Power and Energy Commons^™

Time-Varying Harmonic Analyzer Prototype, Diego F. Fabri, Carlos H. N. Martins, Leandro R. M. Silva, Carlos A. Duque

University Faculty Publications and Creative Works

This paper presents a time-varying harmonic analyzer based on the Sliding Window DFT implemented on a DSP platform. The harmonic decomposition is carried out using the TMS320F28027 digital signal processor, and the samples of the decomposed signal are sent to a PC based computer using serial interface. Several real cases are analyzed, revealing the time-varying behavior of the harmonic component. Different from commercial harmonic analyzer, the prototype presented in this paper uses a different way to visualize the harmonic components, based on time decomposition approach. This new visualization of time-varying harmonics might help engineers and researchers to develop new insights …

Time-Varying Harmonic Analyzer Prototype, Diego F. Fabri, Carlos H. N. Martins, Leandro R. M. Silva, Carlos A. Duque

University Faculty Publications and Creative Works

This paper presents a time-varying harmonic analyzer based on the Sliding Window DFT implemented on a DSP platform. The harmonic decomposition is carried out using the TMS320F28027 digital signal processor, and the samples of the decomposed signal are sent to a PC based computer using serial interface. Several real cases are analyzed, revealing the time-varying behavior of the harmonic component. Different from commercial harmonic analyzer, the prototype presented in this paper uses a different way to visualize the harmonic components, based on time decomposition approach. This new visualization of time-varying harmonics might help engineers and researchers to develop new insights …

Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue

Faculty Publications

Porous electrode is the critical component of solid-oxide fuel cells (SOFCs) and provides a functional material backbone for multi-physicochemical processes. Model based electrode designs could significantly improve SOFC performance. This task is usually performed via parameter studies for simple case and assumed property distributions for graded electrodes. When nonlinearly coupled multiparameters of electrodes are considered, it could be very difficult for the model based parameter study method to effectively and systematically search the design space. In this research, the optimization approach with a genetic algorithm is demonstrated for this purpose. An anode-supported proton conducting SOFC integrated with a fuel supply …

The Generation Of Domestic Electricity Load Profiles Through Markov Chain Modelling, Fintan Mcloughlin, Aidan Duffy, Michael Conlon

Articles

Micro-generation technologies such as photovoltaics and micro-wind power are becoming increasing popular among homeowners, mainly a result of policy support mechanisms helping to improve cost competiveness as compared to traditional fossil fuel generation. National government strategies to reduce electricity demand generated from fossil fuels and to meet European Union 20/20/20 targets is driving this change. However, the real performance of these technologies in a domestic setting is not often known as high time resolution models for domestic electricity load profiles are not readily available. As a result, projections in terms of reducing electricity demand and financial paybacks for these micro-generation …

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 …

Effect Of Impurities On Performance Of Proton Exchange Membrane Fuel Cell Components, Kitiya Hongsirikarn

All Dissertations

It is believed that proton–exchange membrane fuel cells (PEMFCs) are going to be exploited as power generation devices for stationary, automotive, and portable applications in the near future because of their high performance and environmental friendliness. Up to the present, wide spread utilization of PEMFCs is not viable because of their cost and durability in the presence of fuel and oxidant stream impurities. These impurities include NH₃, hydrocarbons, CO, CO₂, halogenated compounds, cations, etc. The objective of this research was to investigate the effect of these harmful contaminants containing in the H₂ fuel stream on …

Effects Of Cloud-Induced Photovoltaic Power Transients On Power System Protection, Joel A. Nelson

Master's Theses

As the world strives towards finding alternative sources of power generation, photovoltaic generation has become an increasingly prevalent alternative energy source on power systems world-wide. This paper studies the effects that incorporating photovoltaic generation has on the existing power systems and their power system protection schemes. Along with the addition of this emerging alternative energy source comes the volatility of PV power generation as cloud-cover produces erratic variations in solar irradiance and PV power production. Such variations in PV power may lead to unfavorable operating conditions and power system failures. The issues addressed in this paper include a study of …

Energy Efficient Led Displays, John Mani Kumar Jupalli

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this research work, an innovative pixel architecture RGBW, consisting of red (R), green (G), blue (B), and white (W) LEDs, is designed and implemented for color generation. Energy consumption of new pixel architecture consisting of RGBW LEDs is compared to standard architecture consisting of RGB LEDs. Human perception experiments are conducted to study the differences in perception between the two architectures when the same colors are generated using RGBW vs. RGB. Measurements of power for a 32inch x 16inch LED display has proved up to 18% power savings for low saturated colors, up to 8% for high saturated colors …

