In cellular telephones, RF power amplifiers consume a significant part of the total phone current. Reducing the average PA current will extend battery life. In GSM systems the handset is commanded by the base station to transmit at power levels lower than full power much of the time. A Doherty...
Determining the performance characteristics of various ocean wave energy converters (OWEC) has proven to be difficult due to problems replicating a baseline motion profile in the ocean or wave tank to compare these devices. The linear test bed seeks to mechanically simulate the relative linear motion between the active components...
Environmental concerns have renewed the interest in electric vehicles. To gain
widespread use, electric vehicles will also have to offer good performance and be
reasonably priced. AC drive systems using modern semiconductors can provide
efficient operation at the required power levels, but their cost at present is still too
high....
Ocean wave energy is rapidly becoming a field of great interest in the world of renewable energy. Significant advancements in design and technology are being made to make wave energy a viable alternative for our growing energy demands. The two major hurdles for ocean wave energy to make a significant...
What are the most effective ways to improve the engineering curriculum? Improvements should result in increased student retention, undergraduates who are more industry-ready and graduates who are better prepared to be leaders. Current research suggests that the best predictor of persistence is a person’s self-efficacy. The focus of this thesis...
With advancements in CMOS technology, high speed analog circuits that were
traditionally implemented with discrete circuit components can now be made monolithically.
Antialiasing filters for video signals as well as signal conditioning filters in high
speed communication channels are examples of applications where high frequency integrated
circuits are now feasible....
A novel switched-R-MOSFET-C input branch is proposed for low-voltage and high-linearity applications. The tunability is achieved by varying the clock duty cycle using an automatic tuning circuit. This tuning method does not involve a change in gate voltage, and is therefore particularly suitable for low-voltage applications. The advantages of the...
Traditionally linear actuator applications are addressed by the use of hydraulic systems. The high maintenance cost and poor reliability will always be the most critical problem in the real applications. Benefited from both the high mechanical advantage of the roll screw and the simple structure of the switched reluctance motor,...
This thesis presents algorithms and tools for the automated design of RF LC CMOS voltage controlled oscillators (VCOs) with low phase noise given a set of specifications. The electromagnetic solver, ASITIC, combined with the circuit simulator, SpectreRF, allows optimization of the VCO circuit parameters and inductor layout. This approach gives...
Amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) constitute the central theme of this thesis. Within this theme, three primary areas of focus are pursued.
The first focus is the realization of a transparent three-stage ring oscillator with buffered output and an output frequency in the megahertz range. This leads to...
A new comprehensive wide-band compact modeling methodology for single-ended spiral inductors and differential spiral inductors is presented. The new modeling methodology creates an equivalent circuit model consisting of frequency-independent circuit elements for use in circuit simulators. A fast automated extraction procedure is developed for determining the circuit element values from...
Low noise oscillators are universally needed in digital systems for clock generation and synchronization, and in radio-frequency communication front-ends for frequency up- and down-conversion. Noise in oscillators results in timing jitter, and limits the clock frequency of digital systems. In radio-frequency communication systems, phase noise in oscillators lowers the signal-to-noise...
This thesis presents the development of a supervisory controller for a pre-commercial
Brushless Doubly-Fed Machine (BDFM) drive system. In addition,
characterizations of new diecast rotors for the BDFM are presented. Using the
characterization results from the new rotors, a control scheme was developed to allow a
BDFM to be packaged...
Electricity is the name given to an invisible agent known to us only by its attendant phenomena and by various manifestations called electrical. These manifestations, at first obscure and even mysterious, are now well understood. Indeed its great importance to mankind can only be realized when we remember that it...
Industry today is pushing personal portable handheld communication de- vices, from cellular telephones to personal navigation systems, and society is embracing the push. The goal is to make compact multi-functional handheld products that can transfer information to those around us through high bandwidth mobile communications. These modules rely heavily on...
In an effort to fill an existing need two small electric service
vehicles were designed, constructed, and tested. The first
acted as a feasibility study and the second as a design prototype.
The vehicles had low cost and the capability of being fabricated by
their users as two main design...
The loads on the electrical systems of automobiles are projected
to increase significantly in the near future. This will result in a
requirement for improved efficiency over the present-day car
alternators. An alternative scheme proposed at Oregon State
University employs a Brushless Doubly-Fed Machine (BDFM) as an
alternator.
