Engineering Commons^™

Indirect Matrix Converter As Standard Power Electronic Interface, Andrés Escobar-Mejía

Graduate Theses and Dissertations

The increase in the penetration levels of distributed generation in the modern power grid and its importance in future energy systems have accelerated the interest of developing new power electronic interfaces for the energy conversion process. The feasibility of applying the indirect matrix converter as the standard power electronic interface for applications with power ratings from several kW to few MW is addressed in this dissertation. Special attention is given to those applications where space dominates the power electronic requirements. The main motivation for using the indirect matrix converter is that eliminates the energy storage component in the way of …

Photoelectric Characterization Of Bacteriorhodopsin Reconstituted In Lipid Bilayer Membrane, Joel Kamwa

Graduate Theses and Dissertations

The objective of this work was to conduct basic research in biologically inspired energy conversion solutions. A photosynthetic protein (Bacteriorhodopsin) was reconstituted in a bi-layer membrane. Then, when a laser beam was shined on the membrane, the photon energy was used by the protein to pump protons across the membrane. The translocation of protons across the membrane was measured as photocurrent. For this purpose, a system was built to characterize the lipid bilayer membranes and to measure the photocurrent. The lipid bilayer membrane was characterized by its capacitance and resistance. A picoampere photocurrent was observed when Bacteriorhodopsin protein was present …

Metal Assisted Nanowire Growth For Silicon Nanowire/Amorphous Silicon Composite Solar Cell, Asmaa Ali Sadoon

Graduate Theses and Dissertations

Solar cells are photovoltaic devices that convert the energy of light to electricity by the photovoltaic effect. Crystalline silicon-based solar cells are the most dominant solar cells in the market today due to the high efficiency and relatively low cost. However, the cost of such solar cell is still high due to the large amount of material that is consumed in fabricating such a device. Polycrystalline/amorphous thin films and nanomaterial technologies have emerged to reduce the high cost of c-Si based solar cells and increase the efficiency. In this research, we combined these two technologies to propose and fabricate silicon …

Gesn Devices For Short-Wave Infrared Optoelectronics, Benjamin Ryan Conley

Graduate Theses and Dissertations

The electronics industry has a large silicon infrastructure for the manufacture of complementary-metal oxide semiconductor (CMOS) based electronics. The increasing density of Si based circuits has set a pace that is now pushing the physical limits of connectivity between devices over conventional wire based links. This has driven the increasing interest in Si based optoelectronics and to use the groundwork already established by the electronics industry for lower cost optical communications. The greatest limitation to this effort has been the incorporation of a Si based laser, which requires integration of a direct bandgap material within this CMOS process.

The Ge1-xSnx …

Designing And Implementing A Micro-Controller Based Primary-Side Sensing Flyback Converter For Leds Driver, Nam Nhat Tran

Graduate Theses and Dissertations

The fast development of LED and its applications has enabled a new generation of lighting device with higher efficiency and long lifespan. By employing a primary-side sensing flyback converter and the PIC18F micro-controller series, an LED driver could achieve two important features: (1) the compatibility with the available lighting fixtures, and (2) reducing unit price. The flyback converter was chosen for its simplicity, competitive low cost, and its ability to provide a constant output current, a necessarily important factor to an LED driver. Meanwhile, the PIC18F micro-controller series offer numerous advanced features which include but not limited to pulse-width modulation …

Gesn Light-Emitting Devices, Yiyin Zhou

Graduate Theses and Dissertations

Silicon based optoelectronic devices have been investigated for decades. However, due to the indirect band gap nature of Si and Ge, developing of efficient light-emitting source on Si is still a challenging topic. GeSn based optoelectronic devices have the great potential to overcome this deficiency for several reasons. By adding more fraction of Sn into Ge, GeSn band gap could be reduced. The narrowed band gap could be developed for near to mid infrared applications. The alloy can even become the direct band gap material with a large Sn composition (beyond 8%). This feature could enhance the light emission from …

A Phase-Locked Loop In High-Temperature Silicon Carbide And General Design Methods For Silicon Carbide Integrated Circuits, Paul Shepherd

Graduate Theses and Dissertations

Silicon carbide (SiC) has long been considered for integrated circuits (ICs). It offers several advantages, including wider temperature range, larger critical electric field, and greater radiation immunity with respect to Silicon (Si). At the same time, it suffers from challenges in fabrication consistency and lower transconductance which the designer must overcome. One of the recent SiC IC processes developed is the Raytheon High-Temperature Silicon Carbide (HTSiC) complementary MOSFET process. This process is one of the first to offer P channel MOSFETs and, as a result, a greater variety of circuits can be built in it.

