Lithium Ion Hybrid Capacitor With High Energy Density, Xian-Zhong Sun, Xiong Zhang, Kai Wang, Yan-Wei Ma

Journal of Electrochemistry

Lithium ion hybrid capacitors are electrochemical energy storage devices combining the advantages of both Li-ion battery and electrochemical capacitor. They can be extensively used in many fields. However, the commercialization of lithium ion hybrid capacitor has been encountered several problems, e.g., the device structure design, the screening of materials, the pre-lithiation process, and the interface between electrolyte and electrode, etc. This review summarizes the recent research advances in lithium ion hybrid capacitor with high energy density, including the selection of the active materials in cathode/anode and the separator, the pre-lithiation method using the three-electrode structure, the high- and low-temperature performances, …

Template Induced Fabrication Of Nitrogen Doped Carbon Sheets As Electrode Materials In Supercapacitors, Tao Huang, Guang-Zhi Tao, Chong-Qing Yang, Deng Lu, Lie Ma, Dong-Qing Wu

Journal of Electrochemistry

Due to the good electrical conductivity, high specific surface area, and excellent chemical/mechanical stability, carbon nanomaterials with two-dimensional morphology have gradually become the hot topic of the research on supercapacitors. Herein, we report for the first time the fabrication of nitrogen doped carbon sheets (NCSs). In our approach, the sheet-like magnisum aluminum (MgAl) layered double hydroxide was used as the hard template, which was mixed with o-phenylene diamine and iron chloride. The following thermal treatment could render the polymerization and carbonization of o-phenylene diamine. The NCSs with ordered hexagonal architectures were formed by final etching process of the thermally treated …

Preparation And Characterization Of Cellulose Acetate-Based Separator For Lithium-Ion Batteries, Hua-Feng Luo, Yuan-Dong Qiao

Journal of Electrochemistry

To improve the electrolyte wettability and thermal resistance of separators used for lithium-ion battery, a novel cellulose acetate (CA)-based separator is facilely prepared by non-solvent induced phase separation (NIPS) wet-process and investigated in lithium-ion batteries. Systematical investigations including morphological characterization, electrolyte wettability and thermal resistance testing were carried out. The results demonstrated that the CA-based separator exhibited well developed three-dimensional porous structures with porosity up to 65%, which is 1.5 times higher than that of PE separator. The CA separator also showed excellent electrolyte uptake (285%) and thermal stability at 150 ^oC for 30 min. Compared with the commercial …

The Interval Grey Numbers Ranking Based On Risk Preferences, Zhaobin Li, Zhuo Zhang, Jian Liu, Shuai Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new method for ranking interval grey numbers to address the challenge in multi-criteria decision-making problems with interval grey numbers has been proposed. This new method involves the risk preferences of decision makers. First, we propose a new method to rank the interval grey numbers by comparing the possibility degree or whitened value. Second, we classify the decision makers into three different types according to their risk preferences then we establish the corresponding risk preference assumptions to solve the problem that different interval grey numbers with the same possibility degree or whitened value. Finally, we use a …

Magnus--An Ultra-High Specific Torque Pm Axial Flux Type Motor With Flux Focusing And Modulation, Vandana Rallabandi, Narges Taran, Dan M. Ionel, Ion G. Boldea

Power and Energy Institute of Kentucky Faculty Publications

Axial flux permanent magnet (AFPM) synchronous motors are attractive for low speed direct drive systems because of their high specific torque. The present paper proposes a novel axial flux machine topology, called MAGNUS, obtained by combining a yokeless central stator type NS arrangement with two external high polarity spoke-rotors, resulting in very high flux concentration. The stator, which includes main and auxiliary teeth for air-gap profiling has a small number of concentrated coils. Two stator configurations are discussed, the first, a yokeless construction with coils wound around the teeth, and the second with coils placed around the stator core in …

Quantitative Analysis Of Regenerative Energy In Electric Rail Traction Systems, Mahmoud Saleh, Oindrilla Dutta, Yusef Esa, Ahmed Mohamed

Publications and Research

This paper aims at determining the influential factors affecting regenerative braking energy in DC rail transit systems. This has been achieved by quantitatively evaluating the dependence of regenerative energy on various parameters, such as vehicle dynamics, train scheduling, ground inclination and efficiency of the electrical devices. The recuperated power and energy have been presented by a mathematical model, comprising of a set of empirical forms, which allows for thorough analysis. A detailed simulation model of a typical DC-traction system has been developed to validate the developed empirical forms. The results verified the validity of the proposed mathematical model, and demonstrated …