The Sol-Gel Synthesis And Electrochemical Performance Of Li3V2(Po4)3/C Cathode Material For Lithium Ion Battery, Li-Ying Liu, Lian Chen, Hai-Yan Zhang, Yu-Chun Zhai

Journal of Electrochemistry

Li₃V₂(PO₄)₃/C was synthesized by sol-gel method with citric acid as chelate and C sources. Physical and electrochemical performances of as-prepared materials were characterized through XRD, SEM and galvanostatic charge-discharge tests,etc. The results showed that products produced by calcining at 800 ℃ for 12 h had a single phase crystal structure and relatively small particle sizes with uniform distribution. At 0.1 C, 0.5 C and 1 C, the initial specific discharge capacities were 153.0, 143.1 and 130.6 mAh·g^-1, respectively, and capacity efficiencies were 93.1%, 85.4% and 77.3% after 50 cycles, respectively. …

Photoelectrochemical Properties Of N, S, And Cl Modified Nano Tio2 Thin Films, Hong Yun, Chang-Jian Lin, Jing Li, Rong-Gui Du

Journal of Electrochemistry

The nitrogen(N),sulfur(S) and chlorine(Cl) modified nano TiO₂ thin films were prepared by adding Ti(O-n-Bu)₄ as the precursor into concentrated HNO₃,H₂SO₄ and HCl Solutions,respectively,on different substrates in a sol-gel process.The photoelectrochemical performances of N,S and Cl modified nano TiO₂ thin films have been studied by UV-vis(DRS),photocurrent curves,EIS and OCP-time curves.N-modified TiO₂ nano films show better surface structure,which helps to improve the quantum efficiency of nano TiO₂ thin films.

Hydrothermal Reduction Synthesis Of Lifepo4 And Its Electrochemical Performance, Hong-Li Zou, Guang-Hui Zhang, Pei-Kang Shen

Journal of Electrochemistry

The cathode materials of LiFePO₄ were prepared via a hydrothermal reduction method using FeCl₃ as Fe source and iron as a reducing agent.The results showed that ferric salt could be reduced to ferrous salt completely under the hydrothermal condition and pure-phase LiFePO₄ was obtained based on the test results of XRD and FTIR.Carbon-coated LiFePO₄ was synthesized by pyrolysisng glucose at high temperature.The morphologies of pure LiFePO₄ displayed cluster-like while the LiFePO₄/C displayed sphere-like particles.The electrochemical test showed that the LiFePO₄/C had good rate performance,while LiFePO₄ delivered much lower discharge capacity.

Effects Of Solvents And Electrolyte Salts On The Electrochemical Reduction Of Oxygen In Non-Aqueous Electrolytes, Yan-Yan Tian, Wei Wu, Jun Gao, Yong Yang

Journal of Electrochemistry

The electrochemical reduction processes of oxygen in different non-aqueous solvents such as acetonitrile(MeCN),propylene carbonate(PC) and their mixtures were investigated by cyclic voltammetry method.The results indicated a one electron reduction of oxygen to O^2-occured in these systems as a first step reduction,no matter whether in tetrabutylammonium hexafluorophosphate(TBAPF₆)/MeCN or TBAPF₆/PC electrolyte.However,the CV curves in 0.1 mol·L^-1 TBAPF₆/MeCN showed a couple of reversible redox peaks,indicating that the reduction process of oxygen was irreversible in the 0.1 mol·L^-1 TBAPF₆/PC electrolyte.In the PC-based electrolyte,the reduction current peak reduced largely and the oxidation peak …

Electrodeposition Of Lead Dioxide From Dluoroborate Solutions, Chun-Mei Kong, Yong-Ming Tang, Wen-Zhong Yang, Xiao-Yuan Yang

Journal of Electrochemistry

The PbO₂ anodes were prepared on platinum from fluoroborate media and its doped solutions by electrodeposition technique.Elecchemical and pysicochemical properties of these PbO₂ films were studied by cyclic voltammetry methods,XRD and SEM.The results showed that the presence of BF₄-increased PbO₂ electrodeposition rate;the prepared lead dioxide consisted of β-PbO₂;the preferential orientation of crystals and surface morphology were affected a lot by doping F-and Fe³⁺.The FB/F-Fe-PbO₂ electrode exhibited regular-shaped layers with compact morphology.Furthermore,increasing current density also change the preferential orientation of PbO₂ crystals.

