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Articles 10801 - 10830 of 21775

Full-Text Articles in Engineering

Orthogonal Loops Probe Design And Characterization For Near-Field Measurement, Tun Li, Yong Cheh Ho, David Pommerenke Aug 2008

Orthogonal Loops Probe Design And Characterization For Near-Field Measurement, Tun Li, Yong Cheh Ho, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field probes are often used to measure the electric and magnetic fields above a printed circuit board in order to identify the sources and coupling paths of an electromagnetic interference (EMI) problem. It is the objective of this paper to propose a rapid E-, Hx- Hy- and circular H-fields measurement using an orthogonal loops probe design. The effects of this probe are analyzed using full-wave simulations and measurements.

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Probes For Diagnosing Emc Problems, Thomas Van Doren Aug 2008

Probes For Diagnosing Emc Problems, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Reconstruction Of Dispersive Dielectric Properties For Pcb Substrates Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, David Pommerenke, Richard E. Dubroff, Zhiping Yang, Wheling Cheng, Konstantin Rozanov, Antonio Orlandi, Giulio Antonini Aug 2008

Reconstruction Of Dispersive Dielectric Properties For Pcb Substrates Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, David Pommerenke, Richard E. Dubroff, Zhiping Yang, Wheling Cheng, Konstantin Rozanov, Antonio Orlandi, Giulio Antonini

Electrical and Computer Engineering Faculty Research & Creative Works

An effective method for extracting parameters of a Debye or a Lorentzian dispersive medium over a wideband frequency range using a genetic algorithm (GA) and a transmission-line model is presented. Scattering parameters (S-parameters) of the transmission-line sections, including a parallel plate, microstrip, and stripline, are measured. Wave equations for TEM/quasi-TEM mode with a complex propagation constant and a frequency-dependent wave impedance are used to evaluate the corresponding S-parameters in an analytical model. The discrepancy between the modeled and measured S-parameters is defined as the objective function in the GA. The GA is used for search of the dispersive-medium parameters by …

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The Repeatability Of System Level Esd Test And Relevant Esd Generator Parameters, Jayong Koo, Qing Cai, David Pommerenke, Kai Wang, John Mass, Masayuki Hirata, Andrew Martwick Aug 2008

The Repeatability Of System Level Esd Test And Relevant Esd Generator Parameters, Jayong Koo, Qing Cai, David Pommerenke, Kai Wang, John Mass, Masayuki Hirata, Andrew Martwick

Electrical and Computer Engineering Faculty Research & Creative Works

Some system level ESD tests do not repeat well if different ESD generators are used. For improving the test repeatability, ESD generator specifications were considered to be changed and a world wide Round Robin test were performed in 2006 to compare the modified and unmodified ESD generators. The test results show the failure level variations up to 1:3 for an EUT among eight different ESD generators. Multiple ESD parameters including discharge currents and transient fields have been measured. This paper tries to find which parameters would predict the failure level the best in general. The transient fields show large variations …

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Aperture Modeling Using A Hybrid Method For Rfi Analysis, Liehui Ren, Zhenwei Yu, Gang Feng, Francesco De Paulis, Yaojiang Zhang, Jun Fan, Xiaopeng Dong, Jason A. Mix, Daniel Hua, Kevin P. Slattery Aug 2008

Aperture Modeling Using A Hybrid Method For Rfi Analysis, Liehui Ren, Zhenwei Yu, Gang Feng, Francesco De Paulis, Yaojiang Zhang, Jun Fan, Xiaopeng Dong, Jason A. Mix, Daniel Hua, Kevin P. Slattery

Electrical and Computer Engineering Faculty Research & Creative Works

A hybrid method is proposed for radio frequency interference (RFI) prediction of a metal enclosure with an aperture on the top wall. The structure is divided into several segments. While the fields in rectangular segments are described by cavity model, the segments with apertures are modeled by the commercial finite element solver (HFSS). Tangential field continuities along the common boundaries of different segments are enforced by the voltages and currents of boundary ports. Good agreement has been achieved between the hybrid method and full wave simulation.

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A Bist Approach For Configurable Nanofabric Arrays, Mandar V. Joshi, Waleed K. Al-Assadi Aug 2008

A Bist Approach For Configurable Nanofabric Arrays, Mandar V. Joshi, Waleed K. Al-Assadi

Electrical and Computer Engineering Faculty Research & Creative Works

This work proposes a Built-in Self Test (BIST) approach to test crossbars for a defined set of faults. The BIST can classify the different programmable elements in the crossbars as non-defective or defective with a certain fault type. The logic synthesis can then configure the crossbar by avoiding these defective elements.