The behavior of SiC MOSFETs …

Design Of System Level Control For A Residential Power Router, Fahad Hossain

Graduate Theses and Dissertations

This thesis presents the overall power flow and load management system for a 2 kW residential power router. The objective is to satisfy the residential load demand with cost savings by managing the energy sources including PV, battery, generator, and grid. The power flow management system algorithm is developed both for grid-connected mode and island mode. This algorithm involves the battery state of charge estimation, available PV power, load demand and electricity grid pricing. The residential load management algorithm is also developed using PV power prediction and load power prediction acquired for a day.¬ A Labview GUI is also developed …

The Role Of Quantum Dot Size On The Performance Of Intermediate Band Solar Cells, Najla Alnami

Graduate Theses and Dissertations

The goal of this thesis is to understand possible mechanisms for the reported decrease of the open circuit voltage and solar cell efficiency in quantum dot (QD) intermediate band solar cells (IBSCs). More specifically, the effect of indium arsenide (InAs) QD height on the open circuit voltage and solar cell efficiency was studied in a systematic way. To explore this effect in QD solar cells, several solar cells (SCs) were grown with varying InAs QD heights. All experimental characteristics of the QD solar cells were compared to a reference structure without QDs. All samples were grown by Molecular Beam Epitaxy …

Design, Simulation And Implementation Of Three-Phase Bidirectional Dc-Dc Dual Active Bridge Converter Using Sic Mosfets, Tariq Aldawsari

Graduate Theses and Dissertations

The use of SiC-based martials in fabricating power semiconductor devices has shown more interest than conventional silicon-based. Its promising abilities to improve the performance of power electronic systems made it a valuable choice in building high power DC-DC converters. This thesis presents the design and implementation of a three-phase bidirectional DC-DC Dual Active Bridge using SiC MOSFETs. The proposed circuit is first built in Matlab for simulation analysis. Then a phase shift modulation controller is designed in Simulink to test the simulation circuit. The controls are then integrated through an FPGA to test the prototype. Simulations and experimental results are …

Life Cycle Assessment Projection Of Photovoltaic Cells: A Case Study On Energy Demand Of Quantum Wire Based Photovoltaic Technology Research, Shilpi Mukherjee

Graduate Theses and Dissertations

With increasing clean-energy demand, photovoltaic (PV) technologies have gained attention as potential long-term alternative to fossil fuel energy. However, PV research and manufacture still utilize fossil fuel-powered grid electricity. With continuous enhancement of solar conversion efficiency, it is imperative to assess whether overall life cycle efficiency is also being enhanced. Many new-material PV technologies are still in their research phase, and life cycle analyses of these technologies have not yet been performed. For best results, grid dependency must be minimized for PV research, and this can be accomplished by an analytical instrument called Life Cycle Assessment (LCA).

LCA is the …

Development Of Micro-Hall Devices For Current Sensing, Thomas White

Graduate Theses and Dissertations

In this work, micro-Hall devices were developed for the purpose of sensing current within a high temperature and high power environment. GaAs HEMT, InGaAs pHEMT, and GaN HEMT structures were studied. These structures were grown by molecular beam epitaxy. Processing techniques including photolithography, metallization, Si deposition, wet etching, and dry etching were studied. Electrical characterization measurements including low frequency noise, Hall effect, sensitivity, capacitance-voltage, and current-voltage were performed.