Research On Nafion/Sio2 Composite Membrane In All Vanadium Redox Flow Battery, Dong-Dong Liu, Mao-Cai Lin, Tao Guan, Qing-Chun Yu

Journal of Electrochemistry

The Nafion117/SiO₂ composite membrane was prepared by sol-gel method.The results showed that,during composite membrane preparation process,the ratio of MeOH and TEOS did not affect the penetration rate of VO²⁺ basically,however,the lowest permeability of 427×10-9cm²/s in the membrane was achieved while hydrolysis time was 10 min and natural drying for 24 h after hydrolysis,which reduced by 52 times than that in Nafion117 membrane.The SEM tests proved that SiO₂ grains grew bigger in the composite membrane during the natural drying,and most of the holes in Nafion117 were filled.Single cell test showed the battery power efficiency was improved …

Energy Storage And Management For A Small Series Plug-In Hybrid Electric Vehicle, Liqin Ni

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

Plug-in hybrid electric vehicles (PHEVs) are gaining increasing interest for both residential and commercial transportation applications. In PHEV design, energy storage system (EES) is a critical component which will impact the overall design efficiency, performance, cost and etc. This dissertation aims to design an advanced energy storage system for a small plug-in hybrid electric vehicle, whose performance will approach very closely to the optimal possible, in terms of energy efficiency and acceleration, for passenger road vehicles application. Moreover, practical automotive requirements are considered during ESS design, such as cost, life time, safety and volume.

This dissertation utilizes ultracapacitors in conjunction …

Designing A Photovoltaic System Hybrid For A Health Clinic In Camilo Ortega, Nicaragua, Jeremy Holliman

Electrical Engineering

As developing nations continue to foster the development of their technologies and economies, industrialized nations have taken an active approach in providing green and sustainable alternatives for them to consider. Non-profit organizations like Engineers Without Borders holds sustainable international development as paramount to all international projects that their student and professional chapters undertake. The Cal Poly Engineers Without Borders student chapter has implemented a variety of projects from slow sand filters to compressed earth blocks, and the Nicaragua team is in the process of designing a health clinic for the Camilo Ortega community. In order to power the health clinic, …

Economic Optimization Of Offshore Wind Farms Using The Geometric Algorithm, Mahidhar Nandigam

Electrical & Computer Engineering Theses & Dissertations

The research project related to this thesis focuses on the optimization of electrical systems for offshore wind farms for a given capacity. The optimal design and planning is a critical issue for developing cost effectively Offshore Wind Farms in energy systems. The Geometric Optimization Algorithms approach has been adopted to develop an optimization program, where the main components of the electrical system of an offshore wind farm and key technical specifications are used as parameters to be optimized for a minimum cost with necessary constraints. The effectiveness of the optimization program can be evaluated with real-time comparison between offshore wind …

Economic Analysis Of A Brackish Water Photovoltaic-Operated (Bwro-Pv) Desalination System, Ali Al-Karaghouli, Lawrence L. Kazmerski

Publications (E)

The photovoltaic (PV)-powered reverse-osmosis (RO) desalination system is considered one of the most promising technologies in producing fresh water from both brackish and sea water, especially for small systems located in remote areas. We analyze the economic viability of a small PV-operated RO system with a capacity of 5 m³/day used to desalinate brackish water of 4000 ppm total dissolve solids, which is proposed to be installed in a remote area of the Babylon governorate in the middle of Iraq; this area possesses excellent insolation throughout the year. Our analysis predicts very good economic and environmental benefits of …

The Application Of Multi Frequency Resonant Controllers In In A Dfig To Improve Performance By Reducing Unwanted Power And Torque Pulsations And Reducing Current Harmonics., Joseph Kearney, Michael Conlon, Eugene Coyle

Conference papers

The paper describes a method to control the rotor-side and grid side converters in a DFIG when subjected to the effects of network voltage unbalance conditions. Multi Frequency Resonant Controllers are incorporated into the grid side and rotor side converters to assist in the control functions. The Resonant Controllers are tuned to twice the network frequency to assist in the control of power and torque pulsations and to three times the network frequency to assist in the control of the generated third harmonic currents. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque …

