|
SEMINAR ARCHIVE
|
|
DESIGN OF A CONCEPTUAL FRAMEWORK FOR THE VEHICLE-TO-GRID (V2G) IMPLEMENTATION
|
|
Presented by
Christophe
Guille
on 04/28/2008
|
|
Monday, April 28, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The major increases in oil prices and the rising environmental concerns are key drivers in the growing popularity of electric and plug-in hybrid vehicles. Car manufacturers understand this trend quite well and are developing new models, e.g., the Chevrolet Volt to be released next year. For the 90% of Americans who use their car to go to work every day, the average daily commute distance is 28 miles and the average daily time that cars remain parked is 22 hours. A salient feature that these vehicles have in common is the batteries, which provide good storage capacity that can be effectively integrated into the grid. We focus on the design of a conceptual framework needs to integrate the electric vehicles into the grid – the so-called V2G concept. The basic premise we use is to treat the battery vehicles as distributed energy resources that can act both as supply and demand resources. We assess the deployment of an aggregation of battery vehicles for the provision of frequency regulation – requiring very fast response times – and peak shaving. We also investigate the impacts of the aggregated battery vehicle-charging load on the low load generation schedules and on regulation requirements. The assessment of these impacts takes into consideration the explicit representation of uncertainty and the importance of the state of charge as a key variable in the use of the batteries for the supply and demand roles. For the framework completeness, we also explore the role of the energy services provider in the V2G integration.
|
|
<<click here to download presentation>>
|
|
INCORPORATION OF WIND INTERMITTENCY IN PRODUCTION COSTING
|
|
Presented by
Nicolas
Maisonneuve
on 04/28/2008
|
|
Monday, April 28, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The rapid increase of wind power capacity over the past ten years has benefited tremendously from the technology developments that resulted in significantly reducing the capital investment costs. In addition, with increasing concern about climate change, several countries have adopted policies that foster the use of renewable energy sources so as to reduce CO 2 emissions. Several jurisdictions around the world have specified ambitious targets of the fraction of capacity to come from renewable resources, thereby further stimulating the investment in wind. As a result, wind is the fastest growing source of new capacity for electricity. As the fraction of wind resources becomes larger, the solution of some of the challenging issues in the integration of these resources becomes more pressing. One key issue is the wide variability and difficulty in predictability of wind energy. The intermittent nature of wind and the attendant lack of dispatchability present major difficulties to system operators. In order to operate the system securely, operators must take steps that result in additional operating costs. Such costs have been quantified and analyzed in a number of wind integration studies indicating that these costs become pronounced as the penetration of wind energy approaches the 20% level of the total installed capacity of a system. We are focusing our analysis on developing an improved understanding of the nature of these costs by investigating the impacts of wind integration in a production costing framework. Specifically, we are investigating the modelling of the intermittency impacts and the manner in which they affect the unit commitment schedules. The objective is to construct a practical procedure to explicitly represent the uncertainty in wind regimes in areas with wind farms.
|
|
|
|
DISTRIBUTION AUTOMATED SYSTEM
|
|
Presented by
Guest
Speaker
on 04/21/2008
|
|
Monday, April 21, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: He will give you a short talk about distribution automated system in KEPCO and what KEPCO is planning for the future technology in the electric power industry
|
|
|
|
MODELING THE MAGNETIC FIELD GENERATED BY CORRODING METALS
|
|
Presented by
Melanie
Shelton
on 04/14/2008
|
|
Monday, April 14, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Damage caused by steel reinforcement corrosion plagues the nation’s civil infrastructure. Corrosion damage causes an estimated 6 to 10 billion dollars of damage per year to the US bridge decks alone. There is no reliable non-destructive testing method to detect either the presence of corrosion or the rate at which corrosion occurs. Existing methods, such as visual inspection and half-cell potential measurements, are unable to fully characterize damage. The goal of this project is to develop a new sensing technique based on magnetic field measurements that will accurately measure both the state and the rate of corrosion in reinforcing steel.
The project, which is a joint undertaking with the Civil and Environmental Engineering Department, seeks to employ giant magneto-resistive (GMR) sensors. These sensors will measure the small magnetic field generated by the electric currents set up during the corrosion process. However, to extract the magnetic field information from the background noise, a model is necessary to determine the defining characteristics of the corrosion magnetic field. We use three models to simulate the corrosion magnetic field. Each model generates a random current distribution and calculates the magnetic field. This talk presents the three models and discusses the nature of our analysis using simulation data.
|
|
|
|
Model-Order Reduction of Magnetic Equivalent Circuits
|
|
Presented by
Ali
Davoudi
on 04/14/2008
|
|
Monday, April 14, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Physics-based modeling of magnetic devices is highly desirable for representing their dynamic behavior with good fidelity. Rather than use the conventional finite element-based models, which are not only hard to formulate, but also are oversimplified and computationally intensive, we introduce a magnetic equivalent circuit-based representation that explicitly takes into account geometrical and material information and models eddy current effects. The representation of eddy currents significantly increases the model order and the computational burden. The consideration of system nonlinearities due to saturation and relative motion further taxes the computational burden. We reduce the computing times and complexity through the application of order-reduction techniques to identify the essential system dynamics in the desired bandwidth. The simulation results using the reduced-order model are compared against those obtained using the full-order model.
|
|
|
|
A COMPARISON OF NODAL AND MESH-BASED MAGNETIC EQUIVALENT CIRCUIT MODELS
|
|
Presented by
Guest
Speaker
on 04/07/2008
|
|
Monday, April 7, 2008, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: The magnetic equivalent circuit technique is a powerful analysis and design tool that combines relative accuracy with moderate computational effort. In this research, a nodal-based MEC formulation and a mesh-based MEC formulation of a magnetic system are compared. The Newton-Raphson algorithm is used to solve the algebraic system, and to draw conclusions about the computational efficiency of the two formulations under linear and nonlinear operation. It is shown that when magnetic saturation is represented, a mesh formulation can yield a model that is much more efficient numerically. Specifically, the number of iterations needed for the Newton-Raphson algorithm to converge for the mesh-based model is an order of magnitude lower than that of the nodal-based model. The difference in the number of iterations is largely due to the condition number of the Jacobian matrix, which is much smaller in the mesh formulation. Interestingly, it is also observed that in the case of the nodal formulation, an exact evaluation of the Jacobian leads to a highly ill-conditioned system.
|
|
|
|
AN EVALUATION OF THE IMPACTS OF PLUG-IN HYBRID ELECTRIC VEHICLES ON POWER SYSTEM DISTURBANCE RESPONSE AND ECONOMICS
|
|
Presented by
Steven
Judd
in Spring 2008
|
|
Monday, March 31, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: As energy prices increase, the search for alternative modes of transportation intensifies. One possible solution is the transformation of hybrid vehicles into larger capacity plug-in hybrid electric vehicles (PHEVs). This transformation represents a promising and innovative advancement in technology. PHEVs provide a completely means to store electricity in the power grid. With the larger battery storage, the PHEVs have the ability to provide support to the power grid needed in emergency situations. This presentation explores the benefits of using a heavy penetration of PHEVs to act as support to the grid during disturbances and also assesses the costs incurred in their provision of control capability for security.
|
|
|
|
LOAD MODELING FOR RESOURCE PLANNING IN THE COMPETITIVE ENVIRONMENT
|
|
Presented by
Anupama
Kowli
in Spring 2008
|
|
Monday, March 31, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Load demand is a key driver in power system operations and planning decisions. Demand is met with supply- and demand-side resources. We construct a probabilistic model of the load useable in investigating the impacts of investments in demand- and supply-side resources on a consistent basis, with the impacts of competitive electricity markets taken into account. The model is required to be able to interface with models that incorporate the impacts of transmission congestion and of the electricity market outcomes. In light of these requirements, we incorporate a load classification scheme that easily allows the interface with models that use snapshot representations of the power system with transmission considerations and market clearing included. The load classes effectively capture the critical peak loads, with which congestion and DSM activities are predominant. We present numerical results illustrating the characteristics of the load model.
|
|
|
|
MIDWEST ISO MARKET AND RELIABILITY INITIATIVES
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, March 24, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: This presentation will provide an overview of the new developments at the Midwest ISO. The focus is on some of the recent developments in the electricity markets and the reliability projects of the Midwest ISO. The discussion will cover the ancillary services market launch and its importance, the developments in the electricity markets operated by MISO and a brief overview of the operations of the largest energy management system in the world. In addition, the planning and coordination activities of the Transmission Asset Management group and the progress on the wind forecasting initiative will be discussed.
|
|
<<click here to download presentation>>
|
|
Real-time estimation of power system dynamics
|
|
Presented by
Shanshan
Liu
in Spring 2008
|
|
Monday, March 10, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Many power systems are currently operating under heavily stressed conditions and with rather slim stability and security. There is an acute need to better understand the nature of power system dynamic behavior and to have good knowledge of the dynamic states of the system in order to be prepared for critical situations as they arise. As such, the updating of dynamic system models in real time is a key requirement. The deployment of phasor measurement units (PMUs) enables the direct observation of system oscillations including under system disturbances. We study advanced filtering concepts, such as sequential importance sampling, and apply them to the real-time estimation of power system
dynamics. The simulation results show that more realistic system models
based on frequently updated parameters are obtainable with the PMU data
collected.
