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...
Permanent magnet synchronous machines (PMSMs) are widely used in electric vehicles and hybrid electric vehicles to propel the wheels. Various control strategies have been developed for PMSM drive systems to achieve both high efficiency and safe operation. In a PMSM drive system, generally the high voltage battery and the power...
Medical imaging technologies play a vital role in early diagnosis of disease by providing internal images of the human body to medical professionals. Computed Tomography (CT) is currently the most commonly used medical imaging technology because it is easy to use, detectors and scanners are constantly improving, and more importantly,...
Recent blackout events consistently show that a variety of mechanisms are involved in cascading outages. These cascading mechanisms are irregularly modeled and validated within the existing literature and industry practices. Understanding the relative significance of these different mechanisms is important for choosing which one(s) needs to be modeled for specific...
The reliability and survivability of a wave energy converter (WEC) is highly dependent on the variability and non-linearity of the ocean itself. Ocean variability occurs on many time scales. Climate variability occurs decade-to-decade, and year-to-year in the number and intensity of winter storms. Seasonal variation of wave height and period...
With the ever-increasing demand and competition for global energy resources among nations, it is essential to explore and tap into various energy sources to reduce dependency on global markets. Renewable energy sources offer a significant opportunity to create localized and stable energy supplies. Ocean wave energy can be a promising...
This research introduces an energy storage system to deliver microgrid frequency response. A doubly-fed induction generator (DFIG) and a squirrel cage induction machine (SCIM) are coupled together as a motor/generator set to deliver an immediate inertial response to a change of frequency, and an inverter and supercapacitors deliver short term...
This thesis presents both an analysis and simulations of a passively controlled variable-speed generator system, which can be applied for renewable energy sources such as wind turbines. Parallel connected passive/external resistors and inductors are connected to the slip rings of a wound rotor induction machine to provide an acceptable speed...
Variable electrical generation (VG) sources such as wind farms are an increasing percentage of total electrical generation in the Bonneville Power Administration (BPA) balancing area and are starting to impact the ability of the regional balancing authority to control the electric grid. Wind farms are not dispatchable and challenge historical...
Over the last decade, wind penetration in the Pacific Northwest has increased rapidly. The variable nature of this massive new resource has increased stress on the hydropower resource to the point where system limits are currently being reached. In order to cultivate continued growth of the wind energy industry both...
The performance of the power take-off (PTO) system for a wave energy converter (WEC) depends largely on its control algorithm. This paper presents an adaptive damping control algorithm that improves power capture across a range of sea states. Validation for the numerical model was performed using data from two sources;...
The number of wind turbines and wind farms in the Pacific Northwest has increased dramatically in the past six years, which represents a significant amount of electrical generation capacity connected to the public electric grid. However, the variable nature of wind sometimes introduces excessive power, or conversely shortages, in power...
This work presents a residential load simulation framework that allows the user to test the effectiveness of peak reduction, peak shifting, and valley filling load management strategies on a representative residential load prior to physical smart sensor and load control deployment. The simulation methodology uses household occupancy, appliance time-of-use, and...
With the recent interest in increasing the penetration of renewable energy sources onto the power grid, there has been an unprecedented rapid deployment of wind generation, especially in the US Pacific Northwest. While wind farm developers have continued to expand their operations, power system operators are left to deal with...
Continual growth of the world's energy consumption and the demand for long-term clean renewable energy resources has led to the development of ocean-based wave energy technologies. Emerging technologies are advancing potential solutions to the complex problem of energy generation in the harsh and corrosive ocean environment. To develop these technologies,...
As more wind farms are connected to the grid, the variable nature of wind energy begins to influence grid stability. Energy storage could help smooth the variable nature of wind energy. Laboratory demonstration and exploration of the interaction between different energy storage devices and wind energy could help improve and...
Researchers at Oregon State University, focusing on the development of ocean wave energy converters, have designed and installed a unique linear test bed to aid in the characterization of these converters. Under the original control scheme, the linear test bed follows a position profile and is limited in its ability...
Modern wind energy is the technology of choice with a short payback period for increasing renewable energy portfolios. Bonneville Power Administration (BPA), a United States power authority in the Pacific Northwest expects to increase their wind energy capacity from 2,000 megawatts to 6,000 megawatts within the next five years. Currently...
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...
As the Tekbots program expands into senior and graduate level classes at Oregon State University, so does the need arise for more complex learning platforms. These complex hardware platforms cannot be adequately tested in a manufacturing environment as we have done previously. Also, due to their complexity, these platforms require...