The Application Of Multi Frequency Resonant Controllers In In A Dfig To Improve Performance By Reducing Unwanted Power And Torque Pulsations And Reducing Current Harmonics., Joseph Kearney, Michael Conlon, Eugene Coyle

Conference papers

The paper describes a method to control the rotor-side and grid side converters in a DFIG when subjected to the effects of network voltage unbalance conditions. Multi Frequency Resonant Controllers are incorporated into the grid side and rotor side converters to assist in the control functions. The Resonant Controllers are tuned to twice the network frequency to assist in the control of power and torque pulsations and to three times the network frequency to assist in the control of the generated third harmonic currents. A DFIG model is implemented in Matlab/Simulink and simulations show the reduction in power and torque …

Wavelet Based Islanding Detection Of Dc-Ac Inverter Interfaced Dg Systems, Mohamed Moin Hanif, Malabika Basu, Kevin Gaughan

Conference papers

The increased penetration of distributed generation (DG) often connected to grid through dc-ac interface has made islanding detection an important and challenging issue to power engineers. Several methods based on passive and active detection scheme have been proposed in the literature. While passive schemes have a large non detection zone (NDZ), concern has been raised on active method due to its degrading power quality effect. This paper proposes a wavelet based passive islanding detection scheme with almost zero NDZ for dc-ac inverter interfaced grid connected DGs. The key idea is to utilize the spectral changes in the higher frequency components …

User's Guide To Mbc3: Multi-Blade Coordinate Transformation Code For 3-Bladed Wind Turbine, G. S. Bir

Publications (E)

The dynamics of wind turbine rotor blades are conventionally expressed in rotating frames attached to the individual blades. The tower-nacelle subsystem though, sees the combined effect of all rotor blades, not the individual blades. Also, the rotor responds as a whole to excitations such as aerodynamic gusts, control inputs, and tower-nacelle motion—all of which occur in a nonrotating frame. Multi-blade coordinate transformation (MBC) helps integrate the dynamics of individual blades and express them in a fixed (nonrotating) frame. MBC involves two steps: transforming the rotating degrees of freedom and transforming the equations of motion. Reference 1 details the MBC operation. …

Green Power Marketing In The United States: A Status Report (2009 Data), Lori Bird, Jenny Sumner

Publications (E)

This report documents green power marketing activities and trends in the United States. Aggregate green power sales data for all voluntary purchase markets across the United States are presented for 2009. The data presented in this report are based primarily on figures provided to NREL by utilities and independent renewable energy marketers. Because data cannot be obtained from all market participants, the estimates presented here likely represent an underestimate of the market size. Key trends identified in this year’s report include:
• In 2009, total retail sales of renewable energy in voluntary markets exceeded 30 million MWh, an increase of …

An In Situ Fourier Transform Infrared Spectroelectrochemical Study On Alcohols Electrocatalytic Oxidation At Pd Electrode In Acidic Solution, Hai-Ping Huang, Lian-Qin Wang, Pei-Kang Shen

Journal of Electrochemistry

The methanol and ethylene glycol electrooxidation on palladium electrode in acidic solution has been investigated by cyclic voltammetry and in situ Fourier transform infrared spectroelectrochemistry. It shows that the oxidation of methanol and ethylene glycol at Pd electrode cannot proceed until over 1.5 V in acidic and neutral media. The overpotential decreases and the peak current density increases with the reduction in pH values. The formation of the oxygen-containing species significantly affects the alcohol oxidation on Pd electrode. The in situ FTIR spectroscopic measurements show that the oxidation products of ethylene glycol on Pd electrode are CO₂ and oxalic …

Comparative Study Of Nanoporous Pt, Ptru And Ptruir Catalysts Using Electrochemical Ftir Spectroscopy, M. Amussen Robert, Holt-Hindle Peter, Nigro Samantha, Aicheng Chen

Journal of Electrochemistry

In recent years much effort has been put towards developing efficient Pt-based electrocatalysts for applications in fuel cells. With the rising cost of precious metals such as Pt,the need to enhance the activity and to decrease the load of catalysts is prominent. Herein we report on the synthesis and comparative study of nanoporous Pt,PtRu and PtRuIr electrocatalysts. The nanoporous electrodes were fabricated using a hydrothermal method and characterized by scanning electron microscopy (SEM) ,energy dispersive spectroscopy (EDS) ,X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) . The electrocatalytic activity of the fabricated nanopo- rous materials was evaluated using both CO …