|
|
|
|
MEDIUM VOLTAGE MOTOR DIAGNOSTICS
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, February 25, 2008, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: This seminar will present recent work done in the area of diagnostics and condition monitoring of large, medium voltage motors. In addition, the new 4kV motor test laboratory and dynamometer facility at Georgia Tech will be described.
|
|
|
|
2007 SOLAR DECATHLON AN ELECTRICAL ENGINEERING PERSPECTIVE
|
|
Presented by
Trishan
Esram
in Spring 2008
|
|
Monday, February 25, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The 2007 Solar Decathlon took place on the National Mall, in Washington D.C., on October 12–20, 2007. The UIUC team competed with nineteen other teams from colleges/universities from North America and Europe for the most aesthetically appealing and energy-efficient solar-powered house. We discuss the design of the photovoltaic electrical system of the UIUC Solar Decathlon house and the implementation steps taken. We highlight the electrical and safety standards and codes, as they apply to photovoltaic electrical systems. We focus on the electrical performance, along with the overall performance, of the house during the decathlon.
|
|
<<click here to download presentation>>
|
|
The Development of Scalable and Deployable Military Microgrids
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, February 18, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The U.S. Army and the Department of Defense have launched an investigation of the feasibility of developing an "intelligent" decision and control architecture for an electric power distribution network. Such a network is designed to allow "plug-and-play" interconnection of a diverse range of distributed generation (DG) technologies, energy storage equipment, and the critical loads that are served, into a readily scalable and deployable microgrid. The ultimate objective is to deliver the available power at any point in time to the prioritized critical loads. The most significant technical challenges in this microgrid design are the issues of the control architecture, the self-healing/auto-reconfiguring distribution topologies, and the agent-based data communication protocols.
The military microgrid will be used at both the installation level (small community size) and scaled down for deployment to Forward Operating Base (FOB) and Tactical Operations Center (TOC) applications. In addition, the microgrid will serve to rapidly restore power to an existing utility grid that has lost power, due to damage to the main central power plant and/or surrounding regional grid, whether by natural disaster, terrorist attack, or combat objective. Until the damage to the existing equipment is repaired, such capability allows reconstruction personnel to move in with a diverse array of DG assets, including conventional engine-driven generators, advanced DG technologies and renewable energy technologies, and connect them to the de-energized local grid so as to create an "islanded" intelligent microgrid.
|
|
|
|
HIGH-PERFORMANCE ACTIVE TEST AND FORMATION EQUIPMENT FOR BATTERIES
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, February 11, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Bitrode, now in its 51st year, is a global company that engineers and manufactures formation and test equipment for the battery industry. Bitrode equipment is the de facto standard for automotive and industrial lead-acid batteries, and advanced products exist for other chemistries, including lithium-ion cells and ultracapacitors. As storage technologies progress, researchers are requiring ever faster and more precise equipment. The test and formation equipment and circuits for modern batteries must support all possible ranges of energy storage to meet battery manufacturing requirements for pacemakers, satellites, hybrid electric vehicles, conventional starting-lighting-ignition (SLI) batteries, uninterruptible power supplies, and all other areas. Emerging requirements lead to the need for fully-controlled bidirectional power sources
capable of milliwatts to megawatts, with millisecond response times and precise outputs. These unusual requirements, especially the need for bidirectional power supplies with fast dynamics, are driving a new generation of power electronics for the battery industry. In this talk, the current charging technologies and practices are described. Emerging requirements for advanced power electronics designs will be outlined. State-of-the-art designs, tradeoffs, and new approaches will be reviewed. The transition to highly efficient switching systems with multi-quadrant output performance is outlined.
|
|
|
|
Residential Solar Power In The Midwest
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, February 4, 2008, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: Solar photovoltaic (PV) electric power is currently the subject of substantial research, investment, and debate. Although sunny states like California, New Mexico, and Arizona are at the center of much discussion, this talk addresses the use of residential solar power in the Midwest. The presentation will include background on the basics of PV power systems, including a walk-through on the specification, design, and performance analysis of case study. Since cost is the largest obstacle to widespread use of PV power systems, the presentation will also cover the cost drivers and levelized cost of energy, with a look ahead to future expectations for performance. Finally, the issues surrounding interaction with utilities, such as metering and real-time pricing, will be discussed
|
|
|
|
Power System Data Contouring Using Graphical Processing Units
|
|
Presented by
Zeb
Tate
in Spring 2008
|
|
Monday, January 28, 2008, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: To improve situational awareness in power systems, one useful tool used in control centers is bus (or substation) data contouring. The early methods used CPU processing, leading to long contour rendering times, provided little interactivity with the visualization. To improve interactivity and improve the data rate, contouring methods utilizing graphical processing units (GPUs) show much promise. This presentation focuses on a GPU-based contouring algorithm which can easily outperform state-of-the-art CPU-based contouring algorithms. We discuss sample rendering times for a typical power system display, along with comments on the relative advantages and disadvantages of using the CPU and GPU to perform contouring.
|
|
<<click here to download presentation>>
|
|
ASSESSMENT OF TOTAL TRANSFER CAPABILITY USING IPLAN:
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Tuesday, January 15, 2008, 1:00 – 2:00 p.m., Room 50, Everitt Lab ------------ Abstract: Power transfer capability has been recently highlighted as a key issue in many power systems. Transfer capability is a function of the thermal stability, dynamic stability and voltage stability limits of the interconnected system. This presentation discusses a tool for determining total transfer capability from a static voltage stability viewpoint using IPLAN, which is a high level language used with the PSS/E program. The tool was developed so as to analyze static voltage stability and to determine the total transfer capability between different areas from a static voltage stability viewpoint by tracing stationary behaviors of power systems. A unified power flow controller (UPFC) is applied for enhancing total transfer capability between different areas to address the limitations imposed by the static voltage stability requirements. We present the evaluation of the total transfer capability of the KEPCO power system together with the impacts of enhancing the total transfer capability using the UPFC.
|
|
|
|
REMOTE SENSING CONCEPTS FOR URBAN UTILITY SYSTEMS:
|
|
Presented by
Guest
Speaker
in Spring 2008
|
|
Monday, January 14, 2008, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: USA ERDC-CERL is currently sponsoring a research program to map urban utility system conditions and lay outs in foreign regions of military interest. Special emphasis is given to utility systems in urban regions as much of the utility infrastructure in these areas is underground. The utility mapping algorithms use known, inferred, and remotely sensed utility system information to build estimated system maps. Graph theory is used to map the systems and classify various utility assets in a hierarchical manner (e.g. generating plant, substation, consumer). Utility mapping algorithms will infer connections (vertices) between system nodes using rules based on engineering, local construction practices and materials. Remote sensing systems are also used to identify and detect underground utility system assets, the detection systems include ground penetrating radar, electromagnetic pipe locators, and arrayed systems
|
|
|
|
HYDROGEN FUEL CELL FOR EMERGENCY BACKUP POWER
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, December 3, 2007, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: This presentation will discuss the Plug Power fuel cell systems, the fuel cell installation sites, the deployment strategy, and the research goals of the project; which include the fuel cell operation, availability, and addresses the lifespan of the fuel cell stack and failure modes of the fuel cell components. Since the early 1990’s, the U.S. Army Engineer Research and Development Center – Construction Engineering Research Laboratory (ERDC CERL) has performed numerous fuel cell research projects. ERDC-CERL has experience in siteing over 91 Proton Exchange Membrane (PEM) fuel cells installed at 56 Department of Defense (DoD) installations. ERDC-CERL is providing technical expertise to a collaborative effort fuel cell project between U.S. Army Tank Automotive Research, Development and Engineering Center, National Automotive Center (TARDEC-NAC), the New Mexico Army National Guard, ARINC, and Plug Power Corporation. This project is to deploy twenty Plug Power GenCore 5B 5kW hydrogen fueled fuel cells at New Mexico Army National Guard sites. The fuel cells will provide backup power to critical loads at various National Guard sites located in Santa Fe and Rio Rancho. This project expands critical backup capability and surety, provides environmentally sound energy devices and promotes innovation and high-technology expertise within the National Guard. This project demonstrates the commitment of the federal government and the State of New Mexico to move toward alternate energy storage and power generation.
|
|
|
|
LOAD MODELING FOR LONG TERM PLANNING STUDIES
|
|
Presented by
Anupama
Kowli
in Fall 2007
|
|
Monday, November 26, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Demand forecasting plays an important role in power system planning and operation. The system demand acts as a driver for supply and investment decisions. The purpose of this presentation is to review the concepts of modeling the load (or demand) for long-term studies. We propose a probabilistic load model to describe the uncertainty of the future system load. We consider the load to be a random variable and we take into account the load growth and its seasonal nature. We discuss our plans to use this load model in the analysis of resource investment strategies.