Electron mobility and sheet carrier density studies were performed for both the InGaAs pHEMT and GaAs HEMT structures. Results indicated the InGaAs pHEMT was superior and thus fabricated as the micro-Hall device. …

Design Of A High Performance Silicon Carbide Cmos Operational Amplifier, Shaila Amin Bhuyan

Graduate Theses and Dissertations

This thesis presents the design, simulation, layout and test results of a silicon carbide (SiC) CMOS two-stage operational amplifier (op amp) with NMOS input stage. The circuit has been designed to provide a stable open-loop voltage gain (60 dB), unity-gain bandwidth (around 5 MHz) and maintain a high CMRR and PSRR within a useful input common mode range over process corners and a wide temperature range (25 °C - 300 °C). Between the two stages a Miller compensation topology is placed to improve the phase margin (around 45°). Due to the comparatively high threshold voltage values of transistors in SiC, …

Thermal Analysis, Parasitic Extraction, And Wirebond Reliability Studies Of Power Electronic Modules, Shilpa Prabhudeva

Graduate Theses and Dissertations

This thesis research investigates thermal performance, parasitic extraction and wirebond/encapsulation reliability of power electronic modules. Thermal performance is critical to the power electronic modules. As such, thermal analysis is an important part of the power electronic module design process. Several cases are studied on generalized power modules with a full bridge layout. A database is built based on these results. The studies are performed using SolidWorks thermal simulation tool. The database involves several parameters such as power dissipation, maximum junction temperature, ambient temperature, convection coefficient required to cool the module, size of the baseplate, heat-sink size, substrate size, spacing between …

Technology Mapping, Design For Testability, And Circuit Optimizations For Null Convention Logic Based Architectures, Farhad Alibeygi Parsan

Graduate Theses and Dissertations

Delay-insensitive asynchronous circuits have been the target of a renewed research effort because of the advantages they offer over traditional synchronous circuits. Minimal timing analysis, inherent robustness against power-supply, temperature, and process variations, reduced energy consumption, less noise and EMI emission, and easy design reuse are some of the benefits of these circuits. NULL Convention Logic (NCL) is one of the mainstream asynchronous logic design paradigms that has been shown to be a promising method for designing delay-insensitive asynchronous circuits.

This dissertation investigates new areas in NCL design and test and is made of three sections. The first section discusses …

Optimizing Performance And Scalability On Hybrid Mpsocs, Hongyuan Ding

Graduate Theses and Dissertations

Hardware accelerators are capable of achieving significant performance improvement. But design- ing hardware accelerators lacks the flexibility and the productivity. Combining hardware accelerators with multiprocessor system-on-chip (MPSoC) is an alternative way to balance the flexibility, the productivity, and the performance. However, without appropriate programming model it is still a challenge to achieve parallelism on a hybrid (MPSoC) with with both general-purpose processors and dedicated accelerators. Besides, increasing computation demands with limited power budget require more energy-efficient design without performance degradation in embedded systems and mobile computing platforms. Reconfigurable computing with emerging storage technologies is an alternative to enable the optimization …

Integration Of Energy Storage Into A Future Energy System With A High Penetration Of Distributed Photovoltaic Generation, Arthur K. Barnes

Graduate Theses and Dissertations

Energy storage units (ESU) are increasingly used in electrical distribution systems because they can perform many functions compared with traditional equipment. These include peak shaving, voltage regulation, frequency regulation, provision of spinning reserve, and aiding integration of renewable generation by mitigating the effects of intermittency.

As is the case with other equipment on electric distribution systems, it is necessary to follow appropriate methodologies in order to ensure that ESU are installed in a cost-effective manner and their benefits are realized. However, the necessary methodologies for integration of ESU have not kept pace with developments in both ESU and distribution systems. …

Unbalanced Current Static Compensator, Manuel Antonio Sanchez Tejada

Graduate Theses and Dissertations

The objective of this thesis is to present and evaluate a solution to the unbalanced current issue that can be found in three-phase electrical power grids. The solution is named unbalanced current static compensator (UCSC) and has the goal of balancing the currents at the source in order to mitigate adverse issues such as of negative- and zero-sequence currents that are generated by three-phase current unbalances.