This thesis...
Driven by the need for high energy-density power sources, demand has
stimulated the development of small-scale engines. A small-scale engine
with a fuel supply could replace batteries and utilize higher energy-density
liquid hydrocarbon fuels; such an advance could deliver a new age of
portable devices. Currently, operable small-scale engines exist;...
The designing of electrical machinery is fully
as essential to the thorough understanding of power
equipment and apparatus, as is the taking of a laboratory
testing course. One learns the relationship
of the different parts, the methods of computing
their dimensions, and the predetermination of outputs,
efficiencies, etc. and thus...
A variable gain, high linearity, low power baseband filter for WLAN applications is implemented in a 1.5 V 3 V 0.15 μm CMOS process. This fourth-order low-pass filter, which is introduced in the transmit channel as a reconstruction filter between the D/A converter and the mixer, has a measured cut-off...
The design and implementation of Switched-Current (SI) ladder filters is
described. SI filters require only a standard digital CMOS process and the power
supply voltage requirement is low. SI circuits also can be potentially operated at
higher frequencies than Switched-Capacitor (SC) filters due to the low-impedance
wideband nodes of the...
The design of two 2.4GHz CMOS LC balanced oscillators in the 0.25μm National BiCMOS process for Bluetooth specifications is presented. These oscillators achieve low phase noise with low power consumption. At a frequency offset of 500KHz from the 2.11GHz carrier, the measured phase noise is -101.9dBc/Hz for the NMOS oscillator...
A design style is presented for a self-synchronized,
multiple input change, asynchronous state machine which
processes input changes at a speed limited only by the
required machine behavior and implementation technology.
This state machine will operate at this ultimate speed
because of a new asynchronous delay element with unequal
rising...
The alternators in today's automobiles are of the claw-pole or Lundell
construction, which is a readily manufactured, low-cost derivative of the conventional
rotating dc field synchronous generator. The efficiency of the Lundell system is low due
to a complicated magnetic circuit of predominantly solid steel and a high windage rotor...
The increasing popularity of cellular phones with integrated cameras in the
recent past has led to major improvements in its image quality. However, integration of new features, such as mobile email, video streaming, MP3 etc. tend to put the limitation on image quality as camera phone designers struggle to manage...
Samples of insulating materials used in the construction
of electrical machinery and apparatus are
tested for dielectric strength before such are accepted
for use. This is done by applying to the sample a
high voltage until it is pierced through by the electric
spark. This is a parallel case to...
A 300 hp motor and generator testing facility is being completed at Oregon State University. The testing center is the largest independent testing facility west of the Mississippi River. This regional resource center will incorporate state-of-the-art features that set it apart from other testing facilities. An induction machine with a...
The Brushless Doubly-Fed Machine (BDFM) has recently become an
important research topic in the field of variable-speed AC drives. In
recent studies, the BDFM has shown significant potential for improving the
reliability and performance of AC drive systems, as well as reducing total
system cost. While the BDFM offers several...
With increasing transistor operating frequencies, interconnects and passive devices are becoming performance limiters in integrated circuit (IC) designs. To combat this, the interconnect layers above the active silicon are trending toward low-κ dielectrics and Cu metallization. The use of these new materials has popularized chemical mechanical polishing (CMP) to planarize...
CuGaSe₂/CuInSe₂ tandem junction solar cell is currently being pursued to be a low cost and high efficiency renewable energy source. A reported theoretical efficiency of 33.9% solar cells has been the motivation to fabricate CuGaSe₂ films in a simple and low cost method. Electrodeposition is a potentially suitable method to...
In advanced integrated circuit (IC) processes, the metal fill inserted to meet foundry imposed density requirements degrades the performance of interconnects and passive components which ultimately affects the overall circuit performance. Accounting for this degradation through electromagnetic and equivalent circuit modeling is becoming a critical aspect of IC design. However,...
With energy prices rising and increasing concern about the influence of fossil fuels on climate change, wave energy systems are on the verge of commercial implementation. These first generation wave energy converters utilize either pneumatics or hydraulics to convert the mechanical energy of waves into electricity. For the last several...