Electrooxidation Of Carbon Monoxide On Pd Thin Film-Coated Au Electrodes: Film Thickness Dependence, Yuqing Yang, Shouzhong Zou

Journal of Electrochemistry

The adsorption and electrooxidation of CO on Pd-coated Au electrodes were studied by cyclic voltammetry and surface-enhanced Raman spectroscopy (SERS) . It is found that CO oxidation activity is film thickness dependent. Cyclic voltammograms (CVs) showed that CO oxidation peak potential shifted positively with the increase of the Pd thickness. SERS showed a redshift of the C—O stretching frequency with increasing Pd film thickness. These observations were explained by the dband theory. The strain effect strengthens CO adsorption and stabilizes adsorbed CO,while the ligand effect weakens CO adsorption and eases its oxidation. The ligand effect overpowers the strain effect.

In Situ Surface-Enhanced Raman Scattering Spectroscopic Study Of Sulfur Adsorption On Polycrystalline Platinum Electrode Surface, Bolian Xu, In-Su Park, Ying Li, De-Jun Chen, Yuye J. Tong

Journal of Electrochemistry

The paper reports the first in situ surface enhanced Raman scattering (SERS) spectroelectrochemistry study of sulfur adsorption and electro-oxidation on highly roughened polycrystalline Pt surface in both acidic and basic supporting electrolytes. The SERS spectra were taken at a constant electrode potential after accumulative electro-oxidation CVs of the Pt electrode with pre-adsorbed sulfur species and at different electrode potentials that were varied stepwise of the Pt electrode immersed in sulfur-containing electrolytes without pre-adsorbed sulfur species. In both cases,a dominant vibrational band at 299 cm^-1 in acidic electrolyte but at 310 cm^-1 in basic electrolyte was observed,which was assigned …

Studies Of Oxidation Processes Of Adsorbed And Solution Co On Pt(110) Electrode By Cyclic Voltammetry And In Situ Ftirs, Li Tian, Jun-Tao Li, Jin-Yu Ye, Chun-Hua Zhen, Shi-Gang Sun

Journal of Electrochemistry

The oxidation processes of adsorbed CO (COad) and solution phase CO (COsol) on Pt(110) electrode were investigated by cyclic voltammetry and in-situ FTIR spectroscopy. It has revealed that in comparison with COad on Pt(110) in a CO-free solution,the oxidation current peak of COsol in a CO-saturated solution is positively shifted ca. 168 mV,and the peak current density has been increased by 6. 70 times. Linear adsorbed CO (COL) is determined by in-situ FTIR spectroscopy as the main species,which is uniformly distributed on Pt (110) surface. In a CO-free solution,the onset potential of COL is measured by in-situ FTIRS ca. 0. …

Solid State Nmr Studies Of Lithium Manganese Silicate As Positive Electrode Materials For Li-Ion Batteries, Hu Cheng, Zi-Geng Liu, Yi-Xiao Li, Zhong Chen, Yong Yang

Journal of Electrochemistry

The Li₂MnSiO₄ cathode material for lithium ion batteries was synthesized by sol-gel assisted hydrothermal method. XRD,FTIR and SS-NMR were used to study the phase,structure and morphology of obtained samples. Electrochemical performance of cathode material was tested. The results show that the main phase of sample prepared was Li₂MnSiO₄,whereas a small amount of impurities (Li₂CO₃) were existed. The Li₂MnSiO₄ cathode material gave an initial discharging capacity of about 190 mAh·g ^-1. But this capacity faded rapidly during the cycling process due to the decomposition of Li …

Tracking Simultaneous Time-Varying Power Harmonic Distortions Using Filter Banks, Carlos A. Duque, Paulo M. Silveira, Thomas L. Baldwin, Paulo F. Ribeiro

University Faculty Publications and Creative Works

Although it is well known that the Fourier analysis is only accurately applicable to steady-state waveforms, it is a widely used tool to study and monitor time-varying signals, such as are commonplace in electrical power systems. The disadvantages of the Fourier analysis, such as frequency spillover or problems due to sampling (data window) truncation can often be minimized by various windowing techniques, but they nevertheless exist. This paper demonstrates that it is possible to track and visualize amplitude and time-varying power systems harmonics, without frequency spillover caused by classical time-frequency techniques. This new tool allows for a clear visualization of …