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2010

Missouri University of Science and Technology

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Full-Text Articles in Engineering

A Memory Saving Vector Fast Multipole Algorithm For Solving The Augmented Efie, Yang G. Liu, Weng Cho Chew, Li (Lijun) Jun Jiang Dec 2010

A Memory Saving Vector Fast Multipole Algorithm For Solving The Augmented Efie, Yang G. Liu, Weng Cho Chew, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

An augmented EFIE (A-EFIE)[9], [10] has been proposed to separate the contributions of the vector potential and the scalar potential for avoiding the imbalance at low frequencies. The corresponding low frequency fast multipole algorithm (LFFMA) [11] was also developed for solving the A-EFIE. Instead of the factorization of the scalar Green's function by using scalar addition theorem in the LF-FMA, we adopt the vector addition theorem for the factorization of the dyadic Green's function to realize memory savings. We are to develop a vector fast multipole algorithm for solving the A-EFIE. © 2010 IEEE.


A High-Quality Mach-Zehnder Interferometer Fiber Sensor By Femtosecond Laser One-Step Processing, Longjiang Zhao, Lan Jiang, Sumei Wang, Hai Xiao, Yongfeng Lu, Hai-Lung Tsai Dec 2010

A High-Quality Mach-Zehnder Interferometer Fiber Sensor By Femtosecond Laser One-Step Processing, Longjiang Zhao, Lan Jiang, Sumei Wang, Hai Xiao, Yongfeng Lu, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

During new fiber sensor development experiments, an easy-to-fabricate simple sensing structure with a trench and partially ablated fiber core is fabricated by using an 800 nm 35 fs 1 kHz laser. It is demonstrated that the structure forms a Mach-Zehnder interferometer (MZI) with the interference between the laser light passing through the air in the trench cavity and that in the remained fiber core. The fringe visibilities are all more than 25 dB. The transmission spectra vary with the femtosecond (fs) laser ablation scanning cycle. The free spectral range (FSR) decreases as the trench length increases. The MZI structure is …


A Comparative Verification Of Forecasts From Two Operational Solar Wind Models, Donald C. Norquist, Warner C. Meeks Dec 2010

A Comparative Verification Of Forecasts From Two Operational Solar Wind Models, Donald C. Norquist, Warner C. Meeks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The solar wind (SW) and interplanetary magnetic field (IMF) have a significant influence on the near‐Earth space environment. In this study we evaluate and compare forecasts from two models that predict SW and IMF conditions: the Hakamada‐Akasofu‐Fry (HAF) version 2, operational at the Air Force Weather Agency, and Wang‐Sheeley‐Arge (WSA) version 1.6, executed routinely at the Space Weather Prediction Center. SW speed (Vsw) and IMF polarity (Bpol) forecasts at L1 were compared with Wind and Advanced Composition Explorer satellite observations. Verification statistics were computed by study year and forecast day. Results revealed that both models’ mean Vsw are …


Process To Produce High Surface Area Nanoparticle Vanadium Phosphorus Oxide Catalyst And Product Derives Thereof, Yun Hin Taufiq-Yap, Ali A. Rownaghi Dec 2010

Process To Produce High Surface Area Nanoparticle Vanadium Phosphorus Oxide Catalyst And Product Derives Thereof, Yun Hin Taufiq-Yap, Ali A. Rownaghi

Chemical and Biochemical Engineering Faculty Research & Creative Works

An improved process to produce high surface area nanoparticle vanadium phosphorus oxide catalysts comprises the steps of reducing vanadium-containing compounds in an alcohol solution selected from the group consisting of isobutanol and benzyl alcohol and any combination derives thereof under reflux for 4 to 6 hours to form a suspended mixture; reacting dopants and phosphorus-containing compounds to the suspended mixture under reflux for 30 minutes to 3 hours to form precursors of the vanadium phosphorus oxide catalysts; drying the formed precursors; and calcining the dried precursors in a flow of gaseous n-butane/air mixture at 400 to 460° C. to form …


Note: Autonomous Pulsed Power Generator Based On Transverse Shock Wave Depolarization Of Ferroelectric Ceramics, S. I. Shkuratov, Jason Baird, E. F. Talantsev Dec 2010

Note: Autonomous Pulsed Power Generator Based On Transverse Shock Wave Depolarization Of Ferroelectric Ceramics, S. I. Shkuratov, Jason Baird, E. F. Talantsev

Mining Engineering Faculty Research & Creative Works

Autonomous pulsed generators utilizing transverse shock wave depolarization (shock front propagates across the polarization vector P0) of Pb(Zr0.52Ti0.48)O3 poled piezoelectric ceramics were designed, constructed, and experimentally tested. It was demonstrated that generators having total volume of 50 cm3 were capable of producing the output voltage pulses with amplitude up to 43 kV with pulse duration 4 µs. A comparison of high-voltage operation of transverse and longitudinal shock wave ferroelectric generators is given.