The focus of this thesis involves developing general fabrication processes relevant to the manufacture of two new devices for the Microscale technology Energy and Chemical Systems (MECS) program at Oregon State University. The two MECS devices developed, capture dots and transparent thin-film heaters (TTFHs), require unique process development for successful...
Brushless Doubly-Fed Machines have potential benefits in variable speed generation and adjustable speed drive applications by combining a robust machine structure with a reduced power converter rating. While recent work has demonstrated feasibility, steady-state performance has not been optimized. The nature of doubly-fed operation causes rotor currents of varying, relatively...
The Brush less Doubly-Fed Machine (BDFM) has the potential to be a more cost effective replacement for conventional induction or synchronous machine drives. The BDFM has two stator windings: a power winding and a control winding. An electronic power converter of variable voltage and frequency is connected to the control...
An AC/AC converter has been designed and implemented for the purpose of
providing a modular drive system with a Brushless Doubly-Fed Machine (BDFM.) This
converter is to be used in laboratory testing and also as part of a demonstration system in
the field.
All hardware needed to start and run...
The objective of this thesis is to design a high speed digital FIR filter. The inputs of the
system come from a Delta-Sigma modulator. This FIR filter takes 1024 inputs,
multiplies them with their coefficients and adds the results. The main design task is to
take the input data, which...
Hybrid electric vehicles (HEV’s) are a very important part of today’s transportation system as they are bridging the gap between fully electric vehicles and conventional internal combustion vehicles (ICV’s). They have much higher efficiencies and lower emissions than ICV’s, while still having the ability to travel long range and refuel...
As more advanced hybrid electric vehicles begin emerging onto the commercial market, design algorithms for their control become increasingly more complicated. One major hurdle for designers is the mitigation and control of the created high frequency harmonics caused from switching the dc voltage into an ac voltage by use of...
Spiral inductors are a key component of mixed-signal and analog integrated circuits (IC's). Such circuits are often fabricated using silicon-based technology, owing to the inherent low-cost and high volume production aspects. However, semiconducting substrate materials such as silicon can have adverse effects on spiral inductor performance due to the lossy...
The purpose of this thesis is to represent and calculate unsymmetrical
secondary faults on a grounded wye-to-delta transformer
bank.
This thesis is specifically concerned with the secondary connections
often encountered in industrial installations. Faults on these
systems have not been adequately investigated.
Three types of faults are considered, namely:
1....
A significantly untapped renewable energy source exists in the world's oceans. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world. Ocean energy extraction is an old concept, and it is currently seeing the benefit of advancing...
A new circuit technique called Folded Source Coupled Logic (FSCL) has been developed
to implement the digital section of mixed-signal IC applications. This FSCL circuit technique
offers the advantage of low overlap current spikes during the switching transitions
of conventional CMOS gates. This overlap current spike has become one of...
The most accurate method for performing analog signal processing in MOS (metal-oxide-semiconductor) integrated circuits is through the use of switched-capacitor circuits. A switched-capacitor circuit operates as a discrete-time signal processor. These circuits have been used in a variety of applications, such as filters, gain stages, voltage-controlled oscillators, and modulators. A...
Variability in circuit performance due to process defects is a major concern in integrated circuit (IC) fabrication. Advanced IC manufacturing processes employ Chemical-Mechanical Polishing (CMP) for planarization of oxide and metal layers. CMP defects result in variations in the oxide and metal topographical profile. To reduce these topographical variations, electrically...
A new, reproducible method of using electromigration to form
metallic nano-conductors is developed using gold and a tin-silver alloy.
Measurements revealed a quantization of the electrical conductance
consistent with the theory of quantum conductance. The theory of
quantum conductance is applied to show that a nano-conductor with a
cross-section of...
This thesis presents new, compact configurations for RF/microwave bandstop and lowpass filters for embedded passive applications. A simple design methodology is presented for designing the folded-transmission line filters on a microstrip platform. Unlike the conventional stub-loaded filter designs, the proposed folded-line filters will have practical dimensions for a wide range...
Mobile and telecommunication industry has experienced tremendous growth in the recent past. Miniaturization and increased functionality have become necessary for all passive components in the system. Bandpass filters are critical passive components in any communication system and the existing designs in the crucial 1-10 GHz bandwidth suffer many drawbacks. For...