|
|
|
|
Auction Design for the Acquisition of Future Electricity Supply
|
|
Presented by
Matias
Negrete-Pincetic
in Fall 2007
|
|
Monday, November 26, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: We investigate the design of auctions for future electricity supply, used as a basis for the contracts to meet the future needs of a distribution company to fully or partially satisfy the forecasted load. The essential issues in the auction design are the product definition – the way in which the load is categorized and what the basic unitary product is – and the auction format – the way in which the sellers and the buyers are brought together and the method to clear the market. In this talk, we focus on the product definition. We illustrate the importance of the auction design and illustrate with the results of the 2006 Illinois Electricity Auction. We show how the product definition used in such a process defined an uncertain and unnatural product that impacted the final results. In addition, we propose an alternative product definition based on the segmentations of the load into three groups. For each segment, ‘blocks’ of fixed duration and power are defined.
|
|
|
|
ELECTRICITY MARKET SIMULATION AND HYDRO POWER
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, November 12, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: In this seminar, we present the latest advances in electricity market simulation and hydro power modeling at Argonne and introduce a new multi-agent model of generation expansion in electricity markets. The model simulates generation investment decisions of decentralized generating companies (GenCos) interacting in a complex environment. A probabilistic dispatch algorithm calculates prices and profits for new candidate units in different future states of the system. Uncertainties in future load, hydropower conditions, and competitors’ actions are represented in a scenario tree, and decision analysis is used to identify the optimal expansion decision for each individual GenCo. The model is tested with real data from the Korean power system under different assumptions about market design, market concentration, and GenCo’s assumed expectations about their competitors’ investment decisions. The proposed work will help the Korean government and its generating companies implement an integrated resource plan that accounts for the complex and changing environmental, economic, and institutional constraints.
Argonne has also developed several general and customized hydropower system models, which are driven by a combination of economic, financial, and institutional objectives. Models account for physical system attributes and operational limitations that are scripted to meet environmental protection goals. The level of power system granularity in terms of system components and scope are specified by the user. Currently these models are used for pre-scheduling hydropower operations, the hourly scheduling of power contracts, and the economic evaluation of proposed environmental regulations. We discuss the future development of our model such as centralized security constrained unit commitment as well.
|
|
<<click here to download presentation>>
|
|
Battery Management for Maximum Performance in Plug-In Electric and Hybrid Vehicles
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, November 5, 2007, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: Battery energy and power density are limiting factors in the design of electric and hybrid vehicle systems, particularly in the context of wide-range cycling needed for plug-in systems. Many commercial hybrid designs are controlled around specific operating conditions for long battery life. In this paper, battery management aspects for long operating life are discussed. Electrical considerations in valve-regulated lead-acid batteries, nickel-metal-hydride batteries, and lithium-ion batteries are described. Emphasis is provided on charge balancing requirements, state-of-charge operating ranges, and compensation techniques. The role of ultracapacitors for power buffering is addressed briefly. It is shown that certain types of lithium-ion cells offer considerable promise because of their high input-output energy efficiency and possibility of relatively wide operating range. Charge balancing is known to be a vital aspect, and balancing requirements are quantified for sample systems.
|
|
|
|
Data-Driven Power System Analysis
|
|
Presented by
Linda
Monge-Guerrero
in Fall 2007
|
|
Monday, October 29, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: We focus on the application of time-synchronized phasor measurements obtained from phasor measurement units (PMUs) to the dynamical modeling and voltage stability analysis. The aim is to use the PMU data for dynamic modeling based voltage stability studies making use of equivalent dynamic models. We present a method to model a large power system network connected to a load bus by a simplified model consisting of a single generator and a single lossless transmission line. The model parameters are obtained from the least-squares estimation of the PMU data. We discuss plans to study possible applications of the equivalent dynamic models to the small signal voltage stability study.
|
|
|
|
Distributed Intelligent Agents for Distribution Network Restoration
|
|
Presented by
Angel
Aquino
in Fall 2007
|
|
Monday, October 29, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Under normal circumstances, the power system network is operated and coordinated from the control center. The distribution network differs from the transmission network in that it is primarily radial in structure and has many points of connection with normally open switches. The recent advances in technology allow the remote control of the operation of these switches. We study the concept of distributed agents in charge of starting local control actions in the case of a system blackout or any other abnormal situation. The agents coordinate control actions (opening and closing lines) by communicating directly among themselves instead of with the central control center. We present simulation scenarios on power system restoration using the distributed agents approach. We discuss the communication requirements to coordinate the control actions and future work.
|
|
|
|
Calculating Induced Currents in Induction Machines Using Schwarz-Christoffel Mapping
|
|
Presented by
Tim
O'Connell
in Fall 2007
|
|
|
|
<<click here to download presentation>>
|
|
INVESTIGATION OF A PROBABILITY CHARACTERIZATION
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, October 15, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The frequent occurrences of large-scale blackouts in recent years, such as the Northeast blackout in North America on August 14, 2003, draw attention to the vulnerability of power systems. As numerous factors are involved in operating a power system, a thorough understanding of the workings of a blackout is still not clear. At the current stage of research, it is necessary to qualitatively investigate the general principles of blackouts, which can be used to predict and to mitigate power system blackouts. We propose a mechanism of blackouts using the analysis based on the commonly used nonlinear model of power systems and we derive a probability distribution for blackouts from the mechanism of power system blackouts. We discuss numerical results on different power systems that we conducted. These simulation results indicate that the proposed probability distribution of blackouts provides a good description of the behavior of the power system.
|
|
|
|
DAY-AHEAD UNIT COMMITMENT WITH DEMAND RESPONSE IN CAPACITY BASED RESERVES - ANCILLARY SERVICE MARKET AND ENERGY MARKET
|
|
Presented by
Rajesh
Nelli
in Fall 2007
|
|
Monday, October 15, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: We consider the unit commitment problem with the inclusion of the demand response provided by the load-side participants in the electricity markets – the so-called as demand response resources (DRRs). The DRR participants offer to curtail their load and if their bids get accepted, they get paid and, in return, they have to reduce their load for the specified period. We assess the load recovery effect that may occur with a DRR and include it in the day-ahead unit commitment problem formulation. The solution of the unit commitment problem is used to provide valuable insights into the impacts of DRRs in electricity markets with the combined trading of energy and capacity reserves.
|
|
<<click here to download presentation>>
|
|
ON A NECESSARY CONDITION FOR POWER SYSTEM COLLAPSE
|
|
Presented by
Hector
Pulgar
in Fall 2007
|
|
Monday, October 15, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: The purpose of this presentation is to review the concepts involved in establishing a necessary condition for power system collapse. This necessary condition uses complex branch power flows and the so-called static transfer stability limits of branch elements (STSL). The nature of this condition essentially requires that at least one branch element reach its maximum active power flow limit given in terms of STSL before the system collapses. As such, the knowledge of the complex power flow trajectories allows the prediction of the system collapse. We develop a routine to determine the complex power flow trajectories in each branch that reaches its STSL. We determine the point of collapse using an algorithm which maximizes the transfers in the system. We discuss applications to the IEEE test systems of 14 and 57 buses.
|
|
<<click here to download presentation>>
|
|
ON-LINE VOLTAGE AND DYNAMIC SECURITY ASSESSMENTS AND CONTROL: THEORY, NONLINEAR COMPUTATIONS, PRACTICAL INSTALLATIONS AND FUTURE DIRECTIONS
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, October 8, 2007, 4:00 – 5:00 p.m., Room 50, Everitt Lab ------------ Abstract: Certain transmission corridors around the world are being forced to carry more power than they were originally designed to carry. These difficulties, coupled with a steady increase in load demands, have forced electric power systems into being operated with technical difficulties such as degraded reliability, degraded security, and degraded power quality. To a large extent, these changes have contributed to the emergence of the new types of complex behavior observed in many power systems. Such examples include the phenomenon of voltage instability and/or collapse and transient instability. In this talk, a comprehensive package for on-line voltage stability assessments and control of large-scale power systems will be presented. The tool handles the full AC nonlinear modeling of the power system in the base-case conditions and under a contingency list. It takes the general characteristics of power system operating environments into account and includes the effects of control devices. We will also present the TEPCO-BCU tool, an integrated package developed under joint multi-year efforts between Tokyo Electric Power Company, Tokyo, Japan and Bigwood systems, Inc., Ithaca, NY, USA, for fast and yet exact transient stability assessment and control of large-scale power systems for on-line mode or on-line study mode, or off-line planning mode. The algorithmic methods behind TEPCO-BCU include BCU method, Group-based BCU method, BCU classifiers, improved energy function construction, and BCU-guide time domain method. To meet the on-line dynamic security assessment for large power systems such as 14,000-bus power systems, a parallel version of TEPCO-BCU, termed Parallel TEPCO-BCU has been developed. Applications of TEPCO-BCU, Parallel TEPCO-BCU to real-time stability monitoring system will be described
|
|
|
|
PULSE-DENSITY MODULATION FOR RF TRANSMITTER APPLICATIONS
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, October 1, 2007, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract: Conventional wireless transmitters use linear (class-A, AB) power amplifiers to perform amplitude modulation for high-datarate standards such as 802.11a/g/n that require high spectral efficiency. In these applications the power amplifier (PA) typically operates with average efficiency in the range of 5% due to strict linearity requirements. In this work we present a new transmitter architecture that uses pulse-density modulation to perform linear amplitude modulation of a 1.95GHz carrier with a class-D PA implemented in 90nm digital CMOS. Our approach uses deterministic (programmed) pulse density modulation operating at the RF carrier frequency, combined with baseband Sigma-Delta modulation operating at 100MHz. The multi-stage approach shapes quantization noise away from the signal band allowing effective reconstruction of 64QAM OFDM waveforms with minimal digital processing power. The class-D PA achieves a maximum output power of 20dBm and maximum efficiency of 43%, including PA driver power. A current recycling scheme allows the system to operate with 2.5mW digital processing power from a 1.0V supply. Average efficiency for the system is 19.5% for OFDM waveforms with 10.8dB peak-average power ratio
|
|
|
|
POST-CONTINGENCY VOLTAGE AND REACTIVE POWER ESTIMATION AND LARGE ERROR DETECTION
|
|
Presented by
Pablo
Ruiz
in Fall 2007
|
|
Monday, September 24, 2007, 3:00 – 4:00 p.m., Room 50, Everitt Lab ------------ Abstract:
Operational reliability studies require the solution of post-contingency power flows. Fast approximation methods are valuable tools since they reduce the computations in contingency studies. Sensitivities are widely used to approximate real power flows and bus angles annd they provide a good trade-off between accuracy and speed. In contrast, sensitivity-based approximation methods for reactive power and voltage have not been as successful, partially because equipment limits are ignored. In this presentation we discuss the estimation of post-contingency voltages and reactive power generation and flows using sensitivities. Contingencies that lead to large estimation errors are detected in the nodal power mismatches of the estimated state. Representative results are presented using the IEEE 57-bus test system.
