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Full-Text Articles in Engineering
Implementation Of Static And Semi-Static Versions Of A 24+8x8 Quad-Rail Null Convention Multiply And Accumulate Unit, R. Sankar, V. Kadiyala, S. Kumar, S. Mohan, F. Kacani, Waleed K. Al-Assadi, Scott C. Smith, Ravi Bonam
Implementation Of Static And Semi-Static Versions Of A 24+8x8 Quad-Rail Null Convention Multiply And Accumulate Unit, R. Sankar, V. Kadiyala, S. Kumar, S. Mohan, F. Kacani, Waleed K. Al-Assadi, Scott C. Smith, Ravi Bonam
Electrical and Computer Engineering Faculty Research & Creative Works
This paper focuses on implementing a 2s complement 8x8 dual-rail bit-wise pipelined multiplier using the asynchronous null convention logic (NCL) paradigm. The design utilizes a Wallace tree for partial product summation, and is implemented and simulated in VHDL, the transistor level, and the physical level, using a 1.8V 0.18mum TSMC CMOS process. The multiplier is realized using both static and semi-static versions of the NCL gates; and these two implementations are compared in terms of area, power, and speed.
A Neural Network Based Optimal Wide Area Control Scheme For A Power System, Ganesh K. Venayagamoorthy, Swakshar Ray
A Neural Network Based Optimal Wide Area Control Scheme For A Power System, Ganesh K. Venayagamoorthy, Swakshar Ray
Electrical and Computer Engineering Faculty Research & Creative Works
With deregulation of the power industry, many tie lines between control areas are driven to operate near their maximum capacity, especially those serving heavy load centers. Wide area control systems (WACSs) using wide-area or global signals can provide remote auxiliary control signals to local controllers such as automatic voltage regulators, power system stabilizers, etc to damp out inter-area oscillations. This paper presents the design and the DSP implementation of a nonlinear optimal wide area controller based on adaptive critic designs and neural networks for a power system on the real-time digital simulator (RTDS©). The performance of the WACS as a …
A Reconfigurable Facts System For University Laboratories, Liangying Dong, Zhiping Yang, Shen Chen, Lin Zhang, Stan Atcitty, Mariesa Crow
A Reconfigurable Facts System For University Laboratories, Liangying Dong, Zhiping Yang, Shen Chen, Lin Zhang, Stan Atcitty, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
To fully understand the dynamic performance of the multiple flexible ac transmission systems (FACTS) devices, a hardware setup is needed to complement software simulation for university research laboratories. This paper presents the schematic and basic controls of a reconfigurable FACTS system that can be used to realize the major voltage-sourced-converter FACTS topologies: the StatCom, the static synchronous series compensator (SSSC), and the unified power-flow controller (UPFC). Furthermore, the state models and control algorithms for the FACTS devices are proposed. The digital signal processor (DSP)-based control system enables new control methods to be rapidly implemented. The comparison of the experimental and …
An Improved Pnlms Algorithm, J. Benesty, Steven L. Grant
An Improved Pnlms Algorithm, J. Benesty, Steven L. Grant
Electrical and Computer Engineering Faculty Research & Creative Works
The proportionate normalized least mean square (PNLMS) algorithm was developed for use in network echo cancelers. In comparison to the normalized least mean square (NLMS) algorithm, PNLMS has a very fast initial convergence and tracking when the echo path is sparse. Unfortunately, when the impulse response is dispersive, the PNLMS converges much slower than NLMS. This implies that the rule proposed in PNLMS is far from optimal. In many simulations, it seems that we fully benefit from PNLMS only when the impulse response is close to a delta function. We propose a new rule that is more reliable than the …
Second-Order Statistical Properties Of The Wss Jakes' Fading Channel Simulator, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu
Second-Order Statistical Properties Of The Wss Jakes' Fading Channel Simulator, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu
Electrical and Computer Engineering Faculty Research & Creative Works
An improved Jakes' (1994) fading channel simulator was proposed by Pop and Beaulieu (see ibid., vol.49, p.699-708, Apr. 2001) to eliminate the stationarity problem occurring in Jakes' original design. In this paper, second-order statistical properties of the improved Jakes' simulator are analyzed. Consistent with Pop and Beaulieu's caution about high-order statistics of the simulator, it is proved that some second-order statistics of both the quadrature components and the envelope do not match the desired ones even if the number of sinusoids approaches infinity. Therefore, care must be taken when the simulator is employed to evaluate algorithms and systems.