The role of A-site non-stoichiometry was investigated in lead-free piezoelectric ceramics based on compositions in the 1-x(Bi₀.₅Na₀.₅TiO₃)-xBaTiO₃ system near the morphotropic phase boundary where x = 0.055, 0.06 and 0.07. The samples were prepared by a conventional solid state mixed oxide route with the A- site stoichiometry modified to incorporate...
Wave energy conversion devices are a rapidly growing interest worldwide for the potential to harness a sustainable and renewable energy source. Due to the oscillatory nature of ocean waves, the power generated from a permanent magnet linear generator (PMLG) for ocean wave energy conversion is pulsed. Focusing on direct drive...
The world’s energy consumption is growing at an alarming rate and the need for renewable energy is apparent now more than ever. Estimates have shown that optimization of the extraction of energy from the ocean could significantly aid the world’s quest for sustainable and affordable energy services for all. From...
Due to advances in high-density low-cost VLSI and communication technology,
digital filtering and signal processing are being widely used for real-time signal processing
applications. Given the filter specification, choosing the best filter structure for a given
application is not a trivial task. The choice of a particular filter structure depends...
The advent of superior power semiconductor devices and converter topologies
has renewed interest in ac drive systems. Although considerable research efforts have
gone into improving power electronic converter devices and topologies, very little has
been reported on the overall performance optimization of induction machine drive
systems. The report of the...
A relatively new development in the electric machines field has been the written-pole technology, of which the latest product is the large single-phase electric motor, the single phase Written-Pole Motor (WPM). The WPM is a synchronous, permanent-magnet single-phase motor having a weak rotor cage for start-up which in addition exhibits...
Electromagnetic engines, or motors, are machines in which the motive power is derived from electric currents by means of their electromagnetic action. The following design is for a 1½ K.W. bi-polar motor.
The electric motor has for an number of
years occupied an important position in the operation
of wood-working machinery, of moderate capacity, for
example the planing mills, sash and door factories
and many of the other similar wood working shops.
However its adoption in the more trying field of saw...
The marked movement of utilizing Oregon's water power
in the service of generating electric current, has been promoted
by the economics in transmission of electricity to distances
both great and small; by the harnessing of industrial
implements to electric power; and by the advancement and extension
of interurban railways.
It...
Basic operation, as well as successful development, of the Brush less Doubly-fed Machine (BDFM) has been documented, and research has turned from proof of concept and early development to the more practical direction of increased manufacturability to prove industrial viability. Previous research centered on using standard induction motor stators along...
Brushless Doubly Fed Machines (BDFM) have potential advantages in variable
speed generation and adjustable speed drive applications. The most significant of these
advantages is a reduction in the power electronic converter rating, and therefore a
reduction in overall system cost. Presently, efforts are being directed at optimizing the
design of...
Ocean wave energy is a new and developing field of renewable energy with great potential. The energy contained in one meter of an average wave off the coast of Newport Oregon could supply dozens of homes with electricity. However, ocean waves are usually quite irregular which leads to large bursts...
The Brushless Doubly Fed Machine (BDFM) is receiving attention as a candidate for use in adjustable speed drives (ASDs) and variable speed generators (VSGs). With a large percentage of a drive or generator system's cost due to power electronics content, considerable research has been conducted to find drives in which...
With an increasing number of wireless applications at microwave frequencies, the frequency spectrum is becoming quite crowded. Due to this congestion, the current state of technology is leading towards upper microwave and millimeter wave spectra as they also offer other distinct advantages such as larger bandwidth and smaller component footprint....
A new structure for the implementation of bit/serial adaptive IIR filter is
presented. The bit level system consists of gated full adders for the arithmetic
unit and data latches for the data path. This approach allows recursive
operation of the IIR filter to be implemented without any global
interconnections, minimal...
Low-distortion architecture is widely used in wideband discrete-time switched-capacitor delta-sigma ADC design. However, it suffers from the power-hungry active adder and critical timing for quantization and dynamic element matching (DEM). To solve this problem, this dissertation presents a delta-sigma modulator architecture with shifted loop delays. In this project, shifted loop...