|
|
|
|
WIDE AREA PHASOR DATA VISUALIZATION
|
|
Presented by
Zeb
Tate
in Fall 2007
|
|
Charles M. Davis and Joseph E. Tate, Monday, September 24, 2007, 3:00 – 4:00 p.m., Room 50, Everitt Lab ---------------- Abstract:
Phasor measurement units (PMUs) are beginning to be deployed widely in the power system. The PMUs give system controllers the ability to directly measure phase angles. For the time being, PMUs are deployed at only a small percentage of buses. This presents the challenge of how to get useful information from the small number of data points. This paper discusses work that has been done on visualizing the new data provided by PMUs. The presentation introduces the problems associated with visualizing PMU data in a wide area sense and discusses the application of equivalent circuit theory to arrive at equivalent injections. We introduce the difference contours as a means to alert operators to important changes without a cluttered display and apply these ideas to a large example system. We discuss future work on this topic.
|
|
<<click here to download presentation>>
|
|
BEHAVIORAL ANALYSIS OF VARIOUS IGBT STRUCTURES UNDER HARD AND SOFT OVER-CURRENT TURN-OF
|
|
Presented by
Abhishek
Banerjee
in Fall 2007
|
|
Monday, September 17, 2007, 4:00 - 5:00 p.m., Room 50 Everitt Lab --------- Abstract:
The protection of insulated gate bipolar transistors (IGBTs), which are widely used in high-voltage inverters for automotive and various industrial motor-drive applications, from over- and short-circuit current during operation is required for maintaining system reliability. A fault in an electric machine drive causes an IGBT current substantially higher than the rated value – often by an order of magnitude during a short-circuit. This may result in device rupture due to:
• Thermal dissipation: The higher current and the fast thermal time constant may cause the junction temperature of the device to rise in a very short time; or,
• Latching: The intrinsic p-n-p-n thyristor in the IGBT can latch at higher current, resulting first in loss of device gate control and leading to rupture; or,
• Over-voltage: Turn-off of IGBTs at higher currents can cause voltage overshoot due to parasitic inductances and when the overshoot exceeds the breakdown voltage, it may lead to silicon damage.
This project analyzes over-current and short-circuit behavior of 600 V/30 A IGBTs made by International Rectifier (R) and Infineon Technologies (R). A behavioral comparison of the two devices is carried out during hard and soft shut-down following over-current detection. The "desaturation detection" protection scheme, where the collector-emitter voltage is monitored is employed. Sudden unexpected high currents cause the IGBT to leave its saturation stage, thereby forcing the voltage across the device to rise when it should otherwise be low in the on state. The detection of the rise initiates the protection circuitry, lowering the gate voltage to reduce the collector-emitter current, and in some cases, shutting down the device altogether. Shut-down can be regular (hard) or soft, where the timing is controlled by external capacitors and Zener diodes. However, in certain applications, soft shut-down may not occur. The analysis of the response of different IGBT structures to hard and soft turn-off will be presented.
|
|
|
|
COMPONENTS OF COMPETITIVE ELECTRICITY MARKETS
|
|
Presented by
Guest
Speaker
in Fall 2007
|
|
Monday, September 10, 2007, 4:00 ¨C 5:00 p.m., Room 50 Everitt Lab --------- Presented by: Brian Garden and Dane Barhoover, Bibb and Associates, Inc., Lenexa, KS ---------- Abstract: The US Power Market has undergone significant changes in structure and in fuel base over the last 40 years. The dominant utility based structure and utility driven construction has given away to independent power producers with privately owned generation. The significance of coal as a base fuel has waned through the 1990s only to reemerge this decade as a major player along with a resurgence in nuclear activity as well as a heavy reliance on natural gas fueled generation. The discussion of the why/who/where of power generation facilities, the technical basics of these facilities, and major components of the plants is essential as the power generation industry faces a new surge in construction to replace aging megawatts and supply future load growth. Other alternative energy sources such as ethanol and the construction of ethanol production facilities in the mid-west are also on a 5-10 year horizon.
---------- Biography:
**** Brian Garden, PE - serves Bibb as a lead electrical engineer with experience in the design of electrical systems for gas-fueled power plants, ethanol facilities and waste-water treatment plants. His assignments include both office design and field services. Past experience includes serving as field engineer for two combined cycle power plants. Recent engagements include serving as the lead electrical engineer on a simple cycle power plant and on two ethanol facilities. BSEE, Rose-Hulman Institute of Technology, 2001 Professional Engineer - Kansas. ****** Dane Barhoover, EIT - serves Bibb as an electrical engineer with experience in the design of electrical systems for gas-fueled power plants and ethanol facilities. Before joining Bibb, Dane was an electrical engineer for an electric utility, where he improved and implemented standards, designed transmission lines, performed reliability analysis, and served as a field engineer for distribution operations. BSEE, Rose-Hulman Institute of Technology, 2001, BSEE, University of Illinois at Urbana-Champaign, 2003, Professional Engineer ¨C Kansas
|
|
|
|
Assessment of the 2006 Illinois Electricity Auction
|
|
Presented by
Matias
Negrete-Pincetic
in Spring 2007
|
|
The restructured electricity industry aims to fully harness the benefits of competitive forces through the introduction of electricity markets. Both sellers and buyers of electricity face inherent uncertainties due to the nature of electricity and electricity markets. The principal sources of uncertainty include the volatility of the electricity prices, the dependence of the demands on weather conditions and the availability of the generating units. A key thrust in the effective management of these uncertainties is the implementation of forward contracts for capacity. In this talk, we present a review and a critical analysis of the design of, and the results obtained in, the reverse capacity auction performed in Illinois in September 2006 for the two major distribution companies, ComEd and Ameren. We discuss the basic aspects of reverse auctions, the definition of the products in electricity and the key outcomes that were obtained.
|
|
|
|
ASSESSMENT OF THE 2006 ILLINOIS ELECTRICITY AUCTION
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
Monday, April 30, 2007, 4:00 ¨C 5:00 p.m., Room 50 Everitt Lab -------- Presented by: Matias Negrete-Pincetic, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign -------- Abstract: The restructured electricity industry aims to fully harness the benefits of competitive forces through the introduction of electricity markets. Both sellers and buyers of electricity face inherent uncertainties due to the nature of electricity and electricity markets. The principal sources of uncertainty include the volatility of the electricity prices, the dependence of the demands on weather conditions and the availability of the generating units. A key thrust in the effective management of these uncertainties is the implementation of forward contracts for capacity. In this talk, we present a review and a critical analysis of the design of, and the results obtained in, the reverse capacity auction performed in Illinois in September 2006 for the two major distribution companies, ComEd and Ameren. We discuss the basic aspects of reverse auctions, the definition of the products in electricity and the key outcomes that were obtained.
|
|
|
|
The Schwarz-Christoffel Method Applied to Electric Machine Slot Shape Optimization
|
|
Presented by
Tim
O'Connell
in Spring 2007
|
|
Schwarz-Christoffel (SC) maps may be combined with analytical schemes to solve complex boundary value problems in electromagnetics. This fact stimulates an examination of the application of SC maps to construct a viable electric machine design tool that is an alternative to purely numerical methods such as finite element techniques. This seminar discusses the successful implementation of the SC method in a Monte Carlo electric machine slot shape search algorithm. The objective is to maximize the average steady-state machine torque under constrained flux density. In the optimization, fixed slot current density is enforced and the slot shape is varied over a twelve-variable search space. Rotor motion is simulated by changing the position of the machine air gap polygon¡¯s rotor vertices while maintaining both a simply-connected polygon and a shift of ninety electrical degrees between the stator and rotor q-axis currents. Rotor force is calculated by integrating Maxwell's stress tensor along a closed path enclosing the rotor. The Monte Carlo search of 11,050 designs is described and a minimum cost horizon curve is obtained from the data. In addition, an historical context for the SC approach, a brief comparison to both finite element and boundary element methods, and future research objectives are discussed.