Product Technical Information, Steel Stud Manufacturers Association Dec 2010

Product Technical Information, Steel Stud Manufacturers Association

CCFSS Library (1939 - present)

No abstract provided.


Augmented Epa With Augmented Efie Method For Packaging Analysis, Zuhui Ma, Lijun Jiang, Wengcho Chew, Maokun Li, Zhiguo Qian Dec 2010

Augmented Epa With Augmented Efie Method For Packaging Analysis, Zuhui Ma, Lijun Jiang, Wengcho Chew, Maokun Li, Zhiguo Qian

Electrical and Computer Engineering Faculty Research & Creative Works

It is evident that the low frequency full wave electromagnetic modelling is necessary for IC packaging analysis. Considering the complexity, it is very difficult to solve the whole problem directly. Even though the domain decomposition method is a legitimate approach for these types of problems, the domain decomposition method based on the equivalence principle has the low frequency breakdown issue. In this paper, we developed a low frequency augmented equivalence principle algorithm (AEPA) with the augmented electric field integral equation (AEFIE) for packaging and IC analysis. On the equivalence surfaces, not only the electric current and the magnetic current, but …


Review Of Multi-Scale Electromagnetic Modeling, W. C. Chew, Lijun Jiang, H. Y. Chao, A. J. Hesford, M. K. Li, Z. G. Qian, Y. G. Liu, Y. P. Chen, Z. H. Ma, L. E. Sun, M. S. Tong, C. Davis, W. E.I. Sha Dec 2010

Review Of Multi-Scale Electromagnetic Modeling, W. C. Chew, Lijun Jiang, H. Y. Chao, A. J. Hesford, M. K. Li, Z. G. Qian, Y. G. Liu, Y. P. Chen, Z. H. Ma, L. E. Sun, M. S. Tong, C. Davis, W. E.I. Sha

Electrical and Computer Engineering Faculty Research & Creative Works

This paper reviews various methods to solve multiscale problems ranging from low-frequency methods to very high-frequency methods. ©2010 IEEE.


Robust Neural Network Rise Observer Based Fault Diagnostics And Prediction, James W. Fonda, S. (Sarangapani) Jagannathan, Steve Eugene Watkins Dec 2010

Robust Neural Network Rise Observer Based Fault Diagnostics And Prediction, James W. Fonda, S. (Sarangapani) Jagannathan, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

A novel fault diagnostics and prediction scheme in continuous time is introduced for a class of nonlinear systems. The proposed method uses a novel neural network (NN) based robust integral sign of the error (RISE) observer, or estimator, allowing for semi-global asymptotic stability in the presence of NN approximation errors, disturbances and unmodeled dynamics. This is in comparison to typical results presented in the literature that show only boundedness in the presence of uncertainties. The output of the observer/estimator is compared with that of the nonlinear system and a residual is used for declaring the presence of a fault when …


Decentralized State Feedback And Near Optimal Adaptive Neural Network Control Of Interconnected Nonlinear Discrete-Time Systems, Shahab Mehraeen, Jagannathan Sarangapani, Mariesa Crow Dec 2010

Decentralized State Feedback And Near Optimal Adaptive Neural Network Control Of Interconnected Nonlinear Discrete-Time Systems, Shahab Mehraeen, Jagannathan Sarangapani, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, first a novel decentralized state feedback stabilization controller is introduced for a class of nonlinear interconnected discrete-time systems in affine form with unknown subsystem dynamics, control gain matrix, and interconnection dynamics by employing neural networks (NNs). Subsequently, the optimal control problem of decentralized nonlinear discrete-time system is considered with unknown internal subsystem and interconnection dynamics while assuming that the control gain matrix is known. For the near optimal controller development, the direct neural dynamic programming technique is utilized to solve the Hamilton-Jacobi-Bellman (HJB) equation forward-in-time. The decentralized optimal controller design for each subsystem utilizes the critic-actor structure …


Cold-Formed Steel Framing Seismic Design Optimization Phase 1a: Seismic Equivalency Parameter Evaluation, American Iron And Steel Institute Nov 2010

Cold-Formed Steel Framing Seismic Design Optimization Phase 1a: Seismic Equivalency Parameter Evaluation, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.


