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Electrical and Computer Engineering Faculty Research & Creative Works

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Articles 2611 - 2640 of 3518

Full-Text Articles in Engineering

Series-Parallel Approaches And Clamp Methods For Extreme Dynamic Response With Advanced Digital Loads, Philip T. Krein, Jonathan W. Kimball Aug 2004

Series-Parallel Approaches And Clamp Methods For Extreme Dynamic Response With Advanced Digital Loads, Philip T. Krein, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

The series-input parallel-output dc-dc converter combination provides inherent sharing among the converters. With conventional controls, however, this sharing is unstable. Recent literature work proposes complicated feedback loops to correct the problem, at the cost of dynamic performance. This paper shows that a simple sensorless current mode control stabilizes sharing with fast dynamics suitable for advanced digital loads. With this control in place, a "super-matched" current sharing control emerges. Sharing occurs through transients, limited only by the energy limits of the converters. The control approach has considerable promise for high-performance voltage regulator modules. For even faster response, clamping techniques are proposed.

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Comparison Of Via Equivalent Circuit Model Accuracy Using Quasi-Static And Full-Wave Approaches, Bruce Archambeault, Samuel R. Connor, Jianmin Zhang, James L. Drewniak, Mauro Lai, Antonio Orlandi, Giulio Antonini, Albert E. Ruehli Aug 2004

Comparison Of Via Equivalent Circuit Model Accuracy Using Quasi-Static And Full-Wave Approaches, Bruce Archambeault, Samuel R. Connor, Jianmin Zhang, James L. Drewniak, Mauro Lai, Antonio Orlandi, Giulio Antonini, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

The EMC and signal integrity impact of printed circuit board (PCB) trace discontinuities, such as vias, where the signal is transitioned from one layer to another in the PCB stackup, have become significant recently with the use of very high speed signals in today''s systems. If these discontinuities are ignored, significant distortion of the high speed signal can occur, and in many cases, cause data errors. A fast and accurate technique to include the effect of via discontinuities in the typical design process is needed to ensure this distortion is considered if significant. Therefore, a simple equivalent circuit for the …

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Comparison Of Water And Saltwater Movement In Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, R. Zoughi Aug 2004

Comparison Of Water And Saltwater Movement In Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The presence of chloride ions in steel-reinforced structures leads to the corrosion of the reinforcement thus compromising the integrity and strength of the structure. Thus, it is of great interest to nondestructively detect and evaluate free chloride content in concrete. To this end, an investigation was initiated where two mortar cubes were soaked in distilled water and saltwater solutions, respectively. Their temporal microwave reflection properties were measured using open-ended rectangular waveguides on a daily basis for three cycles, each lasting 35 days. Subsequently, a semiempirical electromagnetic model was developed to simulate the reflection properties of the cubes. The outcome of …

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A Time Domain Approach To Estimate Current Draw From Smt Decoupling Capacitors, Lin Zhang, Bruce Archambeault, Samuel Conner, James L. Knighten, Jun Fan, Norman W. Smith, Ray Alexander, Richard E. Dubroff, James L. Drewniak Aug 2004

A Time Domain Approach To Estimate Current Draw From Smt Decoupling Capacitors, Lin Zhang, Bruce Archambeault, Samuel Conner, James L. Knighten, Jun Fan, Norman W. Smith, Ray Alexander, Richard E. Dubroff, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A time domain approach to investigate and predict impedances and scattering parameters of a DC power bus is proposed. This approach is based on a cavity model and is achieved using a circuit simulation tool - SPICE. A SPICE-based circuit model for triangular power plane segments is described, verified and applied to simulate both the frequency and time domain characteristics of an irregularly shaped two-layer PCB board. Furthermore, the current draw from a surface mount technology (SMT) decoupling capacitor is simulated and estimated using this approach. Near-field electromagnetic loop probes are used to validate the current estimation qualitatively. Additionally the …

