Electrical and Computer Engineering Commons^™

The Bicycle-Powered Smartphone Charger, Chris Arntzen

Master's Theses

This thesis entails the design and fabrication of a smartphone charger that is powered by a bicycle dynamo hub. In addition to the design and validation of the charger prototype, this thesis involves the testing and characterization of the dynamo hub power source, the design and construction of specialized test equipment, and the design and prototyping of a handlebar-mounted case for the smartphone and charging electronics. With the intention of making the device a commercial product, price, aesthetics, and marketability are of importance to the design. An appropriate description of the charger circuit is a microcontroller-based energy management system, tailored …

Bi-Directional Flyback Dc-Dc Converter For Battery System Of The Dc House Project, Austin J. Luan

Master's Theses

The DC House project strongly relies on renewable energy sources to provide power to the house for various loads. However, when these sources are unable to provide power at a certain time, a back-up energy source from a battery must be readily available to fulfill the house’s power needs. This thesis proposes a bi-directional flyback power converter to allow a single-stage power path to charge the battery from and to discharge the battery to the DC House 48 V system bus. The design, simulation, and hardware prototype of the proposed flyback bi-directional converter will be conducted to demonstrate its feasibility. …

Applied Hw/Sw Co-Design: Using The Kendall Tau Algorithm For Adaptive Pacing, Kenneth W. Chee

Master's Theses

Microcontrollers, the brains of embedded systems, have found their way into every aspect of our lives including medical devices such as pacemakers. Pacemakers provide life supporting functions to people therefore it is critical for these devices to meet their timing constraints. This thesis examines the use of hardware co-processing to accelerate the calculation time associated with the critical tasks of a pacemaker. In particular, we use an FPGA to accelerate a microcontroller’s calculation time of the Kendall Tau Rank Correlation Coefficient algorithm. The Kendall Tau Rank Correlation Coefficient is a statistical measure that determines the pacemaker’s voltage level for heart …

Early Wildfire Detection Using Temporal Filtering And Multi-Band Infrared Analysis, Ansel John Boynton

Master's Theses

Every year wildfires threaten or destroy ecological habitats, man-made infrastructure and people’s lives. Additionally millions of dollars are spent each year trying to prevent and control these fires. Ideally if a wildfire can be detected before it rages out of control it can be extinguished and avoid large scale devastation. Traditional manned fire lookout towers are neither cost effective nor particularly efficient at detecting wildfire. It is proposed that temporal filtering can be used to isolate the signals created at the beginnings of potential wildfires. Temporal filtering can remove any background image and any periodic signals created by the camera …

A Novel Unit Cell Antenna For Highly Integrated Phased Arrays In The Shf Band, Timothy Bryan Ogilvie

Master's Theses

Phased arrays are electromagnetic antenna systems comprised of many radiating elements and processing electronics. Radiating elements are typically positioned in an orderly grid within the antenna aperture. In the receive mode of operation, radiating elements capture some of the signal energy from incoming radiation and guide these signals to processing electronics. Signals are filtered and amplified to maintain the desired sensitivity and complexly weighted using circuits with reconfigurable amplification gain and phase delay. Finally, all signals are combined. The summation of these complexly weighted spatial samples forms a spatial filter in the same way complexly weighted temporal samples establish a …

Modeling And Analysis Of A Dynamic Voltage Regulator, Timothy David Haskell

Master's Theses

Increased government funding and incentives in recent years has led to an increase in the number of grid-tied renewable energy sources as their economic benefits become more renowned. Unfortunately, the outputs of these renewable resources are often highly variable, resulting in undesirable voltage disruptions that are harmful to sensitive loads. In addition to the energy variability of renewable energy sources, random voltage sags, swells and disruptions are already a major issue in power systems. Recent advances in power electronic devices have provided a platform for new solutions to the voltage support problem in power systems. One promising solution is the …

Voltage Stability Analysis Using Simulated Synchrophasor Measurements, Allan Agatep

Master's Theses

An increase in demand for electric power has forced utility transmission systems to continuously operate under stressed conditions, which are close to instability limits. Operating power systems under such conditions along with inadequate reactive power reserves initiates a sequence of voltage instability points and can ultimately lead to a system voltage collapse. Significant research have been focused on time-synchronized measurements of power systems which can be used to frequently determine the state of a power system and can lead to a more robust protection, control and operation performance. This thesis discusses the applicability of two voltage stability synchrophasor-based indices from …

Modeling And Analysis Of A Pv Grid-Tied Smart Inverter's Support Functions, Benjamin Anders Johnson