A New Control Strategy For The Unified Power Flow Controller, Lin Zhang, Liangying Dong, Mariesa Crow
A New Control Strategy For The Unified Power Flow Controller, Lin Zhang, Liangying Dong, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
The unified power flow controller (UPFC) is the most versatile among a variety of flexible AC transmission system (FACTS) devices, which can be used for power flow control, enhancement of transient stability, damping system oscillations and voltage regulation. In this paper, we propose a new PI based approach for the dynamic control of UPFC. With the new control strategy, not only the active and reactive power flow control but also the system oscillations damping can be achieved. The digital simulation results developed in MATLAB and PSCAD/EMTDC environments are presented to verify the efficiency of the proposed control algorithm.
Fault Classification Using Kohonen Feature Mapping, Badrul H. Chowdhury, Kunyu Wang
Fault Classification Using Kohonen Feature Mapping, Badrul H. Chowdhury, Kunyu Wang
Electrical and Computer Engineering Faculty Research & Creative Works
Applications of neural networks to power system fault diagnosis have provided positive results and shown advantages in process speed over conventional approaches. This paper describes the application of a Kohonen neural network to fault detection and classification using the fundamental components of currents and voltages. The Electromagnetic Transients Program is used to obtain fault patterns for the training and testing of neural networks. Accurate classifications are obtained for all types of possible short circuit faults on test systems representing high voltage transmission lines. Short training time makes the Kohonen network suitable for on-line power system fault diagnosis. The method introduced …
Fdtd Modeling Of Thin Wires For Simulating Common-Mode Radiation From Structures With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Fdtd Modeling Of Thin Wires For Simulating Common-Mode Radiation From Structures With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren
Electrical and Computer Engineering Faculty Research & Creative Works
The analysis of shielding enclosures is complicated by the existence of apertures and cables. The finite-difference time-domain (FDTD) method can model shielding enclosures with complex geometries, but has difficulty modeling wires and cables of arbitrary radii. Modeling the wire by setting the axial component of the electric field to zero in the FDTD results in a wire with a radius determined by the mesh discretisation. Neglecting wire radius in applications such as electromagnetic interference (EMI) or printed circuit board modeling may result in gross errors because near field quantities are typically sensitive to wire thickness. Taflove (1990) developed a wire …
The Multirate Simulation Of Facts Devices In Power System Dynamics, J. G. Chen, Mariesa Crow
The Multirate Simulation Of Facts Devices In Power System Dynamics, J. G. Chen, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the multirate method is applied to the problem of simulating the dynamics of a power system which contains fast components such as induction machine loads and FACTS devices. Results concerning the numerical stability and accuracy of the multirate method are presented. Implementation concerns are also addressed by studying an example power system which contains a wide range of time response behavior
Analysis Of A Current-Regulated Brushless Dc Drive, Keith Corzine, S. D. Sudhoff, H. J. Hegner
Analysis Of A Current-Regulated Brushless Dc Drive, Keith Corzine, S. D. Sudhoff, H. J. Hegner
Electrical and Computer Engineering Faculty Research & Creative Works
Current-regulated brushless DC machines are used in a wide variety of applications including robotics, actuators, electric vehicles, and ship propulsion systems. When conducting system analysis of this or any other type of drive, average-value reduced-order models are invaluable since they provide a means of rapidly predicting the electromechanical dynamics and are readily linearized for control system synthesis. In this paper, a highly accurate average-value reduced-order model of a hysteresis current-regulated brushless DC drive is set forth. In so doing it is demonstrated that the drive exhibits five distinct operating modes. The physical cause of each of these modes is explained …
A Flux-Weakening Strategy For Current-Regulated Surface-Mounted Permanent-Magnet Machine Drives, Keith Corzine, S. D. Sudhoff, H. J. Hegner
A Flux-Weakening Strategy For Current-Regulated Surface-Mounted Permanent-Magnet Machine Drives, Keith Corzine, S. D. Sudhoff, H. J. Hegner
Electrical and Computer Engineering Faculty Research & Creative Works
Permanent-magnet synchronous machines fed from current-regulated converters feature nearly ideal performance at low-to-moderate speeds. However, as rotor speed increases the back emf rises which results in loss of current regulation and decreased torque. In buried-magnet machine drives, flux weakening is often used to extend the speed range. This paper sets forth a flux-weakening control specifically designed for surface-mounted permanent-magnet machines which is simple and does not require knowledge of the machine or system parameters. The proposed method is demonstrated both experimentally and through the use of computer simulation