The solution topology consists of three single-phase H-bridge converters that are controlled through an algorithm working in the d-q frame of reference. The algorithm is divided in three different stages: the phase synchronization and …

Electroencephalography(Eeg) Data Collection And Processing Through Machine Learning, Jayshree Desai

Graduate Theses and Dissertations

Machine learning methods are an excellent way for understanding the neural basis of human decision making. Some machine learning systems try to eradicate the need for human intuition in data analysis whereas others embrace a collective approach between humans and machines. The objective of this project is to collect Electroencephalography (EEG) signals through wireless sensors, and the process the collected signals through machine learning methods. The EEG data is collected using three EEG electrodes, each being the positive, negative and ground terminals respectively. Since the signal measures in the unit of micro-volts it needs to be amplified using amplifier circuit. …

Improving Golf Putt Performance With Statistical Learning Of Eeg Signals, Qing Guo

Graduate Theses and Dissertations

In this thesis, a machine learning based method is proposed to predict the putt outcomes of golfers based on their electroencephalogram (EEG) data. The method can be used as a core building block of a brain-computer interface, which is designed to provide guidance to golf players based on their EEG patterns. The proposed method includes three steps. First, multi-channel 1-second EEG trials were extracted during golfers' preparation of putting. Second, different features are calculated such as correlation coefficient, power spectrum density and coherence, which are used as features for the classification algorithm. To predict golfers' performance, the support vector machine …

Optimization Of Plasmon Decay Through Scattering And Hot Electron Transfer, Drew Dejarnette

Graduate Theses and Dissertations

Light incident on metal nanoparticles induce localized surface oscillations of conductive electrons, called plasmons, which is a means to control and manipulate light. Excited plasmons decay as either thermal energy as absorbed phonons or electromagnetic energy as scattered photons. An additional decay pathway for plasmons can exist for gold nanoparticles situated on graphene. Excited plasmons can decay directly to the graphene as through hot electron transfer. This dissertation begins by computational analysis of plasmon resonance energy and bandwidth as a function of particle size, shape, and dielectric environment in addition to diffractive coupled in lattices creating a Fano resonance. With …

Nanofabrication Of Metallic Nanostructures And Integration With Light Detection Devices, Liang Huang

Graduate Theses and Dissertations

Metallic nanostructures have been investigated with various applications especially for integration with light detection devices. The incident light can be manipulated by those nanostructures to enhance light absorption therefor improve device performance. However, previous studies focused on optical design. The electrical properties of these integrated light detection devices have not been fully considered. The photon generated carriers transport and collection are critical for light detection devices as well. An optimized device platform considering from both the optical and electrical aspects to fully utilize these nanostructures is highly desired for future light detection devices.

This dissertation targeted on three objectives, beginning …

Optimum Design Of Spectral Efficient Green Wireless Communications, Gang Wang

Graduate Theses and Dissertations

This dissertation focuses on the optimum design of spectral efficient green wireless communications. Energy efficiency (EE), which is defined as the inverse of average energy required to successfully deliver one information bit from a source to its destination, and spectral efficiency (SE), which is defined as the average data rate per unit bandwidth, are two fundamental performance metrics of wireless communication systems. We study the optimum designs of a wide range of practical wireless communication systems that can either maximize EE, or SE, or achieve a balanced tradeoff between the two metrics. There are three objectives in this dissertation. First, …

Implementation Of Prediction Algorithms To Reduce Latency In Control Of Switching Converters, Brent Bell

Electrical Engineering Undergraduate Honors Theses

Using pulse-width modulation (PWM) to control switching converters such as a dual active bridge introduces latency into a system [1]. Latency in a switching converter decreases the effective bandwidth that the converter can be switched at and for the case of a closed loop control system decreases the effective closed loop system stability. This delay can be attributed to sampling of the control signal and calculation time for the PWM. If a prediction scheme is implemented in this calculation, the next switching time could be predicted to remove any latency. There are effectively two steps in order to achieve this …