Regeneration Of Exhausted Carbon Nano-Foam Used In Desalination Of Brackish Water, Sanjay Tewari, Bill Batchelor Nov 2010

Regeneration Of Exhausted Carbon Nano-Foam Used In Desalination Of Brackish Water, Sanjay Tewari, Bill Batchelor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Carbon Nano-Foam (CNF) has been used electrochemically for water desalination. CNF electrodes attract oppositely charged ions flowing in between them and this process is known as Capacitive De-Ionization (CDI). Once saturated these electrodes lose electrochemical adsorption and need to be replaced, this increases the cost of the treatment process as CNF is expensive. The goal of this study is to obtain optimal regeneration and predictive capability by examining CNF electrodes during regeneration and developing a model to describe desorption behavior. Various experiments were conducted to explore the effect of shorting, changing polarity of electrodes, flow velocity of water over CNF …


Dynamic Response Improvement In A Buck Type Converter Using Capacitor Current Feed-Forward Control, Lisheng Shi, Mehdi Ferdowsi, Mariesa Crow Nov 2010

Dynamic Response Improvement In A Buck Type Converter Using Capacitor Current Feed-Forward Control, Lisheng Shi, Mehdi Ferdowsi, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The dynamic performance of dc-dc power electronic converters is mainly determined by the output filtering capacitor and inductor, control loop(s) compensator(s), and the voltage conversion ratio. Normally, a larger capacitance and/or a smaller inductance are not recommended because of the extra cost and size of the capacitor and/or the increment of the inductor current ripple. The capacitor current feed-forward method has gained popularity due its fast dynamic response, simpler structure, and less sensing losses. In applications where a large voltage conversion ratio is needed, dynamic response for a load step-down scenario is worse than that of a load step-up condition. …


A Novel Real-Time Approach To Unified Power Flow Controller Validation, Keyou Wang, Mariesa Crow, Bruce M. Mcmillin, Stan Atcitty Nov 2010

A Novel Real-Time Approach To Unified Power Flow Controller Validation, Keyou Wang, Mariesa Crow, Bruce M. Mcmillin, Stan Atcitty

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the development of a real-time hardware/software laboratory to interface a soft real-time power system simulator with multiple unified power flow controllers (UPFC) via hardware-in-the-loop (HIL) to study their dynamic responses and validate control and placement approaches. This paper describes a unique laboratory facility that enables large-scale, soft real-time power system simulation coupled with the true physical behavior of a UPFC as opposed to the controller response captured by many other real-time simulators. The HIL line includes a synchronous machine, a UPFC, and a programmable load to reproduce the physical dynamics of the UPFC sub-network.


A Thermal Simulation Process Based On Electrical Modeling For Complex Interconnect, Packaging, And 3di Structures, Lijun Jiang, Chuan Xu, Barry J. Rubin, Alan J. Weger, Alina Deutsch, Howard Smith, Alain Caron, Kaustav Banerjee Nov 2010

A Thermal Simulation Process Based On Electrical Modeling For Complex Interconnect, Packaging, And 3di Structures, Lijun Jiang, Chuan Xu, Barry J. Rubin, Alan J. Weger, Alina Deutsch, Howard Smith, Alain Caron, Kaustav Banerjee

Electrical and Computer Engineering Faculty Research & Creative Works

To reduce the product development time and achieve first-pass silicon success, fast and accurate estimation of very-large-scale integration (VLSI) interconnect, packaging and 3DI (3D integrated circuits) thermal profiles has become important. Present commercial thermal analysis tools are incapable of handling very complex structures and have integration difficulties with existing design flows. Many analytical thermal models, which could provide fast estimates, are either too specific or oversimplified. This paper highlights a methodology, which exploits electrical resistance solvers for thermal simulation, to allow acquisition of thermal profiles of complex structures with good accuracy and reasonable computation cost. Moreover, a novel accurate closed-form …


Thermodynamics Of Strained Vanadium Dioxide Single Crystals, Yijia Gu, Jinbo Cao, Junqiao Wu, Long-Qing Chen Oct 2010

