Engineering Commons^™

Compensation Methods For Demand Response, Zhaofeng Wang

Theses and Dissertations--Electrical and Computer Engineering

Recently, more and more disputations about how demand response should be compensated have arisen. Moreover, the court is about to rehear the Order 745. It probably will have significant impact on the whole working system used to be built for demand response before. Nowadays, some power companies and utilities think that they will endure profits leakage while demand response resources still are compensated.

In this research, knowledge of demand response, local marginal price, Order 745 and other related concept will be explained in detail in case of misunderstanding. Associated with all these knowledge, a possible compensation method will be proposed. …

Nanostructured Semiconductor Device Design In Solar Cells, Hongmei Dang

Theses and Dissertations--Electrical and Computer Engineering

We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS-CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm-550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO₂/ITO-soda lime glass substrates, yield the …

Electron-Beam Patterning Of Teflon Af For Surface Plasmon Resonance Sensing, Mansoor A. Sultan

Theses and Dissertations--Electrical and Computer Engineering

Variable pressure electron beam etching and lithography for Teflon AF has been demonstrated. The relation between dose and etching depth is tested under high vacuum and water vapor. High resolution structures as small as 75 nm half-pitch have been resolved. Several simulation tools were tested for surface plasmon excitation. Grating based dual mode surface plasmon excitation has been shown numerically and experimentally.

A New Islanding Detection Method Based On Wavelet-Transform And Ann For Inverter Assisted Distributed Generator, Zhengyuan Guan

Theses and Dissertations--Electrical and Computer Engineering

Nowadays islanding has become a big issue with the increasing use of distributed generators in power system. In order to effectively detect islanding after DG disconnects from main source, author first studied two passive islanding methods in this thesis: THD&VU method and wavelet-transform method. Compared with other passive methods, each of them has small non-detection zone, but both of them are based on the threshold limit, which is very hard to set. What’s more, when these two methods were applied to practical signals distorted with noise, they performed worse than anticipated.

Thus, a new composite intelligent based method is presented …

Explorations For Efficient Reversible Barrel Shifters And Their Mappings In Qca Nanocomputing, Ke Chen

Theses and Dissertations--Electrical and Computer Engineering

This thesis is based on promising computing paradigm of reversible logic which generates unique outputs out of the inputs and. Reversible logic circuits maintain one-to-one mapping inside of the inputs and the outputs. Compared to the traditional irreversible computation, reversible logic circuit has the advantage that it successfully avoids the information loss during computations. Also, reversible logic is useful to design ultra-low-power nanocomputing circuits, circuits for quantum computing, and the nanocircuits that are testable in nature. Reversible computing circuits require the ancilla inputs and the garbage outputs. Ancilla input is the constant input in reversible circuits. Garbage output is the …

Average-Value Modeling Of Hysteresis Current Control In Power Electronics, Hanling Chen

Theses and Dissertations--Electrical and Computer Engineering

Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control.

In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless …

Single Phase Multilevel Inverter For Grid-Tied Photovoltaic Systems, Martin Edward Prichard

Theses and Dissertations--Electrical and Computer Engineering

Multilevel inverters offer many well-known advantages for use in high-voltage and high-power applications, but they are also well suited for low-power applications. A single phase inverter is developed in this paper to deliver power from a residential-scale system of Photovoltaic panels to the utility grid. The single-stage inverter implements a novel control technique for the reversing voltage topology to produce a stepped output waveform. This approach increases the granularity of control over the PV systems, modularizing key components of the inverter and allowing the inverter to extract the maximum power from the systems. The adaptive controller minimizes harmonic distortion in …

Investigation Of Gate Dielectric Materials And Dielectric/Silicon Interfaces For Metal Oxide Semiconductor Devices, Lei Han

Theses and Dissertations--Electrical and Computer Engineering

The progress of the silicon-based complementary-metal-oxide-semiconductor (CMOS) technology is mainly contributed to the scaling of the individual component. After decades of development, the scaling trend is approaching to its limitation, and there is urgent needs for the innovations of the materials and structures of the MOS devices, in order to postpone the end of the scaling. Atomic layer deposition (ALD) provides precise control of the deposited thin film at the atomic scale, and has wide application not only in the MOS technology, but also in other nanostructures. In this dissertation, I study rapid thermal processing (RTP) treatment of thermally grown …

Hybrid Single And Dual Pattern Structured Light Illumination, Minghao Wang

Theses and Dissertations--Electrical and Computer Engineering

Structured Light Illumination is a widely used 3D shape measurement technique in non-contact surface scanning. Multi-pattern based Structured Light Illumination methods reconstruct 3-D surface with high accuracy, but are sensitive to object motion during the pattern projection and the speed of scanning process is relatively long. To reduce this sensitivity, single pattern techniques are developed to achieve a high speed scanning process, such as Composite Pattern (CP) and Modified Composite Pattern (MCP) technique. However, most of single patter techniques have a significant banding artifact and sacrifice the accuracy. We focus on developing SLI techniques can achieve both high speed, high …

The Constrained Locally Corrected Nyström Method, Nastaran Hendijani

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation a generalization of the locally corrected Nyström (LCN) discretization method is outlined wherein sparse transformations of the LCN system matrix are obtained via singular value decompositions of local constraint matrices. The local constraint matrices are used to impose normal continuity of the currents across boundaries shared by mesh elements. For this reason, the method is called constrained LCN (CLCN).