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Advanced Full Wave Esd Generator Model For System Level Coupling Simulation, Qing Cai, Argha Nandy, David Pommerenke, Jong-Sung Lee, Byong-Su Seol, Jayong Koo Aug 2008

Advanced Full Wave Esd Generator Model For System Level Coupling Simulation, Qing Cai, Argha Nandy, David Pommerenke, Jong-Sung Lee, Byong-Su Seol, Jayong Koo

Electrical and Computer Engineering Faculty Research & Creative Works

System level ESD tests can only be performed after hardware is available. Simulating the ESD coupling into a circuit allows at least parametric and quantitative studies of the expected ESD behavior. A complete simulation requires us to model the ESD generator, the passive elements of the DUT and the response of the ICs to injected noise. Having the ultimate objective of combining IC soft error response models with the DUT structure and the ESD generator we report on progresses in modeling the ESD generator and its coupling. The model improves the useful frequency range from a few hundred MHz to …

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Closed-Form Expressions For Determining Approximate Pmc Boundaries Around An Aperture In A Metal Cavity Wall, Francesco De Paulis, Yaojiang Zhang, Jun Fan, Jason A. Mix, Xiaopeng Dong, Daniel Hua, Kevin P. Slattery Aug 2008

Closed-Form Expressions For Determining Approximate Pmc Boundaries Around An Aperture In A Metal Cavity Wall, Francesco De Paulis, Yaojiang Zhang, Jun Fan, Jason A. Mix, Xiaopeng Dong, Daniel Hua, Kevin P. Slattery

Electrical and Computer Engineering Faculty Research & Creative Works

Modern electronic systems may use mixed RF/digital technologies to achieve various functionalities, which leads to various intra-system interference problems including the RF interference from noisy digital circuits to sensitive RF receivers, especially when the overall system is contained in a metal enclosure. A fast method based on a cavity formulation can be used to estimate the internal noise coupling mechanisms inside the enclosure. This method assumes that only the TMz0 mode exists inside the enclosure, i.e., the electric field along the z-direction is constant. The cavity formulation fails in the region adjacent to an aperture in an enclosure wall, since …

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Comparison Of Adaptive Critic-Based And Classical Wide-Area Controllers For Power Systems, Swakshar Ray, Ganesh K. Venayagamoorthy, Balarko Chaudhuri, Rajat Majumder Aug 2008

Comparison Of Adaptive Critic-Based And Classical Wide-Area Controllers For Power Systems, Swakshar Ray, Ganesh K. Venayagamoorthy, Balarko Chaudhuri, Rajat Majumder

Electrical and Computer Engineering Faculty Research & Creative Works

An adaptive critic design (ACD)-based damping controller is developed for a thyristor-controlled series capacitor (TCSC) installed in a power system with multiple poorly damped interarea modes. The performance of this ACD computational intelligence-based method is compared with two classical techniques, which are observer-based state-feedback (SF) control and linear matrix inequality $hbox{LMI-H}^{infty}$ robust control. Remote measurements are used as feedback signals to the wide-area damping controller for modulating the compensation of the TCSC. The classical methods use a linearized model of the system whereas the ACD method is purely measurement-based, leading to a nonlinear controller with fixed parameters. A comparative analysis …

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Glass And Glass-Ceramic Sealant Compositions, Richard K. Brow, Signo Tadeu Dos Reis, Glen Benson Jul 2008

Glass And Glass-Ceramic Sealant Compositions, Richard K. Brow, Signo Tadeu Dos Reis, Glen Benson

Materials Science and Engineering Faculty Research & Creative Works

A glass composition for use as a sealant or otherwise bonded to a fuel cell component, including from about 40 mol % to about 60 mol % RO; from about 2 mol % to about 10 mol % M2O3; and from about 35 mol % to about 45 mol % SiO2. R is selected from the group including strontium, calcium, magnesium and zinc and combinations thereof. M is selected from the group including aluminum, boron, lanthanum, iron and combinations thereof. The glass includes at least about 5 mol % ZnO. Upon heat treatment, the …

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Analytical Study On Rotational Restraint Of Sheathing, Y. Guan Jul 2008

Analytical Study On Rotational Restraint Of Sheathing, Y. Guan

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

No abstract provided.

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Deep Deck And Cellular Deck Diaphragm Strength And Stiffness Evaluation, American Iron And Steel Institute Jul 2008

Deep Deck And Cellular Deck Diaphragm Strength And Stiffness Evaluation, American Iron And Steel Institute

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

No abstract provided.