Thermodynamics Of Strained Vanadium Dioxide Single Crystals, Yijia Gu, Jinbo Cao, Junqiao Wu, Long-Qing Chen

Materials Science and Engineering Faculty Research & Creative Works

Vanadium dioxide undergoes a metal-insulator transition, in which the strain condition plays an important role. To investigate the strain contribution, a phenomenological thermodynamic potential for the vanadium dioxide single crystal was constructed. The transformations under the uniaxial stress, wire, and thin film boundary conditions were analyzed, and the corresponding phase diagrams were constructed. The calculated phase diagrams agree well with existing experimental data, and show that the transformation temperature (and Curie temperature) strongly depends on the strain condition.


Distributed Power Balancing For The Freedm System, Rav Akella, Fanjun Meng, Derek Ditch, Bruce M. Mcmillin, Mariesa Crow Oct 2010

Distributed Power Balancing For The Freedm System, Rav Akella, Fanjun Meng, Derek Ditch, Bruce M. Mcmillin, Mariesa Crow

Computer Science Faculty Research & Creative Works

The FREEDM microgrid is a test bed for a smart grid integrated with Distributed Grid Intelligence (DGI) to efficiently manage the distribution and storage of renewable energy. Within the FREEDM system, DGI applies distributed algorithms in a unique way to achieve economically feasible utilization and storage of alternative energy sources in a distributed fashion. The FREEDM microgrid consists of residential or industrial nodes with each node running a portion of the DGI process called Intelligent Energy Management (IEM). Such IEM nodes within FREEDM coordinate among themselves to efficiently and economically manage their power generation, utility and storage. Among a variety …


Comparison Of Antibacterial Properties Of Commercial Bone Cements And Fillers With A Zinc-Based Glass Polyalkenoate Cement, A. W. Wren, N. M. Cummins, Mark R. Towler Oct 2010

Comparison Of Antibacterial Properties Of Commercial Bone Cements And Fillers With A Zinc-Based Glass Polyalkenoate Cement, A. W. Wren, N. M. Cummins, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Postoperative infection following invasive surgical procedures is a significant cause for concern, particularly in spinal reconstructive surgery. The objective of this study is to compare the antibacterial efficacy of a novel zinc-based glass polyalkenoate cement (Zn-GPC) based on 0.04SrO-0.12CaO-0.36ZnO- 0.48SiO2 glass, to a number of commercially available bone cements and fillers including Simplex P + Tobramycin (STob), Spineplex (Spine) and Novabone Putty (NPut). The agar diffusion test was performed on each material against Escherichia coli, Staphlococcus epidermidis, Pseudomonas aeruginosa and Staphlococcus Aureus. STob was found to produce large inhibition zones in each …


Intelligent Coordinated Control Of A Wind Farm And Distributed Smartparks, Pinaki Mitra, Ganesh K. Venayagamoorthy Oct 2010

Intelligent Coordinated Control Of A Wind Farm And Distributed Smartparks, Pinaki Mitra, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Energy storage is generally recommended in presence of an intermittent source like wind farm for a better control over the power generation from the wind turbine with the variation of the wind speed. In this paper, the potential of plug-in electric vehicle parking lot (SmartPark) as an energy storage in a power system with a large wind farm has been investigated. Also, a fuzzy logic based coordination controller of the wind farm and the distributed SmartParks has been proposed in this paper. The fuzzy controller uses the total state-of-charge of the SmartParks and the difference between instantaneous demand and the …


Pso Tuned Flatness Based Control Of A Magnetic Levitation System, Ganesh K. Venayagamoorthy, E. C. Anene Oct 2010

Pso Tuned Flatness Based Control Of A Magnetic Levitation System, Ganesh K. Venayagamoorthy, E. C. Anene

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation on the application of flatness-based feedback linearization to the magnetic levitation model of INTECOTm Maglev system is presented in this paper. The MAGLEV system dynamics studied consists of a set of third order nonlinear differential equations. Using computational techniques proposed by Levine, it is verified that the ball position is the flat output. The derived flat output is applied in the construction of a nonlinear control law used to control the levitation to a set point as well as tracking a sine function trajectory. The controller gains are obtained and optimized using particle swarm optimization. The simulation results compared …


An Automated Phenotype-Driven Approach (Geneforce) For Refining Metabolic And Regulatory Models, Dipak Barua, Joonhoon Kim, Jennifer L. Reed Oct 2010