Inductance Testing According To The New Ieee Std 1812-Application And Possible Extensions For Ipm Machines, Vandana Rallabandi, Narges Taran, Dan M. Ionel, Ping Zhou

Power and Energy Institute of Kentucky Faculty Publications

Equivalent circuit parameters are very important for permanent magnet synchronous machines since they serve as the basis for performance estimation and implementation of power electronic drives controls. Specified in the newly approved IEEE Std 1812, a short-circuit test can be employed, in combination with an open-circuit measurement, in order to determine the back emf and the synchronous inductance. In this paper, it is shown that for interior permanent magnet (IPM) machines this approach can be used only to determine the d-axis inductance and additional and separate measurements are required for the q-axis inductance. In this respect, one method widely used …

Optimizing Distributed Energy Resources On A Distribution Feeder, Bill Henry, Stephen Macdonald, Nicole Wehner, Gabe Mcbride, Tyler Groth

Engineering and Technology Management Student Projects

The purpose of this study is to optimize a set of distributed energy resources (DERs) on an electric utility distribution level feeder. A DER is a decentralized resource, usually located at end-use electric utility customer sites, that stores or generates electricity – such as batteries and rooftop photovoltaic solar, or in the case of demand response, in which the utility has the ability to manage electricity consumption to the benefit of distribution grid operation. The aggregation and optimization of a set of DERs of disparate operating characteristics, over a period of three years is performed and the methods employed explained. …

Optimal Microgrids Placement In Electric Distribution Systems Using Complex Network Framework, Mahmoud Saleh, Yusef Esa, Nwabueze Onuorah, Ahmed Mohamed

Publications and Research

This paper provides a new approach to find the optimal location for Microgrids (MGs) in electric distribution systems using complex network analysis. An optimal location in this paper refers to a location that would result in increased grid resilience, reduced power losses, less line loading, higher voltage stability and secured supply to critical loads during power outage. The criteria used to find the optimal placement of MGs were based on the centrality analysis adopted from complex network theory, the center of mass concept used in physics, and the controlled delivery grid (CDG) concept. An IEEE 30-bus system was used as …

Energy Management Algorithm For Resilient Controlled Delivery Grids, Mahmoud Saleh, Yusef Esa, Ahmed Mohamed, Haim Grebel, Roberto Rojas-Cessa

Publications and Research

Resilience of the power grid is most challenged at power blackouts since the issues that led to it may not be fully resolved by the time the power is back. In this paper, a Real-Time Energy Management Algorithm (RTEMA) has been developed to increase the resilience of power systems based on the controlled delivery grid (CDG) concept. In a CDG, loads communicate with a central controller, periodically sending requests for power. The central controller runs an algorithm, based on which it may decide whether to grant the requested energy fully or partially. Therefore, the CDG limits loads discretionary access to …

Quantifying Forecast Uncertainty In The Energy Domain, Mohammad Saber

Dissertations (1934 -)

This dissertation focuses on quantifying forecast uncertainties in the energy domain, especially for the electricity and natural gas industry. Accurate forecasts help the energy industry minimize their production costs. However, inaccurate weather forecasts, unusual human behavior, sudden changes in economic conditions, unpredictable availability of renewable sources (wind and solar), etc., represent uncertainties in the energy demand-supply chain. In the current smart grid era, total electricity demand from non-renewable sources influences by the uncertainty of the renewable sources. Thus, quantifying forecast uncertainty has become important to improve the quality of forecasts and decision making. In the natural gas industry, the task …

Study Of Modified Deposition Process For Cu(In,Ga)Se2 Solar Cell Back Contact, Tasnuva Ashrafee

Electrical & Computer Engineering Theses & Dissertations

As the worldwide demand for renewable energy is increasing, growth of the global share of alternative energy sources would improve overall energy security as well as bring environmental benefits. So far, solar cells - the devices that convert direct sunlight into electricity - are dominated by silicon devices. Another alternative is thin film solar cell, whose main inspiration is to reduce the electricity production cost. Cu(In, Ga)Se₂ (CIGS) solar cells are considered to have a great prospective because of reduced material and energy consumption during manufacturing. Many CIGS solar cell manufacturers are already exhibiting GW-scale production capacity. With the …

Design Of Dc-Link Vscf Ac Electrical Power System For The Embraer 190/195 Aircraft, Eduardo Francis Carvalho Freitas, Nihad E. Daidzic