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Frequency Regulation With Wind Power Plants, Badrul H. Chowdhury, Hong Tao Ma Jul 2008

Frequency Regulation With Wind Power Plants, Badrul H. Chowdhury, Hong Tao Ma

Electrical and Computer Engineering Faculty Research & Creative Works

A new frequency regulation scheme is developed for the wind turbine/generator/converter trio that will provide the capability to participate in restoring frequency in a way similar to the droop response of conventional generators. Output active power adjustment can be realized by both converter and pitch angle control in addition to inertial response of the wind turbine. This helps in maintaining instantaneous power balance as well as in longer term frequency regulation.

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Fresh Self Compacting Concrete, A Shear Thickening Material, Dimitri Feys, Ronny Verhoeven, Geert De Schutter Jul 2008

Fresh Self Compacting Concrete, A Shear Thickening Material, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Literature, the Rheological Properties of Concrete Have Been Investigated Thoroughly, resulting in a Simple Description, in Steady State, by Means of the Bingham Model. Self-Compacting Concrete Shows a Lower Yield Stress, Which in Some Cases is Very Close to Zero, or Can Even Appear to Be Negative When Extrapolating the Bingham Model. in the Latter Case, the Bingham Model is Not Valid and Other Solutions Must Be Found. in This Paper, the Non-Linearity - or Shear Thickening - in the Rheological Behavior of Fresh SCC is Described with the Modified Bingham Model, after the Elimination of Possible Measurement Artefacts. …

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Comparison Of Ultracapacitor Electric Circuit Models, Lisheng Shi, Mariesa Crow Jul 2008

Comparison Of Ultracapacitor Electric Circuit Models, Lisheng Shi, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Due to ultracapacitors' unique features, the electrical performances and reliabilities of electrical systems using ultracapacitors can be improved. It is important to have a good ultracapacitor model for simulation and assisting electrical system design and product development. Several kinds of ultracapacitor models are given these years. Especially, electric circuit models are the interested ones for electrical engineers. This paper concentrates on the electric circuit model. Three basic RC network models are discussed in detail, including modeling ideas, circuit formation, linear/nonlinear factors and evaluations of each model. The general electric circuit model considering the inductance and leakage current effects are given. …

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A Computational Approach To Optimal Damping Controller Design For A Gcsc, Swakshar Ray, Ganesh K. Venayagamoorthy, Edson H. Watanabe Jul 2008

A Computational Approach To Optimal Damping Controller Design For A Gcsc, Swakshar Ray, Ganesh K. Venayagamoorthy, Edson H. Watanabe

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a computational approach for an offline measurement-based design of an optimal damping controller using adaptive critics for a new type of flexible ac transmission system device-the gate-controlled series capacitor (GCSC). Remote measurements are provided to the controller to damp out system modes. The optimal controller is developed based on the heuristic dynamic programming (HDP) approach. Three multilayer-perceptron neural networks are used in the design-the identifier/model network to identify the dynamics of the power system, the critic network to evaluate the performance of the damping controller, and the controller network to provide optimal damping. This measurement-based technique provides …

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Live Wire Segmentation Tool For Osteophyte Detection In Lumbar Spine X-Ray Images, Santosh Seetharaman, R. Joe Stanley, Soumya De, Sameer Antani, L. Rodney Long, George R. Thoma Jul 2008

Live Wire Segmentation Tool For Osteophyte Detection In Lumbar Spine X-Ray Images, Santosh Seetharaman, R. Joe Stanley, Soumya De, Sameer Antani, L. Rodney Long, George R. Thoma

Electrical and Computer Engineering Faculty Research & Creative Works

Computer-assisted vertebra segmentation in x-ray images is a challenging problem. Inter-subject variability and the generally poor contrast of digitized radiograph images contribute to the segmentation difficulty. In this paper, a semi-automated live wire approach is investigated for vertebrae segmentation. The live wire approach integrates initially selected user points with dynamic programming to generate a closed vertebra boundary. In order to assess the degree to which vertebra features are conserved using the live wire technique, convex hull-based features to characterize anterior osteophytes in lumbar vertebrae are determined for live wire and manually segmented vertebrae. Anterior osteophyte discrimination was performed over 405 …

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Plug-In Electric Drive Vehicles: Experiences In Research And Education, Mehdi Ferdowsi Jul 2008

Plug-In Electric Drive Vehicles: Experiences In Research And Education, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper briefly describes the research and educational activities related to a current NSF CAREER grant titled "Vehicle Fleet as a Distributed Energy Storage System for the Power Grid". The PI, Dr. Ferdowsi, is an assistant professor at the Electrical and Computer Engineering Department of the Missouri University of Science and Technology (MST).

