveals non-uniform thin film formation, which requires further studies and development of appropriate ellipsometric optical models.

Advisers: Eva Schubert and Mathias Schubert

Preparation And Application Of Nano-Nio As Anode In Lithium-Ion Batteries, Cheng-Dong Bai, Jia-Jia Chen, Qi Zhang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

In this work, the nano-NiO material was prepared by hydrothermal method. The surface morphologies and electrochemical properties of nano-NiO material were investigated. The special nano-NiO material with porous surface assembling honeycombs(100-200nm) was obtained by using surface active agents. The discharge capacity of nano-NiO electrode up to 2385.7 mAh/g was achieved at current density of 0.1A/g in the first circle,while 1100mAh/g could be maintained after 100 circles. At current density of 2.0A/g, the discharge capacity of 600 mAh/g was obtained. And when the current density was reduced to 0.1A/g, the discharge capacity was restored to 1050 mAh/g. The nano-NiO electrode exhibited …

Microemulsion Preparation And Electrochemical Characterization Of Pt/C, Ptir/C Electrocatalysts, Ya-Ping Zeng, Sheng Sui

Journal of Electrochemistry

The Pt/C electrocatalysts were prepared by three different systems and the PtIr/C electrocatalysts were prepared with four different Ir contents. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), cyclic voltammetry (CV), potentiostatic and potentiodynamic polarizations measurements. The experimental results confirmed that the electrocatalyst particles prepared by the microemulsion method were well distributed on XC-72R supports with the active particle sizes of 5～10nm and good electrocatalysts activity. The Pt85Ir15/C electrocatalysts showed the highest overall electrochemical activity in unitized regenerative fuel cell.