|
|
<<click here to download presentation>>
|
|
HIGHLY-RELIABLE AND FLEXIBLE MICROGRID WITH MULTIPLE-INPUT DC-DC CONVERTERS
|
|
Presented by
Alexis
Kwasinski
in Spring 2007
|
|
Monday, April 16,2007, 4:00-5:00 p.m., Room 50 Everitt Lab -----------------Abstract: The presentation analyzes a microgrid-based alternative to the traditional solutions in applications requiring a highly-reliable and low-cost power supply, such as telecommunications power plants. To achieve ultra-high availability, the proposed microgrid power plant combines the output of different types of microsources into a main dc bus using multiple-input dc-dc converters. The presentation discusses a converter topology suitable for the proposed microgrid-based architecture, the system characteristics and the key challenges. The microgrid-based telecom plant technology may be extended to other areas. We describe some of these other applications, such as power provision following natural disasters, power for automobiles, and electric distribution for industries or residential neighborhoods.
|
|
|
|
OVERVIEW OF FERC ORDER NO. 890
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
Monday, April 9, 2007, 4:00-5:00 p.m., Room 50 Everitt Lab -------- Presented by: Neal Balu, Director, Transmission Policy, Wisconsin Public Service Corporation, Green Bay, Wisconsin ---------Abstract: The Federal Regulatory Energy Commission (FERC) issued on February 16, 2007 Order No. 890 (Docket Nos. RM05-17-000 and RM05-25-000) titled ¡°Preventing Undue Discrimination and Preference in Transmission Service¡±. Order No. 890 is a final rule reforming the Open Access Transmission Tariff (OATT) rules implemented in Order Nos. 888 and 889 almost 10 years ago. While Order 890 retained the core elements of Order No. 888 such as native load protection, federal/state jurisdictional lines and functional unbundling, the reforms of the new Order became necessary to address certain shortcomings in Orders No. 888 and No. 889. In particular, specific rules are promulgated on dealing with the opportunities for undue discrimination, the lack of consistency in the determination of Available Transfer Capability (ATC), the lack of transparency in transmission planning , the discriminatory pricing of imbalances and the concerns regarding redispatch/conditional firm service. This presentation will discuss the following key provisions of Order No. 890: * application and scope of the Order; * consistency and transparency of ATC calculations; * coordinated, open and transparent planning including the nine planning principles; * transmission pricing reforms; * improvements in the provision of point-to-point service; * reform of roll-over rights; * designation of network resources; and strengthened enforcement.
|
|
|
|
CONTROL OF A DOUBLY-FED INDUCTION WIND GENERATOR UNDER UNBALANCED GRID VOLTAGE CONDITIONS
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
Presented by: Dr. Ted K.A. Brekken, Electrical Engineering & Computer Science, Oregon State University, Corvallis, OR. ----Location: TELEseminar, Room 50, Everitt Lab, 3:00 p.m. CST ----Participation: The connection will be available approximately 10 minutes prior to the start of the seminar. The audio connection is available toll-free at (800) 392-1565 or locally at the University of Illinois, (217) 265-9888. NetMeeting connection 128.174.112.5. ----Abstract: Wind energy is often installed in rural, remote areas characterized by weak, unbalanced power transmission grids. In induction wind generators, unbalanced three-phase stator voltages cause a number of problems, such as over-current, unbalanced currents, reactive power pulsations, and stress on the mechanical components from torque pulsations. Therefore, beyond a certain amount of unbalance, induction wind generators are switched out of the network. This can further weaken the grid. In doubly-fed induction generators, control of the rotor currents allows for adjustable speed operation and reactive power control. A doubly-fed induction generator control strategy is presented that enhances the standard speed and reactive power control with controllers that can compensate for the problems caused by an unbalanced grid by balancing the stator currents and eliminating torque and reactive power pulsations.
|
|
|
|
THEORY AND ANALYSIS OF SERIES-CONNECTED INDUCTION MACHINES
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
Monday, March 26, 2007, 4:00 - 5:00 p.m., Room 50 Everitt Lab ------ Presented by: Dr. Said Ahmed-Zaid, Department of Electrical and Computer Engineering, Boise State University, Boise, Idaho ------Abstract: A series-connected induction machine is a conventional three-phase wound-rotor induction machine with its stator and rotor coils connected in series but with reverse phase sequences. This machine is analyzed using both reference frame theory and space phasors. All machine inductances appear constant, except for the saturation effects, in a special reference frame that rotates at half the mechanical shaft speed. There are two possible regimes of operation for this machine. With the help of a prime-mover, the machine can operate as a high-reluctance synchronous machine with a shaft speed equal to twice the mechanical synchronous speed. Operation as a motor may not be possible due to lack of damping torque if the machine does not have an additional rotor squirrel cage. If the machine is connected to a three-phase supply, it runs in an asynchronous mode of operation similar to a conventional induction machine except for additional speed and torque vibrations. An equivalent circuit is constructed to explain the operation of this machine in the asynchronous regime. Steady-state torque and power curves are compared for a conventional wound-rotor induction machine and the same machine reconfigured as a series-connected induction machine. The higher torque and power capability of the series-connected machine has potential applications to low-to-medium power wind energy systems.
|
|
|
|
GEOMETRIC AND GAME THEORETIC CONTROL OF ENERGY ASSETS IN SMALL¨CSCALE POWER SYSTEMS
|
|
Presented by
Wayne
Weaver
in Spring 2007
|
|
4:00-5:00 p.m., Room 50 Everitt Lab ---- Abstract: Power electronics are extensively deployed throughout the power system, including in many loads and renewable energy resources. Such widespread deployment represents both a curse and a blessing to the power system design engineer. The curse arises because power electronic loads can regulate energy intake so tightly that negative impedance instabilities and voltage collapse can result. The blessing is due to the ability to control the terminal characteristics at both load and source so as to have desirable attributes and manage local energy storage. In small power systems, such as those of vehicles and naval ships, power electronics constitute the dominant network interface element. In such systems, it is then advantageous to design the controls of the power electronics as well as any other network element to best utilize energy assets and to avoid system collapse. Many techniques to enhance power system stability are documented in the literature. Most deal with either source or load aspects, but to date there has not been a comprehensive control framework for all power system components. Such a framework must deal effectively with the interactions of multiple entities with conflicting interests and may be considered in a game theoretic context. This talk will discuss the representation of the interactions of multiple power system entities using a game theoretic setting in which "players" have to dynamically negotiate to achieve their desired goals. The controls of the individual loads are based on a geometric energy control method with the determination of the manifold based on the desired interaction. The potential research avenues stemming from this work will also be presented.
|
|
|
|
PM GENERATOR CHARACTERISTICS FOR OSCILLATORY ENGINE BASED PORTABLE POWER SYSTEM
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
Ari Zachas ---
Ph.D Graduate Student ---
Georgia Institute of Technology, School of Electrical and Computer Engineering ---
Room 50, Everitt Lab, 3 pm - 4 pm -------
Abstract: Portable and light weight power supplies that can be used in remote areas are becoming very useful in many applications, especially in areas where no other source of power is available. One method to overcome this problem is to keep stored power, such as batteries, on standby to be used when needed. This can be both cumbersome and inefficient, taking up unnecessary space and creating significant logistical difficulties for large scale implementation. A proposed solution to this problem is to make use of a system that converts chemical energy obtained from a combustion process to mechanical energy and is then further converted to electrical energy.
An ultra-portable power system driven by a meso-scaled internal combustion swing engine (MICSE) is introduced. The characteristics of a permanent magnet (PM) AC generator operating under oscillatory motion are shown and the velocity profile of the rotor is approximated by a simple mathematical function suitable for use in a FEA simulation. A generator topology is presented and the effects of certain parameters on the output characteristics are noted. The output power of the generator is estimated when connected to a basic 6-bridge diode rectifier circuit and the characteristics of the generator are experimentally validated.