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A New Calibration Method For Current Probes, Ramachandran Chundru, David Pommerenke, Sunitha Chandra Aug 2004

A New Calibration Method For Current Probes, Ramachandran Chundru, David Pommerenke, Sunitha Chandra

Electrical and Computer Engineering Faculty Research & Creative Works

EMC engineers often use current probes to detect common mode currents. It is necessary to characterize the probes up to Giga Hertz frequencies. Existing calibration methods for current clamps suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. The proposed method overcomes these disadvantages by directly measuring the current at the center of the current clamp. This paper …

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A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball Aug 2004

A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Often, power electronics systems are simulated with ideal switching elements, perhaps augmented with conduction loss models. A behavioral model is proposed that also includes switching loss and is independent of switching frequency. Therefore, it is suitable for variable frequency control methods, including hysteresis, delta modulation, and random PWM. Models have been realized in Dymola using voltage-controlled voltage sources, current sources, logic, and additional ideal switches. Thermal ports are included to facilitate electro-thermal simulation. A method for parameter extraction is demonstrated using experimental data from standard PWM.

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A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak Aug 2004

A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A three-dimensional subgridding algorithm for the finite difference time domain (FDTD) method is proposed in this paper. The method is based on interpolation of electric and magnetic current densities. The coarse-fine mesh ratio can be either 1:2 or 1:3. Results of a test model utilizing a lossless cavity excited with a dipole show no tendency of instability after 500000 time steps. The reflection in time domain at the subgridding interface was calculated to test the accuracy of the subgridding algorithm.

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Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen Aug 2004

Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen

Electrical and Computer Engineering Faculty Research & Creative Works

A dual-step MTL / FDTD strategy is proposed for anticipating full-vehicle level EMI. In the first step, the current distribution along a cable bundle connecting to electronic modules an an automotive platform is calculated using multi-conductor transmission-line (MTL) models. In order to account for common-mode discontinuities on the vehicle chassis, e.g., slots, 3D full-wave modeling (FDTD) is used to determine radiation impedances, which are thereafter incorporated in the MTL models for compensating the radiation power loss. In the second step, the obtained currents are implemented as impressed current sources in full-vehicle full-wave modeling using an FDTD multi-wire subcelluar algorithm. Thus, …

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Validation Of Equivalent Circuits Extracted From S-Parameter Data For Eye-Pattern Evaluation, Giuseppe Selli, Mauro Lai, Shaofeng Luan, James L. Drewniak, Richard E. Dubroff, Jun Fan, James L. Knighten, Norman W. Smith, Giulio Antonini, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor Aug 2004

Validation Of Equivalent Circuits Extracted From S-Parameter Data For Eye-Pattern Evaluation, Giuseppe Selli, Mauro Lai, Shaofeng Luan, James L. Drewniak, Richard E. Dubroff, Jun Fan, James L. Knighten, Norman W. Smith, Giulio Antonini, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor

Electrical and Computer Engineering Faculty Research & Creative Works

S-parameter circuit model extraction is usually characterized by a trade off between accuracy and complexity. Trading one feature for another may or may not affect the goodness of the reconstructed S-parameter data, which are obtained from frequency domain simulations of the models extracted. However, the ultimate test for the validity of these equivalent circuit representations should be left to eye-diagram simulations, which provide useful insights, from an SI point of view, about the degradation of the signal, as it travels through the system. Physics based simplication procedures can be used to tune the models and achieve less complexity, whereas the …

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A Circuit Approach To Model Narrow Slot Structures In A Power Bus, Lin Zhang, Ray Alexander, Richard E. Dubroff, James L. Drewniak, James L. Knighten, Norman W. Smith, Bruce Archambeault, Samuel R. Connor, Jun Fan Aug 2004

A Circuit Approach To Model Narrow Slot Structures In A Power Bus, Lin Zhang, Ray Alexander, Richard E. Dubroff, James L. Drewniak, James L. Knighten, Norman W. Smith, Bruce Archambeault, Samuel R. Connor, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