Due to the CLCN’s simplicity and flexibility, it is straightforward to develop high order CLCN systems for different formulations and mesh element types. As compared to the LCN, the CLCN method offers memory savings and improved accuracy when …

Fault Section Identification For Power Distribution Systems Using Online Measurements, Jie Chen

Theses and Dissertations--Electrical and Computer Engineering

Fault location is very important for distribution systems, and quickly identifying the fault and restoring the system can help reduce the outage time and make the system more reliable. In this thesis, a method for locating faults on distribution systems is introduced to quickly identify the faulted feeder sections by using the overcurrent information from the switches in the system. Fuzzy logic is utilized. The proposed method can quickly and accurately locate faulted sections with different fault locations, fault types and fault resistances. The method is applicable to cases with single-faults or multi-faults, and is applicable to networks with multi-sources. …

Constrained Divergence-Conforming Basis Functions For Method Of Moments Discretizations In Electromagnetics, Robert Pfeiffer

Theses and Dissertations--Electrical and Computer Engineering

Higher-order basis functions are widely used to model currents and fields in numerical simulations of electromagnetics problems because of the greater accuracy and computational efficiency they can provide. Different problem formulations, such as method of moments (MoM) and the finite element method (FEM) require different constraints on basis functions for optimal performance, such as normal or tangential continuity between cells. In this thesis, a method of automatically generating bases that satisfy the desired basis constraints is applied to a MoM formulation for scattering problems using surface integral equations. Numerical results demonstrate the accuracy of this approach, and show good system …

Stargrazer One: A New Architecture For Distributed Maximum Power Point Tracking Of Solar Photovoltaic Sources, Edgard Munoz-Coreas

Theses and Dissertations--Electrical and Computer Engineering

The yield from a solar photovoltaic (PV) source is dependent on factors such as light and temperature. A control system called a maximum power point tracker (MPPT) ensures that the yield from a solar PV source is maximized in spite of these factors. This thesis presents a novel implementation of a perturb and observe (PO) MPPT.

The implementation uses a switched capacitor step down converter and a custom digital circuit implementation of the PO algorithm. Working in tandem, the switched capacitor step down converter and the custom digital circuit implementation were able to successfully track the maximum power point of …

A Methodology Of Spice Simulation To Extract Sram Setup And Hold Timing Parameters Based On Dff Delay Degradation, Xiaowei Zhang

Theses and Dissertations--Electrical and Computer Engineering

SRAM is a significant component in high speed computer design, which serves mainly as high speed storage elements like register files in microprocessors, or the interface like multiple-level caches between high speed processing elements and low speed peripherals. One method to design the SRAM is to use commercial memory compiler. Such compiler can generate different density/speed SRAM designs with single/dual/multiple ports to fulfill design purpose. There are discrepancy of the SRAM timing parameters between extracted layout netlist SPICE simulation vs. equation-based Liberty file (.lib) by a commercial memory compiler. This compiler takes spec values as its input and uses them …

Multifrequency Averaging Of Hysteresis-Current-Controlled Dc-Dc Converters, Yingying Liu

Theses and Dissertations--Electrical and Computer Engineering

Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. Hysteresis current control has fast response and internal current stability through controlling switches to maintain the current within a given hysteresis band of a given current command. However the state space variables in a hysteresis controlled system cannot be directly approached by multifrequency averaging method because of time varing switching frequency. In this thesis, a method of applying multifrequency …

Design Of Energy Storage Controls Using Genetic Algorithms For Stochastic Problems, Si Chen

Theses and Dissertations--Electrical and Computer Engineering

A successful power system in military applications (warship, aircraft, armored vehicle etc.) must operate acceptably under a wide range of conditions involving different loading configurations; it must maintain war fighting ability and recover quickly and stably after being damaged. The introduction of energy storage for the power system of an electric warship integrated engineering plant (IEP) may increase the availability and survivability of the electrical power under these conditions. Herein, the problem of energy storage control is addressed in terms of maximizing the average performance. A notional medium-voltage dc system is used as the system model in the study. A …