---------------------------
Biography:
Ari Zachas obtained both his BSc and MSc degrees in Electrical Engineering at the University of the Witwatersrand in South Africa in 1999 and 2004 respectively. After graduating in 1999 he worked for a division of Anglo Coal as a graduate junior engineer for two years, after which he joined Siemens South Africa as a System Designer in the Industrial Solutions and Services division. Ari came to Atlanta in 2004 and started his graduate studies at the Georgia Institute of Technology in 2005. His research has been focused in the area of permanent magnet machine design and has incorporated the use of Finite Element Analysis tools to evaluate the performance and design of these machines
|
|
|
|
POST-CONTINGENCY VOLTAGE AND REACTIVE POWER APPROXIMATIONS USING SENSITIVITIES
|
|
Presented by
Pablo
Ruiz
in Spring 2007
|
|
4:00 ¨C 5:00 p.m., Room 50 Everitt Lab,
Abstract:
Operational reliability studies require the solution of post-contingency power flows. Fast approximation methods are useful in reducing the computational burden of contingency studies. Sensitivities serve to approximate real power flows and bus angle differences and provide an acceptable trade-off between accuracy and speed. In contrast, sensitivity-based approximation methods for reactive power and voltage have not been as successful, partially because equipment limits are ignored. In this presentation, we discuss the computation of voltage and reactive power flow sensitivities and their application to contingency studies. We use these sensitivities to construct piecewise linear estimates that effectively capture the effect of equipment limits. We present representative results using the IEEE 14 and 57-bus test systems. The results show that VAr limits may have a significant influence on post-contingency voltages and reactive flows.
|
|
<<click here to download presentation>>
|
|
TURBOTRANS ENHANCEMENT OF THE DYNAMIC PERFORMANCE OF DC/DC CONVERTERS
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
4:00 pm - 5:00 pm, ROOM 50, Everitt Lab Abstract:
Off-the-shelf DC/DC converters are having a difficult time meeting the transient response needs of recent high speed DSP’s, FPGA’s, and microprocessors. A typical off-the-shelf converter requires thousands of µF of added capacitance to meet these ICs’ transient specifications. Yet, these capacitors occupy valuable PCB area, drive costs up, slow system response time and cause unstable outputs. TurboTrans is a technology added to off the shelf DC/DC converters for allowing user-customizable feedback to dramatically reduce the capacitance needed to achieve these high-speed transient response targets, while eliminating the undesirable aspects of typical converter transient system development. The theory behind TurboTrans is presented and illustrated with animated Mathcad graphs. A comparison of the transient response with and without TurboTrans technology is shown for a module of actual off-the-shelf DC/DC converters.
Biography:
Charles DeVries graduated from the University of Illinois with a BSEE in 1994. He currently works as an engineering group leader for Texas Instruments’ Plug-In Power business unit in Warrenville, Illinois. In his eight years at Texas Instruments, he has developed numerous products for both the Isolated and Non-Isolated DC/DC converter markets. He is the lead contributor to TurboTrans technology, has published one paper, holds one patent and has two patents pending.
Chris Thornton currently works on advanced product development projects for Texas Instruments' Plug-in Power business unit in Warrenville, Illinois. Plug-in Power was originally Power Trends Inc. Chris joined Power Trends in 1998 as an Application engineer. The company became part of TI's High-Performance analog business when it was acquired in 1999. Chris immigrated to the United States in 1985 to work for Hamilton-Sundstrand, a division of United Technologies (formerly Sundstrand Aerospace), where he designed DC/DC converters for aircraft electric power systems. He has over 16 years of experience in the design and application of DC/DC converters. He has designed power supplies for the space shuttle "Endeavor" and the Boeing 777 and 737 passenger aircraft. He recently developed a high-voltage energy storage control module for systems designed to the new AdvancedTCA® platform for telecom and computing applications. Chris has a BSc. Bachelor degree in Electrical Engineering from Coventry University, United Kingdom.
|
|
|
|
A SURVEY OF RADIOISOTOPE BATTERIES
|
|
Presented by
Nicholas
Benavides
in Spring 2007
|
|
4:00 - 5:00 p.m., Room 50 Everitt Lab
Abstract:
Abstract:
Since the 1950¡¯s, radioisotope energy sources based on energy conversion processes other than nuclear fission/fusion have found application in unattended electrical energy sources. These devices rely on the energetic particle release involved in radioactive decay. Many methods exist for converting this kinetic energy into electrical energy, and several will be discussed in this presentation. Radioisotope thermoelectric generators (RTGs), based on the Seebeck effect, have been used in NASA deep-space probes and U.S. Navy remote beacons for several decades. RTGs account for most of the commercially developed radioisotope batteries. Recently, advances in microelectromechanical systems (MEMS) have led researchers to develop very small radioisotope batteries based on beta-voltaic semiconductor junctions as well as mechanical cantilever movement. These researchers have claimed that these devices may someday be used for ¡°on-die¡± power supplies internal to integrated circuit packages in consumer products such as cellular phones. This presentation will briefly explore the feasibility of such a product and discuss some of the safety claims. Additionally, an examination of the application of modern power electronic devices in direct charge collection will be presented.
|
|
<<click here to download presentation>>
|
|
DISCUSSION OF THE GRAINGER CENTER FOR ELECTRIC MACHINERY AND ELECTROMECHANICS COLLABORATIVE NETWORK: AN OVERVIEW OF MACHINES AND ENERGY ON A NATIONAL SCALE
|
|
Presented by
Guest
Speaker
in Spring 2007
|
|
TELE-SEMINAR Participation:
The connection will be available approximately 10 minutes prior to the start of the seminar. The audio connection is available toll-free at (866) 337-0370 or locally at the University of Illinois, (217) 265-9181. NetMeeting connection 128.174.112.5.
Philip T. Krein
Professor and Director
Grainger Center for Electric Machinery and Electromechanics
University of Illinois at Urbana-Champaign
Department of Electrical and Computer Engineering
Abstract:
During 2005-06, visits were made to six collaborating schools of the Grainger Center for Electric Machinery and Electromechanics (CEME), and to several other campuses with strengths in machines and electrical energy. This talk is first an overview of major activities at the respective schools:
Purdue University
University of California at Berkeley
Georgia Institute of Technology
The Ohio State University
University of Wisconsin ¨C Madison
Oregon State University
Key machines-related research efforts in each collaborating group will be summarized, with some discussion about infrastructure, situation within the respective campuses, and other aspects. Future-oriented energy work at each school will be summarized. There will be emphasis on discussion from the entire audience about major directions and issues in electrical energy research.
|
|
|
|
TIME-SCALE MODELING OF SWITCHING POWER CONVERTERS
|
|
Presented by
Jonathan
Kimball
in Spring 2007
|
|
Abstract:
There are often dual control objectives for switching power converters. Typically, output voltage regulation is the primary requirement. In some applications, the inductor current must be controlled to track a particular waveform. For example, a power factor correction (PFC) converter is controlled to have sinusoidal current whose magnitude changes so as to regulate the output voltage. Alternatively, slew rate limits may be imposed on the current to prevent damaging overshoot or other undesirable operating modes. The designer has only one control input, the switch state, to meet both control objectives.
We explore time scale modeling in the context of multiple control objectives. First, the Krylov-Bogoliubov-Mitropolsky (KBM) averaging will be used to separate the average evolution of the state variables from the ripple imposed by switching. Next, singular perturbation theory is applied to demonstrate multiple time scales. If the converter design meets specific criteria, two time scales exist. Capacitor voltage is the slow state variable and inductor current is the fast state variable. We discuss implications for converter and control design.
|
|
<<click here to download presentation>>
|
|
DESIGN AND ANALYSIS OF PULSE-WIDTH MODULATION TECHNIQUES FOR SPECTRUM SHAPING
|
|
Presented by
Xin
Geng
in Spring 2007
|
|
Switching power converters are designed to transform available AC(DC) power sources to DC (AC) waveforms required by the load end. The operation of switching power converters relies on the appropriate control of the semiconductor switches. Pulse-width modulation (PWM) serves to effectively perform the control of the semiconductor switches. However, the signal modulated by the conventional PWM scheme contains unwanted harmonics, which may cause electromagnetic interference and acoustic and vibration in motor drive applications. These effects are addressed with spectrum shaping so as to modify harmonic characteristics of PWM switching signals without, or only minimally, sacrificing the signal-band integrity. A particularly useful approach involves the application of double-Fourier integral analysis for the selective harmonic elimination and the electromagnetic interference suppression. We propose to use a reference-based PWM scheme, the so-called pre-distorted PWM, which can provide high-quality switching signals to fulfill some of the spectrum-shaping tasks. In addition, we investigate frequency-modulated PWM (FM-PWM), which shows potential for effectively implementing the spectrum-shaping tasks as well. The ultimate goal of spectrum-shaping technology is to provide the designer the ability to specify a desired harmonic spectrum and then to realize it using a proper modulation scheme. The results of Pd-PWM and FM-PWM bring us one step closer to understanding how to meet this goal.
|
|
<<click here to download presentation>>
|
|
CARBON AND CLIMATE ISSUES FOR THE ELECTRIC POWER SECTOR
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
Abstract
Increasing levels of greenhouse gases (GHG) - and the climate change they are causing - are real and they are a major problem. To stabilize concentrations, the world is going to have to reduce its emissions of CO2 and other GHGs by at least 90%. Over the coming decades, there will be pressure for changes in the nature and operation of the global energy systems, with pressure on the generation of electric power, which produces one third of US GHG emissions. Technology for carbon capture and sequestration (CCS) in the electric power sector can probably be made economically and environmentally viable. The current regulatory system is inadequate and will need to be improved. Public perception could be a major obstacle. Public education about CCS and about alternative ways to reduce CO2 emissions needs to start now.