This dissertation studies the coupled fluid-structure interaction (FSI) of a wave energy converter (WEC) and evaluates the design of a WEC mooring system. The research is conducted in support of conceptual development, field test and performance evaluation of WECs as part of the mission of the Northwest National Marine Renewable...
Recently, there has been peaked interest in developing high energy producing and optimized power take-off topologies for Wave Energy Converters (WEC). As large as the potential of the oceans may seem, harnessing that energy and effectively converting it to electricity in significant amounts is a challenge. Currently, there are no...
Recent opportunities for new hydropower generation in the United States have often been in non-powered dams and run-of-river type flows occurring in low-impact natural areas and unregulated conduits. At the same time, a changing water resource paradigm is challenging some existing generation in drought stricken areas where supply reservoirs behind...
Renewable energy, particularly wind power, has increased dramatically over the past two decades. In the Pacific Northwest, the power system has accommodated a large amount of new wind power. The variability of wind power has introduced many challenges, requiring additional reserve generation to be available to maintain system stability. The...
Ocean wave energy converter technology continues to advance and new developers continue to emerge, leading to the need for a general design, modeling, and testing methodology. This work presents a development of the process of taking a wave energy converter from a concept to the prototype stage. A two body...
Over the last 20 years, there has been rapid growth in the amount of installed wind power in the Pacific Northwest, specifically in the Columbia River Gorge. The variable and non-dispatchable nature of this resource requires that it be balanced in some form by other sources on the grid. In...
As the growth of renewable energy sources, such as wind, solar, and ocean wave, increases, their impact on the electrical grid has been rapidly escalating. Although renewable resources have been able to offset some traditional generation, they have also brought a need for increasing reserve capacity due to their non-dispatchable,...
This thesis describes compensation techniques for cascaded delta-sigma A/D
converters (ADCs) and high-performance switched-capacitor (SC) circuits. Various
correlated-double-sampling (CDS) techniques are presented to reduce the effects of the
nonidealities, such as clock feedthrough, charge injection, opamp input-referred noise and
offset, and finite opamp gain, in SC circuits. A CDS technique...
The 1989 Exxon Valdez oil spill was a major perturbation of nearshore habitats of Prince William Sound, a wintering area for harlequin ducks (Histrionicus histrionicus). This research was designed to evaluate harlequin duck population recovery from the oil spill from 1995 to 1998, using a demographic approach to assess both...
The importance of spectral efficiency in mobile communications often requires the use of non-constant-envelop linear digital modulation schemes. These modulation techniques carry signal information in both magnitude and phase, thus they must be linearly amplified to avoid nonlinear signal distortion which is not correctable in a typical receiver. A second...
Over the last decade the increase in penetration of wind power and its variable nature has begun to add considerable stress to and threatened the stability of the nation's grid. In order to continue growth wind farms will need to have the ability to participate in the same grid frequency...
Ocean wave energy shows great potential as a developing form of renewable energy. However, challenges arise in maturing this technology to achieve cost-effective energy conversion. Development and testing of wave energy converters can be problematic due to the harsh environment in which they are operated. To promote development of this...
The organic Rankine cycle (ORC) is a versatile approach in the utilization of waste heat in the production of electricity, clean drinking water, and cooling. The efficiency of these cycles must be maximized to make them economical. Parameters for the optimization of ORCs such as evaporator and condenser temperature have...
With the increasing effort to identify alternative methods of energy generation, extraction of ocean energy has gathered a large interest. Research and industry have begun considering wave energy as the next new alternative energy. The unique challenges of ocean energy requires a wave energy converter to be both robust and...
This research work focuses on the mechanism of 1/f noise in GaAs
resistors on semi-insulating substrates and 1/f noise due to temperature
fluctuations in heat conduction in resistors, diodes, and bipolar transistors. The
goal of this research is to generate accurate models to explain physical origin of 1/f
noise in...
Stranded natural gas and biogas comprise a vast energy resource that is mostly wasted via flaring. This represents an opportunity to investigate novel ways to harness this resource. Nonthermal plasmas consist of excited electrons, ions and neutral atoms/molecules that have the ability to disrupt chemical bonds at ambient temperatures and...
The primary objective of a grid is to maintain a balance between generation and load. If these quantities are not in balance with each other, severe damages such as voltage fluctuations, low power quality, power outages or even cascaded blackouts may occur. Hence one of the primary factors that holds...
The objective of the work presented herein is the development of the extended Kalman filter for nonlinear system modeling. A standard Kalman filter is a well-known filter for estimating the state of a system, assuming the system is linear and it has a Gaussian distribution in its noise. In reality,...