Master's Theses

The general trends in the past decade of increasing solar cell efficiency, decreasing PV system costs, increasing government incentive programs, and several other factors have all combined synergistically to reduce the barriers of entry for PV systems to enter the market and expand their contribution to the global energy portfolio. The shortcomings of current inverter functions which link PV systems to the utility network are becoming transparent as PV penetration levels continue to increase. The solution this thesis proposes is an approach to control the inverters real and reactive power output to help eliminate the problems associated with PV systems …

Dc, Rf, And Thermal Characterization Of High Electric Field Induced Degradation Mechanisms In Gan-On-Si High Electron Mobility Transistors, Matthew Anthony Bloom

Master's Theses

Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are becoming increasingly popular in power amplifier systems as an alternative to bulkier vacuum tube technologies. GaN offers advantages over other III-V semiconductor heterostructures such as a large bandgap energy, a low dielectric constant, and a high critical breakdown field. The aforementioned qualities make GaN a prime candidate for high-power and radiation-hardened applications using a smaller form-factor. Several different types of semiconductor substrates have been considered for their thermal properties and cost-effectiveness, and Silicon (Si) has been of increasing interest due to a balance between both factors.

In this thesis, the DC, …

A Tunable Electromagnetic Band-Gap Microstrip Filter, Greg A. Lancaster

Master's Theses

In high frequency design, harmonic suppression is a persistent struggle. Non-linear devices such as switches and amplifiers produce unwanted harmonics which may interfere with other frequency bands. Filtering is a widely accepted solution, however there are various shortcomings involved. Suppressing multiple harmonics, if desired, with traditional lumped element and distributed component band-stop filters requires using multiple filters. These topologies are not easily made tunable either. A new filter topology is investigated called Electromagnetic Band-Gap (EBG) structures.

EBG structures have recently gained the interest of microwave designers due to their periodic nature which prohibits the propagation of certain frequency bands. EBG …

Condition-Dependent Risk Assessment Of Large-Scale Grid-Tied Photovoltaic Power Systems, Sherwin Li

Master's Theses

This thesis reviews the methods for evaluating the reliability of large PV systems and techniques for quantifying the impacts of PV interconnection on distribution system reliability. In addition, a comparative study is performed to evaluate the seasonal condition-dependent risk performance of central-inverter and string-inverter grid-tied PV power systems. Major contributions include: 1) risk analysis of seasonal impacts for string and centralized PV systems. Seasonal sensitivities of PV system risks to system structures, temperature variation, solar insolation, and capacitor equivalent series resistance are analyzed; and 2) the incorporation of the effect of operational conditions and the aging failure model into the …

Early Forest Fire Detection Using Texture, Blob Threshold, And Motion Analysis Of Principal Components, Georges Fouad Moussa

Master's Theses

Forest fires constantly threaten ecological systems, infrastructure and human lives. The purpose behind this study is minimizing the devastating damage caused by forest fires. Since it is impossible to completely avoid their occurrences, it is essential to accomplish a fast and appropriate intervention to minimize their destructive consequences. The most traditional method for detecting forest fires is human based surveillance through lookout towers. However, this study presents a more modern technique. It utilizes land-based real-time multispectral video processing to identify and determine the possibility of fire occurring within the camera’s field of view. The temporal, spectral, and spatial signatures of …

Noise Reduction With Microphone Arrays For Speaker Identification, Zachary Gideon Cohen

Master's Theses

The presence of acoustic noise in audio recordings is an ongoing issue that plagues many applications. This ambient background noise is difficult to reduce due to its unpredictable nature. Many single channel noise reduction techniques exist but are limited in that they may distort the desired speech signal due to overlapping spectral content of the speech and noise. It is therefore of interest to investigate the use of multichannel noise reduction algorithms to further attenuate noise while attempting to preserve the speech signal of interest.

Specifically, this thesis looks to investigate the use of microphone arrays in conjunction with multichannel …

Smart Wall Plug Design For The Dc House Project, Edward Constant Sibal

Master's Theses

The DC House project at Cal Poly State University faces a challenge of supplying DC voltage to household appliances. Each appliance in the DC House constitutes a DC load that has a unique voltage and power rating, hence the need to develop a smart DC wall plug that will automatically adjust to the operating voltage required by any DC load. This thesis entails a proof of concept design of the smart DC wall plug which can automatically detect an appliance’s voltage rating. The design employs a dc-dc converter in conjunction with a microcontroller to sense load current to properly adjust …

Radio Direction Finding Network Receiver Design For Low-Cost Public Service Applications, Marcel Colman Eric Stieber