Biography
Jay Apt is Executive Director of the Carnegie Mellon Electricity Industry Center at Carnegie Mellon University's Tepper School of Business and the CMU Department of Engineering and Public Policy, where he is a Distinguished Service Professor. He received an A.B. from Harvard College in 1971 and a Ph.D. in experimental atomic physics from the Massachusetts Institute of Technology in 1976. His research, teaching and consulting interests are in economics, engineering, and public policy aspects of the electricity industry, economics of technical innovation, management of technical enterprises, risk management in policy and technical decision framing, and engineering systems design.
|
|
|
|
A STATOR TURN FAULT TOLERANT-STRATEGY FOR INTERIOR PM SYNCHRONOUS DRIVES IN SAFETY-CRITICAL APPLICATIONS
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
The scope of this research is to increase the availability of interior permanent magnet synchronous motor (IPMSM) drives in safety-critical applications under stator turn fault conditions. This objective is achieved by a simple fault tolerant-strategy that does not result in the complete loss of availability of a drive in the presence of a stator turn fault. It is proposed that there will be no modification of hardware in the standard drive configuration.
An electric drive in a safety critical application, in which any anomaly can result in injury or death, is required to be highly tolerant to any failure. In practice, high fault tolerance of an electric drive can be achieved not only through high reliability, but also by providing the capability of maintaining uninterrupted operation under a fault condition.
Stator turn faults in the stator windings of a symmetrical three-phase AC motor have been considered one of the critical failures that need to be detected during its incipient stage and require appropriate remedial actions because of their potentially destructive characteristics. Furthermore, because of the presence of the spinning rotor magnets that cannot be turned off at will, a stator turn fault in IPMSMs creates special challenges.
A simulation model, which is capable of describing the behavior of an IPMSM drive with stator turn faults, has been developed in terms of phase variables, and an investigation on this kind of fault in IPMSM drives is provided using the developed simulation model.
In this research, it is shown that an adjustment to the level of the rotating magnetic flux in an appropriate manner can result in a significant reduction in the propagation speed of the fault and possible prevention of the fault from spreading into the entire winding. This would be accomplished without any hardware modification. Based on this principle, a stator turn fault tolerant- strategy for IPMSM drives maintaining drive's availability is proposed and validated through simulations. A brief discussion on the practical issues is provided. Furthermore, the basic idea of an on-line stator turn fault detection scheme for IPMSM drives will be introduced.
Presented by:
Youngkook Lee
Electrical and Computer Engineering
Georgia Institute of Technology
TeleSeminar
|
|
|
|
ELECTRIC DRIVE AND MACHINE INTEGRATION
|
|
Presented by
Brett
Nee
in Fall 2006
|
|
An increasing number of machines is being coupled to power electronic drives, with the electronics providing control over the torque and speed variable of the machine. The motivating factor for the increase in the coupling is the superior dynamical and steady-state performance that results. Typically, the systems are designed separately with the drive operating with a fixed DC voltage and current rating that appropriately match those of the machine. However, in practice, an integrated design procedure is undertaken only for high dynamic performance applications. There exist vast opportunities for improvement in the steady-state performance in the application of electric machines for residential purposes, especially of the single-phase induction type. An integrated residential design focuses on the steady-state performance aspects such as efficiency and the power factor. The presentation will provide insights into the aspects of electric drive and machine integration. Simulation results for a simple system with varying degrees of integration are given to illustrate the benefits of an integrated design approach.
|
|
|
|
DESIGIN-ORIENTED MAGNETIC EQUIVALENT CIRCUIT
|
|
Presented by
Marco
Amrhein
in Fall 2006
|
|
Advances in power electronics and in materials, together with the changing application requirements, are key drivers of rapid new developments in electric machines. Such developments are demanding adequate design tools, particularly computer-aided tools for designing electromagnetic structures. The modeling approach is an important consideration in the construction of these tools. Three approaches - analytical models, finite element models, and magnetic equivalent circuit models - are compared in this presentation. Analytical and finite element models have characteristics that significantly limit their usefulness. Magnetic equivalent circuits are flexible in terms of size and accuracy, have moderate computational complexity, and are easily parameterized. They are readily extendible to three-dimensional analysis. The theory of a general magnetic equivalent circuit model of an electromagnetic system is reviewed and its use in the development of a comprehensive three-dimensional framework is outlined. Results for inductor models are compared to those for finite element models and measurements. In addition, preliminary results for an induction machine model are presented. The comparisons indicate the superiority of magnetic equivalent circuits, corrected for local saturation, over finite element models.
|
|
<<click here to download presentation>>
|
|
OPTIMIZING POWER SYSTEM RESTORATION RESOURCES AND ACTIONS
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
Restoration of a large and interconnected grid from a complete shutdown is a highly complex operation involving many technical and non-technical constraints. Practical and generic computer tools to support system dispatchers in their decision-making are desirable. Topics related to a restoration strategy will include optimization techniques to maximize available generation capability subject to time-varying constraints during restoration, use of tie lines, and time to restoration. The presentation will draw on research using information from a case study.
|
|
|
|
USING TORQUE-RIPPLE-INDUCED VIBRATION TO DETERMINE THE INITIAL ROTOR POSITION OF A PERMANENT MAGNET SYNCHRONOUS MACHINE
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
In numerous applications, it is desirable to control permanent magnet synchronous machines (PMSM) without the use of a position encoder. Therefore, as computing power has enabled more sophisticated algorithm implementation, position-sensorless control (PSC) has received considerable attention. Of the challenges to achieve a robust PSC, arguably the most significant is the determination of the initial position of the rotor. Error in the predicted initial position can lead to reverse rotation or a low starting torque.
In this research, it is shown that a vibration sensor can be used to determine the initial position of the rotor. Specifically, a start-up excitation is derived that yields a position-dependent signature in torque-ripple-induced vibration. The vibration is at a level that is readily detectable yet of a sufficiently low amplitude and duration that it does not create an acoustic-noise-related nuisance. The conveniences of the proposed method include: 1) It is applicable to both salient and non-salient machines, 2) It requires no knowledge of machine parameters, 3) It can be used to estimate position under no-load operation, and 4) The stator currents required for position detection are well below their rated value. The method has been validated in hardware using a surface-magnet PMSM. Without knowledge of machine parameters, a maximum error of 2.1¡ã and average error of ¡À0.7¡ã (electrical) has been achieved using a start-up that requires approximately 50 ms to complete.
|
|
|
|
Legislative Nuclear Power Renaissance - What's going on in nulcear energy
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
The presentation is an overview of the recent history and current developments in nuclear systems for energy generation in the US and around the world. The talk will discuss the technological advances in the field, the impact of government and regulatory policies and the social-political implications of expanding nuclear energy. The repercussions of the recent change in focus of the US Global Nuclear Energy Partnership (GNEP) will be discussed, as well as recent developments in the civilian nuclear power field. Presented by Prof. James Stubbins.
|
|
<<click here to download presentation>>
|
|
GENERALIZED LINE OUTAGE DISTRIBUTION FACTORS
|
|
Presented by
Teoman
Guler
in Fall 2006
|
|
4:00 PM - Distribution factors play a key role in many system security analysis and market applications. The injection shift factors (ISFs) are the basic factors that serve as building blocks of the other distribution factors. The line outage distribution factors (LODFs) may be computed using the ISFs and, in fact, may be iteratively evaluated when more than one line outage is considered. The prominent role of cascading outages in recent blackouts has created a need in security applications for evaluating LODFs under multiple-line outages. We develop an analytic, closed-form expression for and the computationally efficient evaluation of LODFs under multiple-line outages, which we refer as generalized LODFs, or GLODFs. The GLODFs are useful for both real-time and offline environments for security analysis and control as well as market applications. In this presentation, we focus on a particular application of the GLODFs to the analysis of topological impacts of outaged lines on system connectivity. Specifically, the GLODFs are effective in the detection of island formation and the identification of the causal factors when a power system is subject to multiple-line outages.
|
|
|
|
Ocean Wave Energy Conversion - A Survey
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. The presentation gives a systematic and comprehensive overview of wave energy converters as opposed to ocean current energy converters. The point absorber and oscillating water column wave energy converter devices are addressed with regards to commercial prospects, environmental concerns, current state-of-the art, and further research areas. Thereby, the presentation seeks to enhance investigation of results obtained in other fields in the ocean wave energy conversion setting and to stimulate research on topics that have not been in the focus so far. (Presented by Annette Muetze, University of Wisconsin-Madison).
|
|
<<click here to download presentation>>
|
|
SCADA Cyber security testbed development
|
|
Presented by
Matt
Davis
in Fall 2006
|
|
|
|
<<click here to download presentation>>
|
|
RTO EMS and Market Systems
|
|
Presented by
Guest
Speaker
in Fall 2006
|
|
Presented by Nivad Navid, Midwest ISO.
|
|
<<click here to download presentation>>
|
|
A Preliminary Investigation of Computer-Aided Schwarz-Christoffel Transformation for Electric Machine Design and Analysis
|
|
Presented by
Tim
O'Connell
in Summer 2006
|
|
An alternative method to finite element analysis (FEA) for electric machine design and analysis is presented that applies Schwarz-Christoffel (SC) conformal mapping theory using the SC Toolbox for MATLAB® that has appeared in the previous literature. In this method, a two-dimensional (2D) developed machine cross-section domain is mapped via SC transformation to a concentric cylinder domain where solutions for the electromagnetic (EM) fields are known. These solutions are mapped back to the original domain, thus solving the original problem. All mapping is done via the SC Toolbox. Examples are given in which the procedure is used to calculate the EM field in the air gap of and the force on the rotor of various 2D developed machine cross-sections. The numerical accuracy of the results is verified by comparing the solutions as the air gap gets small with magnetic equivalent circuit (MEC)-derived coenergy solutions.
