Power and Energy Commons^™

Modeling Of Chemical-Mechanical Couplings In Anode-Supported Solid Oxide Fuel Cells And Reliability Analysis, Xinfang Jin, Xingjian Xue

Faculty Publications

Oxygen ionic transport in conducting ceramics is an important mechanism enabling solid oxide fuel cell (SOFC) technology. The multi-physicochemical processes lead to the fact that the distribution of oxygen vacancy site fraction is not uniform in a positive-electrode electrolyte negative-electrode (PEN) assembly. Different oxygen vacancy concentrations induce different volumetric expansion of ceramics, resulting in complicated chemical–mechanical coupling phenomena and chemical stress in SOFCs. In this research, a mathematical model is developed to study oxygen ionic transport induced chemical stress in an SOFC. The model is validated using experimental polarization curves. Comprehensive simulations are performed to investigate chemical stress distribution in …

Testing Of Two Novel Semi-Implicit Particle-In-Cell Techniques, Trenton J. Godar

Browse all Theses and Dissertations

PIC (Particle-in-cell) modeling is a computational technique which functions by advancing computer particles through a spatial grid consisting of cells, on which can be placed electric and magnetic fields. This method has proven useful for simulating a wide range of plasmas and excels at yielding accurate and detailed results such as particle number densities, particle energies, particle currents, and electric potentials. However, the detailed results of a PIC simulation come at a substantial cost of computational requirement and the algorithm can be susceptible to numerical instabilities. As processors become faster and contain more cores, the computational expense of PIC simulations …

Cost And Benefit Analysis Of Shore Side Electricity In The Port Of Tanjung Perak, Indonesia, Oscar Yogi Yustiano

World Maritime University Dissertations

No abstract provided.

Fault Location Algorithms, Observability And Optimality For Power Distribution Systems, Wanjing Xiu

Theses and Dissertations--Electrical and Computer Engineering

Power outages usually lead to customer complaints and revenue losses. Consequently, fast and accurate fault location on electric lines is needed so that repair work can be carried out as fast as possible.

Chapter 2 describes novel fault location algorithms for radial and non-radial ungrounded power distribution systems. For both types of systems, fault location approaches using line to neutral or line to line measurements are presented. It’s assumed that network structure and parameters are known, so that during-fault bus impedance matrix of the system can be derived. Functions of bus impedance matrix and available measurements at substation are formulated, …

Modeling And Validation Of A Synchronous-Machine/Controlled-Rectifier System, Kyle A. Hord

Theses and Dissertations--Electrical and Computer Engineering

The hardware validation of a novel average-value model (AVM) for the simulation of a synchronous-generator/controlled rectifier system is presented herein. The generator is characterized using genetic algorithm techniques to fit standstill frequency response (SSFR) measurements to q and d-axis equivalent circuits representing the generator in the rotor reference frame. The generator parameters form the basis of a detailed model of the system, from which algebraic functions defining the parametric AVM are derived. The average-value model is compared to the physical system for a variety of loading and operating conditions including step load change, change in delay angle, and external closed-loop …

A New Design Of Dc-Dc Converter For Capacitive Deionization Process, Zhiao Li

Theses and Dissertations--Electrical and Computer Engineering

The shortage of clean water has become a significant global problem, and capacitive deionization (CDI) is a technology that can be used to help relieve the problem. A Ćuk converter system that can recover energy from CDI cells is described. This converter transfers energy between two CDI cells when a cell is in its desorption period, allowing energy that would otherwise be lost to be recovered and improving overall system efficiency. In order to control the states of the MOSFET switches in the converter, a self boost charge pump is used. In this way, the microcontroller can control system duty …

Coordinated Voltage And Reactive Power Control Of Power Distribution Systems With Distributed Generation, Esa A. Paaso

Theses and Dissertations--Electrical and Computer Engineering

Distribution system voltage and VAR control (VVC) is a technique that combines conservation voltage reduction and reactive power compensation to operate a distribution system at its optimal conditions. Coordinated VVC can provide major economic benefits for distribution utilities. Incorporating distributed generation (DG) to VVC can improve the system efficiency and reliability. The first part of this dissertation introduces a direct optimization formulation for VVC with DG. The control is formulated as a mixed integer non-linear programming (MINLP) problem. The formulation is based on a three-phase power flow with accurate component models. The VVC problem is solved with a state of …

A Sensitivity Analysis Toolkit For The Simplification Of Mv Distribution Network Voltage Management, Fabian Tamp, Philip Ciufo

Dr Philip Ciufo

As distribution networks become increasingly variable and generation becomes increasingly decentralised, voltage standards are becoming more liable to violation. Accordingly, intelligent voltage management strategies are required to enable standards compliance without unduly increasing network maintenance or infrastructure costs. The relationship between network power and voltages, however, is complex, non-linear and interdependent, and thus is difficult to conceptualise and use for decision-making and control purposes.