The Multirate Method For Simulation Of Power System Dynamics, J. G. Chen, Mariesa Crow
The Multirate Method For Simulation Of Power System Dynamics, J. G. Chen, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the multirate method is introduced to analyse power system behavior for systems with widely varying time constants. Estimates for computational speed-up are derived based on a linear system approach. The method is applied to a small power system example and the results, both in terms of accuracy and computation time, are compared to traditional simulation methods
Simulation Of Communication Systems, William H. Tranter, Kurt Louis Kosbar
Simulation Of Communication Systems, William H. Tranter, Kurt Louis Kosbar
Electrical and Computer Engineering Faculty Research & Creative Works
When both a complex system and a complex channel model are encountered, the result is typically a design or analysis problem that cannot be solved using traditional (pencil and paper) mathematical analysis. Computer-aided techniques, which usually involve some level of numerical simulation, can be a very valuable tool in these situations. The purpose of this article is to provide a tutorial review of some of the basic techniques of communication system simulation. The authors consider the basic techniques used to represent signals, generate signals, and model linear systems, nonlinear systems, and time-varying systems within a simulation. They consider the important …
Interval Estimation And Monte Carlo Simulation Of Digital Communication Systems, Kurt Louis Kosbar, T. F. Chang
Interval Estimation And Monte Carlo Simulation Of Digital Communication Systems, Kurt Louis Kosbar, T. F. Chang
Electrical and Computer Engineering Faculty Research & Creative Works
This work quantifies the accuracy of bit error rate (BER) estimates produced by Monte Carlo simulations by carefully applying confidence interval estimation techniques. Due to numerical difficulties, some previous work in this area has assumed that the BER statistic possessed a Gaussian distribution. This work demonstrates that in some important regions the estimate is decidedly non-Gaussian, and application of central limit theorem arguments can result in errors in excess of an order of magnitude. This work investigates the accuracy of common approximations and the feasibility of exact calculation of confidence intervals, and presents a novel polynomial class approximation. By combining …
Optimizing The Integration Of Photovoltaic Systems With Electric Utilities, Badrul H. Chowdhury
Optimizing The Integration Of Photovoltaic Systems With Electric Utilities, Badrul H. Chowdhury
Electrical and Computer Engineering Faculty Research & Creative Works
The author introduces a comprehensive simulation package whereby the optimal size, operation, performance and economics of a photovoltaic (PV) system can be determined in the utility-integrated mode. The central issue is to present a single definitive optimization model. A stepwise analytical methodology starting at the solar resource and culminating in the value of the PV system in terms of avoided costs is provided. The methodology includes processing of the solar irradiance; identification of the PV system''s configuration and operational features; identification of real-time system controls in the presence of PV generation; security assessment in the presence of PV and production …
The Parallel Implementation Of The Waveform Relaxation Method For The Simulation Of Structure-Preserved Power Systems, Marija D. Ilić, Mariesa Crow
The Parallel Implementation Of The Waveform Relaxation Method For The Simulation Of Structure-Preserved Power Systems, Marija D. Ilić, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
Several results pertaining to the partitioning of the waveform relaxation (WR) algorithm for dynamic simulation are presented. The WR algorithm is extended to a structure-preserving power system model in which the loads are retained. This results in a system of differential/algebraic equations (DAEs). Power systems are shown to exhibit several dynamic characteristics which make them suitable for simulation by the WR method. A heuristic method for determining a fault-dependent partitioning of the power system for parallel implementation is given.
The Parallel Implementation Of The Waveform Relaxation Method For Transient Stability Simulations, Marija D. Ilić, Mariesa Crow
The Parallel Implementation Of The Waveform Relaxation Method For Transient Stability Simulations, Marija D. Ilić, Mariesa Crow
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the authors extend the results of their earlier paper on waveform relamtion (WR), which is a parallel algorithm for transient stability analysis. The WR algorithm is extended to a structure-preserving power system model in which the loads are retained. This results in a system of differential/ algebraic equations (DAEs). Power systems exhibit several unique dynamic properties which may be exploited in an advantageous manner by the WR algorithm. This leads to a greater computational efficiency than most other direct methods of simulation. This paper presents several theoretical results as well as computational results on parallel implementation.