Journal of Aviation Technology and Engineering

A proposed novel DC-Link VSCF AC-DC-AC electrical power system converter for Embraer 190/195 transport category airplane is presented. The proposed converter could replace the existing conventional system based on the CSCF IDGs. Several contemporary production airplanes already have VSCF as a major or backup source of electrical power. Problems existed with the older VSCF systems in the past; however, the switched power electronics and digital controllers have matured and can be now, in our opinion, safely integrated and replace existing constant-speed hydraulic transmissions powering CSCF AC generators. IGBT power transistors for medium-level power conversion and relatively fast efficient switching are …

2017 Fall Engr333 Project Assignment, Matthew K. Heun

ENGR 333

The Fall 2017 ENGR333 project focused on campus energy cost savings.

I asked the students two questions:

• Section A: What would it take for Calvin to save $75k/year on natural gas costs?
• Section B: What would it take for Calvin to save $150k/year on energy costs (mostly electricity) using a new on-site co-gen plant?

Customer

The customer for this project was Phil Beezhold, Director of Calvin’s Physical Plant.

The Social Acceptance Of Community Solar: A Portland Case Study, Anne Weaver

Dissertations and Theses

Community solar is a renewable energy practice that's been adopted by multiple U.S. states and is being considered by many more, including the state of Oregon. A recent senate bill in Oregon, called the "Clean Electricity and Coal Transition Plan", includes a provision that directs the Oregon Public Utility Commission to establish a community solar program for investor-owned utilities by late 2017. Thus, energy consumers in Portland will be offered participation in community solar projects in the near future. Community solar is a mechanism that allows ratepayers to experience both the costs and benefits of solar energy while also helping …

Solar Powered Single-Axis Heliostat Active Solar Tracking Device, Mason Kyle Roberts

Physics

As a means of cooking food, the burning of biomass accounts for over 4 million premature deaths in third world countries (“Household Air Pollution and Health”). The focus of this project was to explore an alternative that could utilize focused sunlight to cook food. A solar tracker was designed to be affixed to a parabolic, reflective, tilted single axis heliostat to follow the sun throughout the day and focus the reflected light to the bottom of a cooking surface. This surface became hot enough to for the preparation of food or boiling/sterilization of water.

A goal for each project was …

Nigeria's Power Sector Roadmap: Policy Perspectives And Prospects, Bandele A. G. Amoo, O. M. Adebayo, Derek Ibeagha

Bullion

Various strategies have been employed over the years by the Government to boost power in the country. These strategies have been hinged on policies, reforms and roadmaps, including the 2005 Electric Power Sector Reform Act, the Roadmap for Power Sector Reform 2010 and the current Roadmap for Change. A perfunctory look at previous reforms has resulted in significant progress, including unbundling and privatizing the long-standing government-owned monopoly in the power sector. This paper takes a comprehensive assessment of the Roadmap of Change comparing it to previous policies, isolating policy perspectives, prospects and challenges facing it. It also gleans lessons from …

Density Functional Investigation On Cathode/Electrolyte Interface In Solid-State Lithium Batteries, Xuelong Wang, Ruijuan Xiao, Yong Xiang, Hong Li, Liquan Chen

Journal of Electrochemistry

The rapidly expanding application of lithium ion batteries stimulates research interest on energy storage devices with higher energy density, better safety and faster charge/discharge speed. All-solid-state lithium batteries have been considered as promising candidates because of their fewer side reactions and better safety compared with conventional lithium-ion batteries with organic liquid electrolytes. Looking for well-matched electrode/electrolyte interfaces is one of the keys to ensuring good comprehensive performance of solid-state lithium batteries. In this report, with the aid of first-principles simulations, the local structure and lithium ions transportation properties of electrolyte surfaces and cathode/electrolyte interfaces are investigated. The β-Li₃PS …

Effects Of Surface Modification Modes On Proton-Over-Vanadium Ion Selectivity Of Nafion®Membrane For Application In Vanadium Redox Flow Battery, Qing-Long Tan, Hai-Ning Wang, Shan-Fu Lu, Da-Wei Liang, Chun-Xiao Wu, Yan Xiang