A coupled transmission line model for narrow slot structures in DC power planes is proposed. This approach, combined with SPICE-based cavity models and a segmentation method, provides an easy and fast way to model relatively complex structures of power planes with narrow slots often used for isolation purposes. This approach is used to achieve isolation using gapping. The cavity model formulations for rectangular and isosceles right triangular segments are reviewed. The rationale of modeling the narrow slot as a three-conductor transmission line is described. The modeling results are shown and compared with the output of a full wave simulation tool, …

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A Cn-Fdtd Scheme And Its Application To Vlsi Interconnects/Substrate Modeling, Rui Qiang, Dagang Wu, Ji Chen, Chen Wang, James L. Drewniak Aug 2004

A Cn-Fdtd Scheme And Its Application To Vlsi Interconnects/Substrate Modeling, Rui Qiang, Dagang Wu, Ji Chen, Chen Wang, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a two-dimensional (2D) Crank-Nicholason (CN) finite difference time domain (FDTD) method is proposed for VLSI interconnect/substrate characterization. Through rigorous truncation and dispersion error analyses, a guideline on using this technique is presented. Several iterative solvers are investigated to accelerate the solution of the CN-FDTD scheme. Numerical examples are given to demonstrate the accuracy and the efficiency of the proposed algorithm.

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Digital Scr Control Box For Educational Laboratory, Zakdy Sorchini, Jonathan W. Kimball, Philip T. Krein Aug 2004

Digital Scr Control Box For Educational Laboratory, Zakdy Sorchini, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

A "blue box" has been designed to introduce the silicone controlled rectifier (SCR) to power electronics students. SCRs are useful in many real-world applications, and are conceptually important in a student's understanding of power converters. The box is highly flexible in application, and its internal design is simple enough to explain to students. Experiments are shown, both of the type commonly used in the laboratory and of the type used for demonstrations. The box has also been designed to be suitable for research purposes and line voltage applications.

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Microwave Reflection Properties Of Concrete Periodically Exposed To Chloride Solution Of 3% Salinity And Compression Force, Joseph Toby Case, Shanup Peer, Eric Gallaher, R. Zoughi Aug 2004

Microwave Reflection Properties Of Concrete Periodically Exposed To Chloride Solution Of 3% Salinity And Compression Force, Joseph Toby Case, Shanup Peer, Eric Gallaher, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Corrosion of steel rebar in a concrete structure compromises its structural integrity and hence its performance. Chloride intrusion into concrete can lead to depassivation of the steel and initiation of corrosion. Methods exist to detect chlorides in concrete, but the practical use of many of these may be problematic because they are destructive and time consuming, and cannot be used to analyze large structures. Microwave nondestructive evaluation techniques applied to mortar have proven successful for detecting mixture constituents, chloride ingress, and cure-state monitoring. In this paper several concrete samples are cyclically soaked in distilled water and saltwater while also experiencing …

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Extracting R, L, G, C Parameters Of Dispersive Planar Transmission Lines From Measured S-Parameters Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov Aug 2004

Extracting R, L, G, C Parameters Of Dispersive Planar Transmission Lines From Measured S-Parameters Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov

Electrical and Computer Engineering Faculty Research & Creative Works

Signal integrity (SI) analysis of printed circuit boards for high-speed digital design requires information on the perunit-length R, L, G, C parameters of the transmission lines. However, these are not always available when the property of the dielectric medium used in the board is unknown. A method to extract R, L, G, and C parameters from parallel-plate and strip transmission line geometries is proposed. It is based on measured scattering parameters and analytical modeling. A genetic algorithm (GA) is used to optimize the extraction by minimizing the frequency domain discrepancy between an objective function, which is the measured scattering matrix …

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Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires Aug 2004

Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires

Electrical and Computer Engineering Faculty Research & Creative Works

Radiated emission algorithms for a printed circuit board EMC expert system are described. The expert system mimics the thinking processes that human EMC engineers would use to analyze circuit boards and make design recommendations. Working with limited information about the enclosure, cables or the exact nature of the signals, the expert system evaluates different structures on the printed circuit board looking for potentially strong radiated emission sources. Results obtained from the analysis of a sample printed circuit board are provided to demonstrate how the expert system quickly identifies problems that would otherwise be difficult to locate.