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Power Engineering Education: Challenges And Opportunities, Mariesa Crow Jul 2008

Power Engineering Education: Challenges And Opportunities, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a summary of the presentation given at the IEEE Power Engineering Society 2008 General Meeting in the Panel Session "Education of the Power Engineer of the Future." In this paper the author presents the challenges facing the current engineering student and the faculty who teach them. Challenges include declining student interest, volatile job markets, and the changing profile of the power and energy industry.

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Application Of Statcom For Improved Reliability Of Power Grid Containing A Wind Turbine, Aditya P. Jayam, Badrul H. Chowdhury, Nikhil Kumar Ardeshna Jul 2008

Application Of Statcom For Improved Reliability Of Power Grid Containing A Wind Turbine, Aditya P. Jayam, Badrul H. Chowdhury, Nikhil Kumar Ardeshna

Electrical and Computer Engineering Faculty Research & Creative Works

Larger wind farms when integrated to the power system pose stability and control issues. This paper investigates the use of a static synchronous compensator (STATCOM) with wind farms for the purpose of stabilizing the grid voltage after a grid-side disturbance viz., a three phase short circuit fault and load changes. The strategy focuses on a fundamental grid operational requirement to maintain proper voltages at the point of common coupling by regulating the voltage at the collector bus of a wind farm. The DC voltage at individual wind turbine (WT) inverters is also stabilized which facilitates the continuous operation of each …

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A New Contour Reconstruction Approach From Dexel Data In Virtual Sculpting, Kemal Yuksek, Weihan Zhang, Boryslaw Iwo Ridzalski, Ming-Chuan Leu Jul 2008

A New Contour Reconstruction Approach From Dexel Data In Virtual Sculpting, Kemal Yuksek, Weihan Zhang, Boryslaw Iwo Ridzalski, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a novel method of contour reconstruction from dexel data solving the shape anomalies for the complex geometry in virtual sculpting. Grouping and traversing processes are developed to find connectivity between dexels along every two adjacent rays. After traveling through all the rays on one slice, sub-boundaries are connected into full boundaries which are desired contours. The complexity of the new method has been investigated and determined as O(n). We also demonstrate the ability of the described method for viewing a sculpted model from different directions.

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Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing Jul 2008

Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

This paper reports a study on the pH effects on the PtRu nanoparticles synthesized in a polyol process that were deposited on carbon nanotubes (CNTs) by reducing metal salts using ethylene glycol at various pHs. It was found that the nanoparticle size, composition, and catalytic activity all were sensitive to pH. the nanoparticles decreased in size as the preparation pH increased from 1.6 to 10.0, with the largest size at 2.47 nm and the smallest at 1.13 nm. an exception was found for pH at 0.7, which resulted in an average size of only 1.01 nm. Preparation pH was found …

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Nsf Career: Scalable Learning And Adaptation With Intelligent Techniques And Neural Networks For Reconfiguration And Survivability Of Complex Systems, Ganesh K. Venayagamoorthy Jul 2008

Nsf Career: Scalable Learning And Adaptation With Intelligent Techniques And Neural Networks For Reconfiguration And Survivability Of Complex Systems, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The NSF CAREER program is a premier program that emphasizes the importance the foundation places on the early development of academic careers solely dedicated to stimulating the discovery process in which the excitement of research enriched by inspired teaching and enthusiastic learning. This paper describes the research and education experiences gained by the principal investigator and his research collaborators and students as a result of a NSF CAREER proposal been awarded by the power, control and adaptive networks (PCAN) program of the electrical, communications and cyber systems division, effective June 1, 2004. In addition, suggestions on writing a winning NSF …

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Multiple Reference Frame-Based Control Of Three-Phase Pwm Boost Rectifiers Under Unbalanced And Distorted Input Conditions, Peng Xiao, Keith Corzine, Ganesh K. Venayagamoorthy Jul 2008

Multiple Reference Frame-Based Control Of Three-Phase Pwm Boost Rectifiers Under Unbalanced And Distorted Input Conditions, Peng Xiao, Keith Corzine, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Many control algorithms and circuits for three-phase pulse width modulation active rectifiers have been proposed in the past decades. In most of the research, it is often assumed that the input voltages are balanced or contain only fundamental frequency components. In this paper, a selective harmonic compensation method is proposed based on an improved multiple reference frame algorithm, which decouples signals of different frequencies before reference frame transformation. This technique eliminates interactions between the fundamental-frequency positive-sequence components and harmonic and/or negative-sequence components in the input currents, so that fast and accurate regulation of harmonic and unbalanced currents can be achieved. …