Journal of Electrochemistry

The effect of surface modification modes on proton-over-vanadium ion selectivity was studied by spin-coating chitosan-Phosphotungstic Acid (PWA) as a single or double layer on Nafion membrane surface. To suppress the vanadium ions permeation through the Nafion? membrane in a vanadium redox flow battery (VRFB), the single surface-modified Nafion membrane (Nafion/chitosan-PWA)S and double surface-modified Nafion membrane (Nafion/chitosan-PWA)D demonstrated a 89.9% and 92.7% reduction of vanadium ion permeability in comparison with pristine Nafion, respectively. The (Nafion/chitosan-PWA)D exhibited betterhigher selectivity between proton and vanadium ions than the (Nafion/chitosan-PWA)S at the same layer thickness. Furthermore, the columbic efficiency for the VRFB single cell based …

Tetrabutylammonium Hexafluorophosphate As Flame Retardant Additive For Lithium Ion Batteries, Qing Zhao, Qian Zhang, Jing-Min Fan, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Safety issues have been attracted more and more attentions due to the wide applications of lithium ion batteries. Introducing flame retardant additives are one of the effective strategies to improve the safety of lithium-ion batteries. In this paper, the tetrabutylammonium hexafluorophosphate (TBAPF₆) as a flame retardant additive was added to the electrolyte as a flame retardant additive to enhance the safety of lithium ion batteries. The self-extinguishing time (SET) and ionic conductivities of the electrolytes with different TBAPF₆ contents were investigated. It is found that TBAPF6 dramatically reduced the flammability of the electrolyte while slightly decreasing ionic …

Electrochemical Performance Of Sodium Difluoro(Oxalato)Borate As The Additive Of Non-Aqueous Electrolytes For Sodium-Ion Batteries, Ding Zhang, Qin Zhu, Ying Wang, Cheng-Long Zhao, Shi-Bin Liu, Shou-Dong Xu

Journal of Electrochemistry

Sodium ion battery has attracted worldwide and intensive attention recently, while the adoption of electrolyte additives has been considered as one effective strategy to promote the cell performance. Within this work sodium difluoro(oxalato)borate (NaDFOB) was prepared and adopted as an additive for the general non-aqueous electrolyte formula of 1 mol·L-1 NaClO4/EC/PC (Vol: Vol=1:1), and the effects of the additive concentration on ionic conductivity and oxidization decomposition voltage were investigated in detail. In addition, the cell performance evaluated by NaNi0.5Mn0.5O2 as the cathode was also studied. It reveals that the addition of NaDFOB into the NaClO4/EC/PC electrolyte resulted in the significantly …

Thermo-Stability And Active Site Structure Of Fe/N/C Electrocatalyst For Oxygen Reduction Reaction, Chi Chen, Yu-Jiao Lai, Zhi-You Zhou, Xin-Sheng Zhang, Shi-Gang Sun

Journal of Electrochemistry

The development of Fe/N/C electrocatalyst for oxygen reduction reaction (ORR) is vital for the large-scale applications of proton exchange membrane fuel cells. Understanding the active site structure will contribute to the rational design of highly active catalysts. In this study, the as-prepared Fe/N/C catalyst based on poly-m-phenylenediamine (PmPDA-FeN_x/C) catalyst with the high ORR activity was subjected to the high-temperature heat treatment again at 1000 ~1500 ^oC. The degradation of in the ORR activity of PmPDA-FeN_x/C by with various heat treatments was correlated to the change of elemental compositions, chemical states and textural properties. As the …

A New Type Carbon Composited Molybdenum Doped Vanadium Oxide Nanowires As A Cathode Material For Sodium Ion Batteries, Guang-Rui Zhang, Li-Qiang Hu, Bao-Zhu Zhang

Journal of Electrochemistry

In recent years, the development of lithium ion batteries (LIBs) has been limited due to the insufficient lithium resource and increasing cost. As a promising candidate, sodium ion batteries (SIBs) with the similar electrochemical mechanism and lower cost than LIBs are developing rapidly. However, as a result of the larger radius of Na⁺ compared with Li⁺, the crystalline structures of the most electrode materials are damaged severely during the intercalation of Na⁺, which limits the electrochemical properties of SIBs. Thus, developing new types of electrode materials for SIBs is particularly important. Among the cathode materials, …

Radcool: A Web-Enabled Simulation Tool For Radiative Cooling, Yu-Wen Lin, Evan L. Schlenker, Zhiguang Zhou, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermophotovoltaic (TPV) systems can generate electricity from high-temperature heat sources via thermal radiation. However, the intense heating of a photovoltaic (PV) cell can greatly reduce the overall efficiency of the system. Therefore, it is critical to develop techniques to keep the PV cells close to ambient temperature without consuming energy. Radiative cooling is a passive technique that dissipates heat into remote space via thermal radiation. A simulation tool to predict the performance of radiative cooling systems would be particularly helpful in designing new experiments. The current TPV model simulation tool, TPVexpt, can calculate the theoretical performance of the TPV system. …