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Extraction Of A Spice Via Model From Full-Wave Modeling For Differential Signaling, Shaofeng Luan, Giuseppe Selli, James L. Drewniak, Andrea De Luca, Giulio Antonini, Antonio Orlandi, Antonio Ciccomancini Scogna, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander Aug 2004

Extraction Of A Spice Via Model From Full-Wave Modeling For Differential Signaling, Shaofeng Luan, Giuseppe Selli, James L. Drewniak, Andrea De Luca, Giulio Antonini, Antonio Orlandi, Antonio Ciccomancini Scogna, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a procedure for building SPICE models for via transitions in differential signaling. The method of extracting parameters of SPICE models from a full-wave simulation tool is demonstrated. Then the validity of the SPICE models is studied by comparing the solution from the SPICE models with that from the full-wave simulation.

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Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi Aug 2004

Extraction Of Spice-Type Equivalent Circuits Of Signal Via Transitions Using The Peec Method, Jingkun Mao, James L. Drewniak, Giulio Antonini, Antonio Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

Digital devices and discontinuities are typically analyzed by inserting their equivalent circuits into SPICE-type simulators. The partial element equivalent circuit method has been proven to be very useful for electromagnetic modeling. It can be used in both the time and the frequency domain. In this paper, the PEEC technique is employed as an efficient full-wave modeling tool to derive SPICE-type equivalent circuits of signal via transition structures. A nodal analysis technique is utilized in conjunction with the optimization algorithm to extract the equivalent circuits, whose component values are the parameters optimized. The good agreement between different approaches demonstrates that the …

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Effects Of Open Stubs Associated With Plated Through-Hole Vias In Backpanel Designs, Shaowei Deng, Jingkun Mao, Todd H. Hubing, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander, Chen Wang Aug 2004

Effects Of Open Stubs Associated With Plated Through-Hole Vias In Backpanel Designs, Shaowei Deng, Jingkun Mao, Todd H. Hubing, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander, Chen Wang

Electrical and Computer Engineering Faculty Research & Creative Works

Plated through-hole (PTH) vias are commonly used in printed circuit boards. They usually leave open stubs if the signal(s) does not transition the entire depth of the board. These open stubs can have a negative impact on signal transmission. This summary reports the investigation of the impact of the open via stubs in a typical backpanel design.

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Representation Of Permittivity For Multiphase Dielectric Mixtures In Fdtd Modeling, Marina Koledintseva, J. Wu, H. Zhang, James L. Drewniak, Konstantin Rozanov Aug 2004

Representation Of Permittivity For Multiphase Dielectric Mixtures In Fdtd Modeling, Marina Koledintseva, J. Wu, H. Zhang, James L. Drewniak, Konstantin Rozanov

Electrical and Computer Engineering Faculty Research & Creative Works

A simple method of approximating frequency characteristics of composites in a form convenient for time-domain numerical modeling is proposed. The frequency characteristics can be obtained from experiment or calculations based on the Maxwell Garnett mixing formalism. The resultant frequency characteristic might be of a complex shape corresponding to a combination of a number of absorption peaks. The approximation is made by a series of Debye-like terms using a genetic algorithm (GA). This leads to the necessity of taking a number of terms in the approximating series. Every term corresponds to its pole, i.e., the frequency where the maximum loss occurs. …