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Damping Inter-Area Oscillations By Upfcs Based On Selected Global Measurements, Mahyar Zarghami, Yilu Liu, Jagannathan Sarangapani, Mariesa Crow Jul 2008

Damping Inter-Area Oscillations By Upfcs Based On Selected Global Measurements, Mahyar Zarghami, Yilu Liu, Jagannathan Sarangapani, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a method of using a selected set of the global data for controlling inter-area oscillations of the power network using unified power flow controllers. This novel algorithm utilizes reduced order observers for estimating the missing data the purpose of control when all the data is unavailable through frequency measurements in a wide area control approach. The paper will also address the problem of time-delay in data acquisition through examples.

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Questioning The Metrics For Performance Evaluation, Mariesa Crow Jul 2008

Questioning The Metrics For Performance Evaluation, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper is a summary of the author's presentation in the panel entitled "Publish or Perish: An Evaluation of the Quality, Quantity, Ethics and Review Process of IEEE/PES Publications" given at the IEEE Power Engineering Society 2008 General Meeting. This paper summarizes the publication metrics that are part of the academic performance evaluation of tenure track electrical and computer engineering faculty members at U.S. Institutions. In particular, the performance metrics are discussed relative to promotion criteria.

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A Differential Evolution Approach To Optimal Generator Maintenance Scheduling Of The Nigerian Power System, Yusuf Yare, Ganesh K. Venayagamoorthy Jul 2008

A Differential Evolution Approach To Optimal Generator Maintenance Scheduling Of The Nigerian Power System, Yusuf Yare, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The goal of optimal generator maintenance scheduling is to evolve optimal preventive maintenance schedule of generating units for economical and reliable operation of a power system while satisfying system load demand and crew constraints. In this paper, the differential evolution (DE), an evolutionary computation algorithm that utilizes the differential information to guide its further search, is applied to effectively solve the generator maintenance scheduling (GMS) optimization problem. The proposed method can handle mixed integer discrete continuous optimization problems. Results are presented with the DE algorithm on two different case studies for Nigerian power system.

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A Dstatcom Controller Tuned By Particle Swarm Optimization For An Electric Ship Power System, Pinaki Mitra, Ganesh K. Venayagamoorthy Jul 2008

A Dstatcom Controller Tuned By Particle Swarm Optimization For An Electric Ship Power System, Pinaki Mitra, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

In an all-electric ship power system, the power quality problems mainly arise due to the pulsed loads, which cause the degradation of the overall system performance. The paper proposes the application of DSTATCOM to improve these power quality problems of an electric ship. DSTATCOM is a shunt compensation device, which regulates the bus voltage by injecting reactive power during the pulsed load operations. The control strategy of DSTATCOM plays an important role to meet the objectives. The paper proposes a controller design strategy which is based on particle swarm optimization (PSO). PSO, an algorithm that falls into swarm intelligence family, …

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Self-Tuned Projected Cross Point -- An Improved Current-Mode Control Technique, Kai-Tak Wan, Mehdi Ferdowsi Jul 2008

Self-Tuned Projected Cross Point -- An Improved Current-Mode Control Technique, Kai-Tak Wan, Mehdi Ferdowsi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Self-tuned projected cross point control for power electronic converters is introduced. Projected cross point control (PCPC) combines the advantages of both analog and digital current-mode control techniques. Despite several advantages, accuracy of the PCPC method depends on the power stage inductor value. However, ferromagnetic characteristics of the inductor core material make the inductor measurement inaccurate. Furthermore, the inductor value is subject to change due to temperature variations or other environmental effects. To overcome the dependence of the PCPC method on the inductor value, self- tuned PCPC approach is introduced in this paper. Unlike the conventional PCPC scheme, self-tuned PCPC method …

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A Comparison Of Linear And Nonlinear Statcom Control For Power Quality Enhancement, Atousa Yazdani, Mariesa Crow, Jianjun Guo Jul 2008

A Comparison Of Linear And Nonlinear Statcom Control For Power Quality Enhancement, Atousa Yazdani, Mariesa Crow, Jianjun Guo

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a multilevel STATCOM for electric arc furnace power quality enhancement. An eleven level cascaded multilevel converter is used to alleviate the impacts of an unbalanced arc furnace load. The STATCOM provides a power electronic-based means of embedded control for reactive power support.

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