This paper introduces a software toolkit that simplifies the development of voltage management strategies by the applica- tion of sensitivity analysis. Sensitivity analysis reduces complex network P – Q – |V | relationships to simple linear …

Comparison Of An Analytical Hierarchy Process And Fuzzy Axiomatic Design For Selecting Appropriate Photovoltaic Modules For Onboard Vehicle Design, Mahmoud M. Abdelhamid

Mahmoud M Abdelhamid

In this paper, the authors present an overview of the available commercial photovoltaic (PV) module options for powering onboard vehicle applications. The authors used two decision-making methodologies to determine the evaluation factors and the decision-making criteria necessary for assessing the suitability of a particular PV module type. In both the analytical hierarchy process (AHP) and the fuzzy axiomatic design (AD), the authors used at the input stage quality function deployment (QFD) to determine customer requirements for a vehicle with PV module capabilities. This approach is innovative in that evaluation depended upon data collected from PV manufacturers’ datasheets. This approach is …

Cmk-3/Sulfur Composite (CXSY) And Room-Temperature Na/S Battery, Qing Zhao, Yu-Xiang Hu, Kai Zhang, Li-Jiang Wang, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

A series of ordered mesoporous carbon (CMK-3)/sulfur composite (C_xS_y) with different sulfur contents were synthesized via a melt-diffusion method. XRD, Raman, BET, SEM, and TEM techniques were used to characterize the structure and morphology of the as-prepared composite. The electrochemical performance of CMK-3/sulfur composite as the electrode of Na/S battery was tested at room temperature. Cyclic voltammograms show that one obvious reduction peak was located at about 1.61V, which is corresponding to the formation of Na₂S_x (x=2~5), while two oxidation peaks were displayed at about 1.82V and 1.95V, which are belonging to the …

Surface Composition Structure And Electrochemical Performance Of Aluminum Doped Lifepo4, Huai-Fang Shang, Wei-Feng Huang, Wang-Sheng Hu, Ding-Guo Xia, Zi-Yu Wu

Journal of Electrochemistry

Despite there are many successful reports about the preparation of electrode materials with surface coating for lithium ion batteries, the study in surface self-coating of cathode materials using segregation of doping elements and their electrochemical properties is still very rare. The LiFePO₄ particles with rich-Al on the surface were synthesized by one step solvothermal route. TEM results demonstrated that the surface of the obtained LiFePO₄ particles was well-covered by the amorphous coating. The soft X-ray absorption spectroscopy (XAS) and Auger electron spectroscopy (AES) component analyses revealed that the amorphous coating was composed of LiFe_1-xAl_xPO …

Controllable Synthesis Of Dispersed Spherical Fe3O4 Nanoparticles As Lithium-Inserted Materials, Hong-Li Zou, Wei-Shan Li

Journal of Electrochemistry

Dispersed spherical Fe₃O₄ nanoparticles were synthesized by a hydrothermal method. The influences of odecyl trimethyl ammonium bromide (DTAB) concentration on the morphology and particle size of the as-prepared Fe₃O₄ were studied. Electrochemical performance of the as-prepared sample as anode materials of lithium ion battery was investigated. It is found that the as-prepared sample exhibits superior rate performance and cycle performance. The nano-sized materials provide structural stability and favor the transfer of lithium ions.

Electrochemical Na-Storage Materials And Their Applications For Na-Ion Batteries, Jiang-Feng Qian, Xue-Ping Gao, Han-Xi Yang

Journal of Electrochemistry

Oncoming large scale electric energy storage (EES) requires battery systems not only to have sufficient storage capacity but also to be cost-effective and environmentally friendly. Li-ion batteries for widespread EES applications may be limited due to the constraint of global lithium resource. From the considerations of available resources and environmental impact, Na-ion batteries have potential advantages as next generation secondary batteries and an alternative to Li-ion batteries. However, in the present state of the art, the Na-storage cathodes reported so far are still deficient both in energy density and power capability, while the carbon and alloy anodes for Na-ion batteries …

Application Of Synchrotron Radiation Based Electrochemical In-Situ Techniques To Study Of Electrode Materials For Lithium-Ion Batteries, Zheng-Liang Gong, Wei Zhang, Dong-Ping Lv, Xiao-Gang Hao, Wen Wen, Zheng Jiang, Yong Yang

Journal of Electrochemistry

Due to its merits of high brightness and high intensity, high level of polarization and wide tunability in energy, etc., synchrotron radiation technique provides an unique platform for analysis of the relationship among composition–structure–performance of materials for lithium ion batteries, especially for in-situ, real time dynamic investigation of the electrochemical reaction mechanism, aging process and failure mechanism during charge-discharge cycling. In this paper, we review the latest developments in application of synchrotron based electrochemical in-situ experimental methods to studies of lithium ion batteries. The paper mainly focuses on the application of electrochemical in-siu XRD and XAFS techniques to the investigations …

Preparation And Electrochemical Properties Of Amorphous Znsno3/C By Hydrothermally Carbonization Method, Guo-Qing Fang, Rui-Xue Zhang, Wei-Wei Liu, Bing-Bo Xia, Hong-Dan Sun, Hai-Bo Wang, Jing-Jing Wu, Shinko Kaneko, De-Cheng Li

Journal of Electrochemistry

The amorphous ZnSnO₃@C composite was synthesized via a simple glucose hydrothermal and subsequent carbonization approach. The structure, morphology and electrochemical property of the composite were characterized by XRD, TEM and electrochemical measurements. Compared to bare ZnSnO₃, the ZnSnO₃/C composite exhibited markedly enhanced lithium storage property and cycle performance, delivering a reversible capacity of 659 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.