Master's Theses

A low-cost radio direction finding (RDF) VHF receiver has been investigated for development into a radio direction finding network (RDFN) with a particular focus towards public service and commercial asset tracking applications. The primary design criteria were reproducibility, low-cost, and simplicity such that public service and volunteer organizations can benefit from the technology. Two receiver designs were built and tested to allow for comparison of practicality, cost, and accuracy. A pseudo-Doppler RDF and a time difference of arrival (TDOA) receiver were built as proof-of-concept for a system design based on commercial off-the-shelf (COTS) components. The pseudo-Doppler system is a less …

Constant Conduction Angle Biasing For Class C Monolithic Rf Power Amplifiers, Gursewak Singh Rai

Master's Theses

In modern wireless communication systems, a base station typically serves a few hundred users within its cell coverage. To combat the near-far problem – the situation where a nearby user’s strong cellular signal masks the cellular signal of a faraway user – base stations continually enforce power control. That is, nearby users must lower their transmit power. In CDMA technology, power control can be as large as 70-80dB. At low power outputs, this greatly impacts the performance of the RF power amplifier (PA) in the cellular device. For small RF drives, the magnitude of the output RF current approaches the …

Development And Implementation Of A Calibration Procedure For Complex Impedance Spectrum Measurements With Applications To Embedded Battery Health Monitoring And Management Systems, William H. Morrison

Master's Theses

Energy storage devices such as rechargeable Lithium ion batteries are assuming an increasingly prominent role in society, covering applications from electric / hybrid electric vehicles to personal portable electronics. In response to this increasing demand, technologies that monitor battery health and remaining useful life have developed. One such system is the Smart Battery Status Monitor (SBSM), developed by the Idaho National Laboratory, Montana Tech and Qualtech Systems, Inc. The SBSM utilizes impedance spectrum measurements using a subsystem called the Impedance Measurement Box (IMB). The impedance measurements are complex quantities (having both a resistive and a reactive component) and are made …

Active Storage And Ssd Caching In An Object Storage Environment, Michael T. Runde

Master's Theses

The advancing performance and lowering costs required to implement additional processing power on system peripherals such as disk drives are increasingly allowing additional computing ability to be located directly on individual drives. Active Storage attempts to take advantage of this excess by moving some computationally intensive applications directly to the disk drives. This can remove the bottlenecks seen through interconnects between the drives and the CPU of an initiating system as well as remove the need for systems to handle these applications.

The contributions of this thesis are in two areas. The first is the development of a framework designed …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Touchspice Vs. Reactive-Spice: A Human-Computer Interaction Perspective, Joshua Martin O'Hara

Master's Theses

Traditional SPICE simulation tools and applications of circuit theory lack real-time interaction and feedback. The goal of this thesis was to create an interactive physical environment to allow the manipulation and simulation of discrete electrical components in near-real-time while optimizing and streamlining the human-computer interaction (HCI) elements to make the user experience as positive and transparent as possible. This type of HCI and near-real-time simulation feedback would allow for the instant realization of how the parameters of each discrete component or hardware module affect the overall simulation and response of the circuit.

The scope of this thesis is to research, …

Adaptive Energy Management Scheme In Real-Time Energy Harvesting Embedded Systems, Shruti Khare

Master's Theses

The main purpose of this thesis was to develop an online adaptive energy management scheme for energy harvesting embedded systems. Two energy prediction schemes were used, namely Exponentially Weighted Moving Average (EWMA) and Adaptive Forward Prediction (AFP), to schedule all the tasks with least deadline miss rate. The AFP scheme has a mean relative error of 6-10% which is much lower than exponentially weighted moving average (EWMA) algorithm with an error of 30%. The large difference in the error percentage between the two prediction algorithms is due to the adaptive nature of AFP as it tracks small changes in input …

Fabrication And Characterization Of Torsional Micro-Hinge Structures, Mike Madrid Marrujo

Master's Theses

ABSTRACT

Fabrication and Characterization of Torsional Micro-Hinge Structures

Mike Marrujo

There are many electronic devices that operate on the micrometer-scale such as Digital Micro-Mirror Devices (DMD). Micro actuators are a common type of DMD that employ a diaphragm supported by torsional hinges, which deform during actuation and are critical for the devices to have high stability and reliability. The stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. Electrostatically driven micro actuators observe to have a fully recoverable non-linear viscoelastic response. The device consists of a micro-hinge which is suspended by two …

The Effect Of Polarization And Ingan Quantum Well Shape In Multiple Quantum Well Light Emitting Diode Heterostructures, Patrick M. Mcbride