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Static And Quasi-Dynamic Load Balancing In Parallel Fdtd Codes For Signal Integrity, Power Integrity, And Packaging Applications, Sarah A. Seguin, Michael A. Cracraft, James L. Drewniak Aug 2004

Static And Quasi-Dynamic Load Balancing In Parallel Fdtd Codes For Signal Integrity, Power Integrity, And Packaging Applications, Sarah A. Seguin, Michael A. Cracraft, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The Finite-Difference Time-Domain (FDTD) method is a robust technique for calculating electromagnetic fields, but practical problems, involving complex or large geometries, can require a long time to calculate on any one single-processor computer. One computer with many processors or many single-processor computers can reduce the computation time. However, some FDTD cell types, e.g., PML cells, require more computation time than others. Thus, the size and shape of the individual process allocations can significantly influence the computation time. This paper addresses these load balancing issues with static and quasi-dynamic approaches. The Message-Passing Interface (MPI) library is applied to a three-dimensional (3D) …

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The Design Of A Lumped Element Impedance-Matching Network With Reduced Parasitic Effects Obtained From Numerical Modeling, Shaofeng Luan, Jun Fan, James L. Knighten, Norman W. Smith Aug 2004

The Design Of A Lumped Element Impedance-Matching Network With Reduced Parasitic Effects Obtained From Numerical Modeling, Shaofeng Luan, Jun Fan, James L. Knighten, Norman W. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an impedance-matching network design with numerical modeling of the parasitic effects. A modeling tool CEMPIE (a Circuit Extraction approach based on a Mixed Potential Integral Equation formulation) is used to model the hoard-level parasitics of surface mount technology (SMT) resistors for impedance-matching networks. A 3-layer design of impedance-matching network with 0402 SMT resistors is implemented according to the modeling results. And its performance is demonstrated.

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An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke Aug 2004

An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Time-domain simulation algorithms are widely used in the anaylsis and design of electromagnetic systems. Many of them are characterized by high Q's. Thus, the simulations have to employ many time steps in order to achieve a complete characterization of these systems. This time-consuming computational effort can be avoided if the late instants of time are extrapolated by applying a parametric estimation algorithm. An optimized implementation of a time-domain extrapolation method and a stop criterion are discussed in this paper. The latter criterion is based upon a normalized squared difference between the waveforms extrapolated from two different sets of initial data …

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Defect Characterization And Yield Analysis Of Array-Based Nanoarchitecture, Shanrui Zhang, Minsu Choi, Nohpill Park Aug 2004

Defect Characterization And Yield Analysis Of Array-Based Nanoarchitecture, Shanrui Zhang, Minsu Choi, Nohpill Park

Electrical and Computer Engineering Faculty Research & Creative Works

With molecular-scale materials and fabrication techniques recently developed, high-density computing systems in nanometer domain emerge. An array-based nanoarchitecture has been recently proposed based on nanowires such as carbon nanotubes (CNTs), silicon nanowires (SiNWs). High-density nanoarray-based systems consisting of nanometer-scale elements are likely to have many imperfections; thus, defect-tolerance is considered as one of the most significant challenges. In this paper, we propose a probabilistic yield model for the array-based nanoarchitecture. The proposed yield model can be used 1) to accurately estimate the raw and net array densities, and 2) to design and optimize more defect and fault-tolerant systems based on …

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A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya Jul 2004

A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a framework of a system for the query and retrieval of video data based on video events in huge video repositories. the events are formulated using domain-independent event primitives which are represented by spatio-temporal relationships between objects in the video scenes. Complex events are expressible as combinations of simpler events. This facilitates support of event queries from a variety of points of view. in addition, the framework is expected to provide adaptability of the framework to multiple domains.