An Automated Phenotype-Driven Approach (Geneforce) For Refining Metabolic And Regulatory Models, Dipak Barua, Joonhoon Kim, Jennifer L. Reed

Chemical and Biochemical Engineering Faculty Research & Creative Works

Integrated constraint-based metabolic and regulatory models can accurately predict cellular growth phenotypes arising from genetic and environmental perturbations. Challenges in constructing such models involve the limited availability of information about transcription factor-gene target interactions and computational methods to quickly refine models based on additional datasets. In this study, we developed an algorithm, GeneForce, to identify incorrect regulatory rules and gene-protein-reaction associations in integrated metabolic and regulatory models. We applied the algorithm to refine integrated models of Escherichia coli and Salmonella typhimurium, and experimentally validated some of the algorithm's suggested refinements. The adjusted E. coli model showed improved accuracy …


The Effect Of Ionic Dissolution Products Of Ca-Sr-Na-Zn-Si Bioactive Glass On In Vitro Cytocompatibility, S. Murphy, A. W. Wren, Mark R. Towler, D. Boyd Oct 2010

The Effect Of Ionic Dissolution Products Of Ca-Sr-Na-Zn-Si Bioactive Glass On In Vitro Cytocompatibility, S. Murphy, A. W. Wren, Mark R. Towler, D. Boyd

Chemical and Biochemical Engineering Faculty Research & Creative Works

Many commercial bone grafts cannot regenerate healthy bone in place of diseased bone. Bioactive glasses have received much attention in this regard due to the ability of their ionic dissolution products to promote cell proliferation, cell differentiation and activate gene expression. Through the incorporation of certain ions, bioactive glasses can become therapeutic for specific pathological situations. Calcium-strontium-sodium-zinc-silicate glass bone grafts have been shown to release therapeutic levels of zinc and strontium, however the in vitro compatibility of these materials is yet to be reported. In this study, the in vitro cytocompatibility of three different calcium-strontium-sodium-zinc-silicate glasses was examined as a …


Nonlinear Control Of Facts Controllers For Damping Interarea Oscillations In Power Systems, Mahyar Zarghami, Jagannathan Sarangapani, Mariesa Crow Oct 2010

Nonlinear Control Of Facts Controllers For Damping Interarea Oscillations In Power Systems, Mahyar Zarghami, Jagannathan Sarangapani, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a new nonlinear control of flexible ac transmission systems (FACTS) controllers for the purpose of damping interarea oscillations in power systems. FACTS controllers consist of series, shunt, or a combination of series-shunt devices which are interfaced with the bulk power system through injection buses. Controlling the angle of these buses can effectively damp low frequency interarea oscillations in the system. The proposed control method is based on finding an equivalent reduced affine nonlinear system for the network from which the dominant machines are extracted based on dynamic coherency. It is shown that if properly selected, measurements obtained …


Scale Dependence Of Radar Rainfall Uncertainty: Initial Evaluation Of Nexrad's New Super-Resolution Data For Hydrologic Applications, Bong Chul Seo, Witold F. Krajewski Oct 2010

Scale Dependence Of Radar Rainfall Uncertainty: Initial Evaluation Of Nexrad's New Super-Resolution Data For Hydrologic Applications, Bong Chul Seo, Witold F. Krajewski

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study explores the scale effects of radar rainfall accumulation fields generated using the new super-resolution level II radar reflectivity data acquired by the Next Generation Weather Radar (NEXRAD) network of the Weather Surveillance Radar-1988 Doppler (WSR-88D) weather radars. Eleven months (May 2008-August 2009, exclusive of winter months) of high-density rain gauge network data are used to describe the uncertainty structure of radar rainfall and rain gauge representativeness with respect to five spatial scales (0.5, 1, 2, 4, and 8 km). While both uncertainties of gauge representativeness and radar rainfall show simple scaling behavior, the uncertainty of radar rainfall is …


Optimized Waveform Relaxation Solution Of Electromagnetic And Circuit Problems, Martin J. Gander, Albert E. Ruehli Oct 2010

Optimized Waveform Relaxation Solution Of Electromagnetic And Circuit Problems, Martin J. Gander, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

New algorithms are needed to solve electromagnetic problems using today's widely available parallel processors. In this paper, we show that applying the optimized waveform relaxation approach to a partial element equivalent circuit will yield a powerful technique for solving electromagnetic problems with the potential for a large number of parallel processor nodes.