Transmission Of Stereo Audio Signals With Lasers, William Austin Curbow

Electrical Engineering Undergraduate Honors Theses

An alternative method for transmitting audio signals via the use of laser technology was presented here. The primary focus of this document is on the audio amplifier subsystem including the design, simulation, and performance results. Simulations using the PSPICE computer simulation software were utilized to investigate the theoretical designs of the audio amplifier subsystem. The audio amplifier was examined in three junctures including the noise-canceling input stage, the high voltage gain cell, and the low impedance driver. Through the design procedure using theoretical calculations, simulations using PSPICE computer software, and examination of the finished product with an oscilloscope, the audio …

Developing A Tool For Generation Of Operational Amplifier Models From Datasheet Parameters, Benjamin Riley Sissons

Electrical Engineering Undergraduate Honors Theses

Due to their flexibility and usefulness operational amplifiers are a very common circuit component that has been in use for over fifty years. Because of their widespread use in circuits there has always been a need for simulation models of the op amp. The purpose of this thesis is to demonstrate the design a tool for use with the modeling software ModLyng that takes several parameters from the datasheet of an op amp and generates a model that can be exported to several popular hardware description languages including Verilog-A and Verilog-AMS. The tool was designed as a plugin for ModLyng …

Fabrication Of Single Nanowire Device Using Electron Beam Lithography, Thach Pham

Graduate Theses and Dissertations

One dimensional nanostructure materials such as nanowires have drawn many interests among the scientific community for a wide range of applications such as field-effect transistors [1], [2], inverters[3], light-emitting diode [1], lasers [4], nanosensors [5], [6], and photodetectors [7]... Comparing with the characterization of nanowire arrays, characterizing a single nanowire will definitely provide a better understanding on new nanowire properties due to simplified behaviors of devices. Although promising theories could be drawn from those results, fabrication of test structure for single nanowire measurements cannot be easily processed using standard microfabrication techniques. Therefore, electron beam lithography integrated with photolithography technique has …

Synthesis And Characterization Of Nanocrystals And Their Application For Photodetectors, Ahmad Nusir

Graduate Theses and Dissertations

Room temperature operation is considered one of the essential restrictions in the design of electronic devices. Photodetectors are unable to detect light efficiently at room temperature due to high dark currents. Semiconductor nanocrystals possess unique optical and electrical properties which make them ideal for fabricating uncooled photodetectors. In this project, nanocrystals were synthesized and implemented in devices that detect light at room temperature.

Nanocrystalline I-III-VI2 and II-VI semiconductors (CuInS2 and CdSe) were grown by a wet chemical method, and characterized using: optical absorption, photoluminescence, Raman scattering, and x-ray diffraction. The optical absorption and photoluminescence spectra of the nanocrystals were recorded …

Broadband Nanostructured Antireflection Coating For Enhancing Inas/Gaas Quantum Dots Solar Cells Performance, Jony C. Sarker

Graduate Theses and Dissertations

The broadband suppression in reflection is one of the primary focuses in high efficiency solar cell research. In this thesis, a moth-eye inspired nanostructure antireflection coating is fabricated on InAs/GaAs quantum dots solar cell in order to enhance the power conversion efficiency. The abrupt refractive index transition between air and GaAs surface is replaced by a tapering zinc oxide nanoneedle on planar tantalum pentoxide coating. The antireflection structure provides gradual reduction of refractive index away from the solar cell top surface.

The nanostructured antireflection coating is fabricated by utilizing chemical bath deposition of tapered zinc oxide nanoneedles on planar tantalum …

High Temperature Ltcc Based Sic Double-Sided Cooling Power Electronic Module, Hao Zhang

Graduate Theses and Dissertations

This objective of this dissertation research is to investigate a module packaging technology for high temperature double-sided cooling power electronic module application. A high-temperature wire-bondless low-temperature co-fired ceramic (LTCC) based double-sided cooling power electronic module was designed, simulated and fabricated. In this module, the conventional copper base plate is removed to reduce the thermal resistance between the device junctions to the heat sink and to improve the reliability of the module by eliminating the large area solder joint between the power substrate and the copper base plate. A low-temperature co-fired ceramic (LTCC) substrate with cavities and vias is used as …