Master's Theses

Previous research in InGaN/GaN light emitting diodes (LEDs) employing semi-classical drift-diffusion models has used reduced polarization constants without much physical explanantion. This paper investigates possible physical explanations for this effective polarization reduction in InGaN LEDs through the use of the simulation software SiLENSe. One major problem of current LED simulations is the assumption of perfectly discrete transitions between the quantum well (QW) and blocking layers when experiments have shown this to not be the case. The In concentration profile within InGaN multiple quantum well (MQW) devices shows much smoother and delayed transitions indicative of indium diffusion and drift during …

Light Extraction Enhancement Of Gan Based Leds Using Top Gratings, Patterned Sapphire Substrates, And Reflective Surfaces, Greg Chavoor

Master's Theses

In the last 15 years, an immense amount of research has gone into developing high efficiency Gallium Nitride based light emitting diodes (LED). These devices have become increasingly popular in LED displays and solid state lighting. Due to the large difference in refractive index between GaN and Air, a significant amount of light reflects at the boundary and does not escape the device. This drawback decreases external quantum efficiency (EQE) by minimizing light extraction. Scientists and engineers continue to develop creative solutions to enhance light extraction. Some solutions include surface roughening, patterned sapphire substrates, and reflective layers.

This study proposes …

Energy Harvesting From Elliptical Machines: Dc-Dc Converter Design Using Sepic Topology, Martin Kou

Master's Theses

Cal Poly’s ongoing Energy Harvesting from Exercise Machines (EHFEM) project is a very convenient and cost-effective way for generating DC power from physical exercise and sending it back to the electrical grid as AC power, providing a renewable energy source for the future. The EHFEM project consists of numerous subprojects involving converting different types of exercise machines for power generation. This project is a continuation of one of the previous subprojects, specifically involving an elliptical machine, and focuses on improving system functionality at different machine settings without altering the elliptical user’s experience by selecting a new DC-DC converter design, while …

Touchspice: Physical-Virtual Circuit Emulator, Kevin Christopher Peters

Master's Theses

This thesis involves the creation of a system of embedded touchscreen devices called touchSPICE to aid in the learning of basic circuits. Traditionally, circuit theory is taught to students in two different methods, lectures and laboratory exercises. Lectures focus on auditory and visual learning and are largely passive learning. Lab experiments allow students to physically interact with the circuits, and learn visually through viewing output waveforms from simulators or on measurement devices. The goal of the touchSPICE project is to develop a physical system for virtual, real-time SPICE simulation that mimics the laboratory experience. In touchSPICE, touchscreen devices act as …

A Proposed Control Solution For The Cal Poly Wind Energy Capture System, Kent R. Burnett

Master's Theses

The focus of this thesis is to research, analyze, and design a reliable and economical control system for the Cal Poly Wind Energy Capture System (WECS). A dynamic permanent magnet generator model is adopted from [1] and [2] and combined with an existing wind turbine model to create a non-linear time varying model in MATLAB. The model is then used to analyze potentially harmful electrical disturbances, and to define safe operating limits for the WECS. An optimal operating point controller utilizing a PID speed loop is designed with combined optimization criteria and the final controller design …

Study Of Statistical And Computational Intelligence Methods Of Detecting Temporal Signature Of Forest Fire Heat Plume From Single-Band Ground-Based Infrared Video, Daniel G. Kohler

Master's Theses

This thesis will analyze video from land-based, cooled mid-wave infrared cameras to identify temporal features indicative of a heat plume from a forest fire. Desirable features and methods will show an ability to distinguish between heat plume movement and other movements, such as foliage, vehicles, humans, and birds in flight. Features will be constructed primarily using combinations of statistics and principal component analysis (PCA) with intent to detect key characteristics of fire and heat plume: persistence and growth. Several classification systems will combine and filter the features in an attempt to classify pixels as either heat or non-heat. The classification …

Real-Time Musical Analysis Of Polyphonic Guitar Audio, John E. Hartquist

Master's Theses

In this thesis, we analyze the audio signal of a guitar to extract musical data in real-time. Specifically, the pitch and octave of notes and chords are displayed over time. Previous work has shown that non-negative matrix factorization is an effective method for classifying the pitches of simultaneous notes. We explore the effect of window size, hop length, and other parameters to maximize the resolution and accuracy of the output.

Other groups have required prerecorded note samples to build a library of note templates to search for. We automate this step and compute the library at run-time, tuning it specifically …

3d Electromagnetic Simulation Tool Exposure For Undergraduate Electrical Engineers: Incorporation Into An Analog Filters Course, Bobby B. Pheng

Master's Theses

With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this …