Uncertainty Quantification Integrated To Cfd Modeling Of Synthetic Jet Actuators, Srikanth Adya, Daoru Frank Han, Serhat Hosder Sep 2010

Uncertainty Quantification Integrated To Cfd Modeling Of Synthetic Jet Actuators, Srikanth Adya, Daoru Frank Han, Serhat Hosder

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Point-Collocation Non-intrusive Polynomial Chaos (NIPC) method has been applied to a stochastic synthetic jet actuator problem used as one of the test cases in the CFDVAL2004 workshop to demonstrate the integration of computationally efficient uncertainty quantification to the high-fidelity CFD modeling of synthetic jet actuators. The test case included the simulation of an actuator generating a synthetic jet issued into quiescent air. The Point-Collocation NIPC method is used to quantify the uncertainty in the long-time averaged u and v-velocities at several locations in the flow field due to the uniformly distributed uncertainty introduced in the amplitude and frequency of …


Coated Steel Rebar For Enhanced Concrete-Steel Bond Strength And Corrosion Resistance, Genda Chen, Jeffery S. Volz, Richard K. Brow, Dongming Yan, Signo Tadeu Dos Reis, Chenglin Wu, Fujian Tang, Charles R. Werner, Xing Tao Sep 2010

Coated Steel Rebar For Enhanced Concrete-Steel Bond Strength And Corrosion Resistance, Genda Chen, Jeffery S. Volz, Richard K. Brow, Dongming Yan, Signo Tadeu Dos Reis, Chenglin Wu, Fujian Tang, Charles R. Werner, Xing Tao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This report summarizes the findings and recommendations on the use of enamel coating in reinforced concrete structures both for bond strength and corrosion resistance of steel rebar. Extensive laboratory tests were conducted to characterize the properties of one- and two-layer enamel coatings. Pseudostatic tests were performed with pullout, beam and column specimens to characterize mechanical properties and develop design equations for the development length of steel rebar in lap splice and anchorage areas. The splice length equation was validated with the testing of large-scale columns under cyclic loading. For corrosion properties, ponding, salt spray, accelerated corrosion, potentiodynamic and electrochemical impedance …


Adaptive Quadrant Filter Based Phase Locked Loop System, L. Shi, Mariesa Crow Sep 2010

Adaptive Quadrant Filter Based Phase Locked Loop System, L. Shi, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Phase-Locked-Loop (PLL) is one of the key technologies extensively used in grid connected power electronics system. A good PLL system can detect the grid phase angle and frequency fast and accurately, and additionally it can extract the positive sequence (or fundamental component for single phase system) exactly. In real applications, source signal (voltage or current) sensed for PLL usually includes harmonic distortion, unbalanced components, noises and frequency variations. Conventional PLL strategy cannot solve all the problems, especially the unbalanced and harmonic distortion. There is a trade-off between the dynamic response and phase angle tracking accuracy. Different PLL solutions are proposed …


Design Of A Conditioner For Smoothing Wind Turbine Output Power, Murali Bottu, Mariesa Crow, A. Curt Elmore Sep 2010

Design Of A Conditioner For Smoothing Wind Turbine Output Power, Murali Bottu, Mariesa Crow, A. Curt Elmore

Electrical and Computer Engineering Faculty Research & Creative Works

As a result of wind speed intermittency, highly variable wind power output can adversely impact local loads. We propose a conditioner to smooth the variable wind power by utilizing the energy of an ultracapacitor. The conditioner is based on a single phase voltage source inverter (VSI) connected between the grid interconnection point and the ultracapacitor. The shunt VSI injects or absorbs active power from the line to smooth the wind power by utilizing the short term storage capabilities of the ultracapacitor. The ultracapacitor is connected to the DC link through a DC-DC converter, which maintains the voltage of the DC …


Hamiltonian Theory Based Coordinated Nonlinear Control Of Generator Excitation And Statcoms, Keyou Wang, Mariesa Crow Sep 2010

Hamiltonian Theory Based Coordinated Nonlinear Control Of Generator Excitation And Statcoms, Keyou Wang, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

A coordinated controller for generator excitation and STATCOMs is studied based on the Hamiltonian function method. The Hamiltonian realization structure for multimachine power systems including STATCOMs is developed leading to a proposed coordinated scheme of excitation control and STATCOM control. Simulation results illustrate the effectiveness of the proposed control strategy.