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Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy Jul 2004

Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy

Electrical and Computer Engineering Faculty Research & Creative Works

Motion estimation is an important component in video compression schemes which impacts the encoder performance and the quality of the reconstructed video sequence. Block-Based techniques are the most popular among the several motion estimation techniques used in practice due to their simplicity allowing efficient hardware implementations. the quality of motion predicted frame and the speed of motion vector computation are the primary measures of performance of motion estimation schemes. the video compression standards only specify the syntax of the bitstream and not any specifics of the motion estimation techniques. Thus, the knowledge of the workings and performance of commonly used …

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Estimation Of Heart-Surface Potentials Using Regularized Multipole Sources, Daryl G. Beetner, R. Martin Arthur Jul 2004

Estimation Of Heart-Surface Potentials Using Regularized Multipole Sources, Daryl G. Beetner, R. Martin Arthur

Electrical and Computer Engineering Faculty Research & Creative Works

Direct inference of heart-surface potentials from body-surface potentials has been the goal of most recent work on electrocardiographic inverse solutions. We developed and tested indirect methods for inferring heart-surface potentials based on estimation of regularized multipole sources. Regularization was done using Tikhonov, constrained-least-squares, and multipole-truncation techniques. These multipole-equivalent methods (MEMs) were compared to the conventional mixed boundary-value method (BVM) in a realistic torso model with up to 20% noise added to body-surface potentials and ±1 cm error in heart position and size. Optimal regularization was used for all inverse solutions. The relative error of inferred heart-surface potentials of the MEM …

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Neural Network Stabilizing Control Of Single Machine Power System With Control Limits, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow Jul 2004

Neural Network Stabilizing Control Of Single Machine Power System With Control Limits, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers are widely used to generate supplementary control signals for the excitation system in order to damp out the low frequency oscillations. This paper proposes a stable neural network (NN) controller for the stabilization of a single machine infinite bus power system. In the power system control literature, simplified analytical models are used to represent the power system and the controller designs are not based on rigorous stability analysis. This work overcomes the two major problems by using an accurate analytical model for controller development and presents the closed-loop stability analysis. The NN is used to approximate the …

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Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant Jul 2004

Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant

Electrical and Computer Engineering Faculty Research & Creative Works

Most existing power supplies for induction heating equipment produce voltage at a single (adjustable) frequency. Recently, however, induction heating power supplies that produce voltage at two (adjustable) frequencies have been researched and even commercialized. Dual-frequency power supplies are a significant development for heat-treating workpieces with uneven geometries, such as gears, since different portions of such workpieces are heated dissimilarly at a single frequency and so require a two step process using a single-frequency power supply. On the other hand, a dual-frequency power supply can achieve the desired result for such workpieces in a one step process. This paper proposes the …

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Small Local Dynamic Fuzzy Logical Models For Large-Scale Power Systems, Jianjun Guo, Levent Acar, Badrul H. Chowdhury, Mariesa Crow Jun 2004

Small Local Dynamic Fuzzy Logical Models For Large-Scale Power Systems, Jianjun Guo, Levent Acar, Badrul H. Chowdhury, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In the power system stability problems the primary actors in the mathematical system model are the differential equations defining the dynamic state variables of generation and load. These differential equations are coupled together by load flow equations. Mathematically the load flow equations are nonlinear algebraic equations. These differential equations and nonlinear algebraic equations form the mathematical Differential Algebraic Equations (DAE) model for the power system. The fuzzy set theory is commonly used in analysis of dynamical nonlinear systems. In this paper, we build a set of local dynamical fuzzy logic models for the differential equations, thus transforming the differential equations …

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Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar Jun 2004

Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

A scale model of a tractor-trailer truck was developed as a testbed for control algorithms. The truck operates in autonomous or semi-autonomous modes. An on-board Pentium computer with a PC104 bus performs the computations and data collection. Various sensors and a wireless transceiver are on-board the truck. Our research focus has been in the autonomous control of vehicles using intelligent systems. For this document we have employed a multi-resolutional hierarchy to plan a path for the tractor-trailer truck. The hierarchy starts with a simple path then warps it around obstacles. The modular construction of the hierarchy allows more intelligent agents …

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