Carbon Removal And Optoelectronic Property Tuning In Copper Arsenic Sulfide Thin Films Through Ligand Exchange And Alloying, Louis R. Schroeder, Scott Mcclary, Rakesh Agrawal

The Summer Undergraduate Research Fellowship (SURF) Symposium

Solution processed thin film solar cells are attractive alternatives to conventional energy sources due to low waste generation, flexibility in substrate choice, and scalability. The novel semiconductor Cu3AsS4 in the enargite phase has a near ideal band gap of 1.4 eV and has earth abundant constituent elements; yet single-junction solar cells have yielded low efficiencies due to a secondary carbonaceous phase present, among other issues. This carbonaceous phase may be eliminated by exchanging the carbonaceous ligands with molecular metal chalcogenides. To characterize the ligand exchanged particles, UV-Vis-NIR spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and …

Thermal Characterization Of Magnetic Components, Jiazhou Zhong, Veda Samhitha Duppalli, Scott D. Sudhoff Professor

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermal limits are crucial constraints in the design of power magnetic components. As the power density of magnetic components continues to increase, cooling becomes more critical. Our research focuses on solving for the amount of cooling needed for a particular magnetic component. During the research process, a low-velocity wind tunnel designed and built from the ground up is used to form uniform and controlled conditions for the test components. Thermal Equivalent Circuit (TEC) and parameter identification techniques are used in conjunction to yield temperature distribution results. The expected result is temperature data on various areas of the component under different …

A Low Temperature Co-Fired Ceramic (Ltcc) Interposer Based Three-Dimensional Stacked Wire Bondless Power Module, Atanu Dutta

Graduate Theses and Dissertations

The objective of this dissertation research is to develop a low temperature co-fired ceramic (LTCC) interposer-based module-level 3-D wire bondless stacked power module. As part of the dissertation work, the 3-D wire bondless stack is designed, simulated, fabricated and characterized. The 3-D wire bondless stack is realized with two stand-alone power modules in a half-bridge configuration. Each stand-alone power module consists of two 1200 V 25 A silicon insulated-gate bipolar transistor (IGBT) devices in parallel and two 1200 V 20 A Schottky barrier diodes (SBD) in an antiparallel configuration. A novel interconnection scheme with conductive clamps and a spring loaded …

Realization Of A High Power Microgrid Based On Voltage Source Converters, Yusi Liu

Graduate Theses and Dissertations

Microgrid concepts are gradually becoming more popular because they are expected to interface with renewable energies, increase end users’ reliability and resiliency, and promote seamless integration of distributed generators (DG) and energy storage units [1]. Most units are connected through power electronics interfaces, such as ac-dc, dc-dc, and dc-ac converters. The converter design and control are critical to the stability and efficiency of a microgrid.

A microgrid may operate in either gird connected mode or islanded mode [1]. In terms of stability, the grid connected mode is less challenging compared to the islanded mode of operation due to the nearly …

The Impact Of Power Curve Estimation On Commercial Wind Power Forecasts - An Empirical Analysis, Gianni Goretti, Aidan Duffy, Tek Tjing Lie

Conference papers

An increasing number of utilities participating in the energy market require short term (i.e. up to 48 hours) power forecasts for renewable generation in order to optimize technical and financial performances. As a result, a large number of forecast providers now operate in the marketplace, each using different methods and offering a wide range of services. This paper assesses five different day-ahead wind power forecasts generated by various service providers currently operating in the market, and compares their performance against the state-of-the-art of short-term wind power forecasting. The work focuses on how power curve estimations can introduce systematic errors that …

Design & Evaluation Of A Hybrid Switched Capacitor Circuit With Wide-Bandgap Devices For Dc Grid Applications, Joshua L. Stewart

Electrical and Computer Engineering ETDs

ABSTRACT

As technologies advance, the rate at which renewable power sources, such as solar photovoltaic (PV) and wind, are being added to the power grid is increasing. Typically, PV power plants require large inverters for direct current to alternating current (DC-AC) power conversion, as well as large transformers to step up voltages to the grid voltage. Offshore wind farms and large PV power plants in remote locations often aggregate power on a DC bus in order to improve efficiency and reduce the cost of power conversion hardware within the energy complex. However, the power must still be converted to AC …