An Investigation On The Solid Electrolyte Interphase Of Silicon Anode For Li-Ion Batteries Through Force Curve Method, Jie-Yun Zheng, Hao Zheng, Rui Wang, Hong Li, Li-Quan Chen

Journal of Electrochemistry

Non-aqueous electrolyte has been widely used in commercial Li-ion batteries. Optimized choices are proceeding among the various types of salts and solvents in an effort to achieve higher performance of electrolyte. However, the electrolyte will be reduced in low potential and the reductive product will be deposited on the surface of anode to form a passivating layer, solid electrolyte interphase (SEI). Herein an atomic force microscopy (AFM) based method was introduced to study the structure and mechanical property of SEI on silicon thin film anode during the first cycle. Silicon has been known as the most potential candidate anode for …

Aqueous Solution-Evaporation Route Synthesis And Phase Structural Research Of The Li-Rich Cathode Li1.23Ni0.09Co0.12Mn0.56O2 By In-Situ Xrd, Chong-Heng Shen, Shou-Yu Shen, Zhou Lin, Xiao-Mei Zheng, Hang Su, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The Li-rich Li_1.23Ni_0.09Co_0.12Mn_0.56O₂ material was synthesized via aqueous solution-evaporation route. The structure and morphology of the material were characterized by means of XRD and SEM. The results indicated that the single particle of the product was polygonal with the size of 330 nm and the structure was layered solid solution with a certain amount of Li₂MnO₃. Electrochemical tests showed that the first discharge capacity of the Li-rich layered material was 250.8 mAh·g^-1 at 0.1C，the capacity retention was 86.5% after 40 cycles. Through in-situ XRD study a …

Synthesis And Electrochemical Property Of Li2Fesio4/C Cathode Material By Solid State Method, Jiao-Li Sun, Zhi-Jiao Chen, Yi-Xiao Li, Hu Cheng

Journal of Electrochemistry

Li2FeSiO4/C cathode material was synthesized using Li₂SiO₃ and FeC₂O₄ as raw materials by solid state method. The structure and morphology of the material were characterized by XRD and SEM. The electrochemical properties of the material were studied by constant-current cyclic testing. The results show that Li₂FeSiO₄/C has a good electrochemical performance. The first discharge capacity of Li₂FeSiO₄/C cathode material at 30oC reached 167 mAhg^-1 when cycled at 10 mAg^-1 between 1.5 and 4.8 V.

Preparation And Electrochemical Properties Of Flake-Like Liv3O8 By Soft Template Assisted Sol-Gel Method As Anode Material For Aqueous Li-Ion Battery, Shuai Tan, Dan Sun, Hai-Yan Wang, Tian-Li Hou, Zhong-Xing Xiao, You-Gen Tang

Journal of Electrochemistry

Anode material has become the key issue for restricting the development of aqueous lithium ion battery (ALIB). Flake-like LiV3O8 materials were synthesized by sol-gel method using sodium dodecyl benzene sulfonate (SDBS) as a template. The XRD and SEM results showed that as-prepared flake-like LiV₃O₈ was of high purity with monoclinic system and P21/m space group. LiMn₂O₄//Li₂SO₄//LiV₃O₈ ALIB was assembled and tested. As observed, the flake-like LiV3O8 here exhibited good high-rate performance and cycling stability. A high discharge capacity of 154 mAh.g^-1 (based on the mass …

Synthesis And Electrochemical Performance Of Nano Licopo4 By Polyol Method, Fei Wang, Yang Jun

Journal of Electrochemistry

High potential LiCoPO₄ cathode material was synthesized by polyol method. Carbon layer of ca. 3 nm thick was coated on the LiCoPO4 surfaces by chemical vapor deposition from methylbenzene. Crystalline structure, morphology and electrochemical performance of the sample were studied by XRD, SEM, TEM, CV and galvanostatic charge/discharge curve. The synthesized material via polyol method showed a pure phase of LiCoPO₄. The LiCoPO₄/C electrode delivered a high discharge capacity of 132 mAh·g^-1 and maintained 78% of the initial capacity after 50 cycles at 0.1C rate. The two-step extraction/insertion behavior of Li⁺ in LiCoPO4/C …