|
|
<<click here to download presentation>>
|
|
Investigating the utility of Schwarz-Christoffel mapping theory for electric machine design and analysis
|
|
Presented by
Tim
O'Connell
in Spring 2006
|
|
With the increased availability of inverters, exotic permanent magnet (PM) materials, and low-cost, precision manufacturing, the domain of achievable electric machine designs is increasing at a high rate. With new design possibilities must come the advancement of available design tools. While finite element analysis (FEA) is a mature, widely available machine analysis tool, its utility in design is less obvious because with it parameter optimization requires many time-consuming design iterations. An alternative method is investigated and will be discussed here. In this method, Schwarz-Christoffel (SC) mapping theory is applied to the machine design problem and implemented using the SC Toolbox for MATLAB®. SC mapping is a complex analysis tool that allows us to map a simple geometrical domain in which an analytic field solution is available into a complicated machine cross-section domain, thereby solving the field problem in that domain. The chief advantages of the SC approach are: efficiency at high accuracy, ease of use in unbounded regions, and the incorporation of singularities that can significantly hinder the success of general-purpose methods. More generally, the SC method deserves research attention because it produces an exact field solution, which is advantageous when it is necessary to accurately calculate machine forces.
In this talk, a brief history of the uses of SC theory in machine design will be given. The basic process of designing with the SC toolbox and some examples will also be presented. The method’s advantages and disadvantages as compared to FEA as we understand them now will be discussed.
|
|
<<click here to download presentation>>
|
|
Power converter design issues for portable low power fuel cell systems
|
|
Presented by
Nicholas
Benavides
in Fall 2005
|
|
Proton exchange membrane (PEM) fuel cell systems have not yet penetrated the low power (<50 W) portable energy source market, largely due to complexity of control and the balance of plant systems required. Even though the fuel cell and fuel container may scale down well, the pumps, blowers, and power converters required may dominate the mass of the system. In general, efficiency is not the correct figure of merit for portable systems, and total system mass including fuel should be minimized. Two optimizations will be explored: the secondary energy storage and the fuel cell converter inductor design.
Fuel cells typically respond very poorly to changes in load, and the power converter and secondary energy storage must meet all transient load requirements. Any power loss incurred by the secondary energy storage must be accounted for by additional fuel. There is therefore an optimum amount of energy storage that depends on load profile. This will be discussed in this presentation. The tradeoff between efficiency and mass of the converter will be explored, with the goal of achieving the minimum mass of both the converter and fuel. The effort was focused boost converters; however the method can be applied to any converter topology. In general, the optimum efficiency of the converter will be shown to depend on the mission length.
|
|
<<click here to download presentation>>
|
|
Hurricane Katrina's Damage: Assessment of Power Infrastructure for Distribution, Telecommunications and Backup, With On-Site Data
|
|
Presented by
Alexis
Kwasinski
in Fall 2005
|
|
On August 29th, 2005, Hurricane Katrina struck the Mississippi and Louisiana coast with winds over 140 mph and storm surge reaching 25 feet in some areas. Since then, there has been extensive media coverage of the hurricane’s effects of power outages and communication networks’ loss of service and how these effects hampered the rescue and relief efforts leading to loss of property and life. The impact on power and communication networks as well as the consequences of extended outages in the aftermath of disasters of this magnitude illustrates the need for further contingency planning. In the past, there has not been much research on disaster damage and restoration of telecommunications systems. Neither have there been many studies on how the reliability of communication systems in extreme conditions is related with the power supply and which is the main failure mode.
This presentation is based on an NSF-sponsored research that attempts to extend the knowledge of catastrophic disasters on the transmission grid, the electrical distribution system, the telecommunications power infrastructure, and backup systems. This presentation shows significant observations and information both gathered from an on-site survey conducted between October 17th and October 23rd in the area affected by Hurricane Katrina and from other sources. The collected information is used to asses the damage in the electrical power infrastructure for distribution, telecommunications and back-up and to determine the extent of the restoration already in place. Some preliminary analysis and conclusions about telecommunications networks’ failure modes, back-up systems behavior, and restoration practices usefulness will also be presented.
|
|
<<click here to download presentation>>
|
|
Doubly Fed Induction Machine Analysis for Power Flow Control
|
|
Presented by
Brian
Raczkowski
in Fall 2005
|
|
The analysis and simulation of a doubly-fed induction machine used as a power flow control device are presented. This is a system that transfers power between one power system area and another using a doubly-fed induction machine as a rotary transformer containing rotor and stator windings. The ability to control the power flow by adjusting the rotor shaft angle is demonstrated. A test system was developed and experiments were carried out on an actual machine.
|
|
<<click here to download presentation>>
|
|
Security Criterion Impacts On The Day-Ahead Market Performance In The ISO-New England
|
|
Presented by
Teoman
Guler
in Fall 2005
|
|
A key factor impacting the economic efficiency of an electricity market is the security criterion used to comply with the power system reliability requirements. We present a summary of our studies on the assessment of the impacts on the Day-Ahead Market performance of imposing different security criteria in the ISO New England. We examine 3 specific security criteria: the n-1 and the n-2 security criterion and the actual security criterion employed by the ISO New England. For each security criterion, we evaluate the benefits, the costs and the market efficiency and unit commitment impacts over a month period. The comparative analysis of the results demonstrates the interrelationships between the market efficiency and the choice of security criterion. This investigation quantifies the dependence of market efficiency on the security criterion. In addition, our studies indicate the issues that would be beneficial to further investigate.
|
|
|
|
Initialization Schemes for Newton-Raphson Power Flow Solvers
|
|
Presented by
Zeb
Tate
in Fall 2005
|
|
This presentation discusses the global convergence problem of the Newton-Raphson algorithm in power system applications. First, a brief overview of the Newton-Raphson algorithm is provided, with particular attention paid to its convergence behavior. The specific aspects of the Newton-Raphson algorithm in power flow applications are then reviewed. The methods used to address the global convergence problem are discussed, with particular emphasis placed on a decoupled, linear iterative scheme implemented in several power system software packages. A new method employing continuation techniques is introduced and results obtained with this method are provided for various systems including a 2-bus, the IEEE 118-bus, and a large 10,274 bus test systems. The simulation results illustrate the viability of the new method in addressing the issue of global convergence. Possible directions for future work on this problem are presented.
|
|
<<click here to download presentation>>
|
|
Development of an automated first-principles design tool for electromechanical devices
|
|
Presented by
Tim
O'Connell
in Spring 2005
|
|
This work re-explores first-principles machine design by implementing a continuum electromechanical model with Mathematica symbolic software. With the present availability of inverters, new permanent magnet materials, and low-cost, precision manufacturing, it is both wise and necessary to re-examine machine design using first-principles to find opportunities for improvements. In my talk, I will give a brief historical background of the development of the induction machine, and describe how early machine researchers were forced to make design simplifications due to the mathematical complexities involved in using first-principles analyses. Today, many of the impediments to these types of analyses can be removed by using symbolic software. Specifically, in 1981 Melcher developed a continuum electromechanical model that could in principle be applied to layered structures with any number of layers. In practice, however, the algebraic bookkeeping necessary to solve the equations for a structure with anything more than two layers was manually intractable. Today, Mathematica eliminates this obstacle by automating the symbolic solution process, and I will describe a Mathematica program developed here that does this. I will also summarize an experiment using a double-stator linear induction motor (LIM) conducted to verify the implemented model’s accuracy in predicting force density. The talk will conclude with a discussion of both the model’s limitations and goals for future research to reduce these limitations.
|
|
<<click here to download presentation>>
|
|
Ripple Correlation Control in Photovoltaic Systems
|
|
Presented by
Trishan
Esram
in Spring 2005
|
|
Over the last decades, much attention has been given to solar energy. To justify the high costs of photovoltaic (PV) systems over the long run and to extract maximum power out of the PV panels, several maximum power point tracking (MPPT) methods have been proposed and implemented. Among these MPPT methods, ripple correlation control (RCC) has shown several advantages. This talk gives an overview of the different MPPT methods, with their pros and cons. The theory behind RCC is discussed and then the hardware implementation is described. We present experimental results to illustrate the capabilities of RCC. The advantage of tracking the maximum power points (MPPs) of individual PV panels independently instead of tracking the resulting MPP of the PV panels connected in series is demonstrated with the experimental results.
|
|
<<click here to download presentation>>
|
|
System Security Criterion Influence on Market Performance
|
|
Presented by
Teoman
Guler
in Spring 2005
|
|
|
|
<<click here to download presentation>>
|
|
PERFORMANCE AND CYCLE LIFE ANALYSIS OF LITHIUM ION BATTERIES
|
|
Presented by
Grant
Pitel
in Fall 2004
|
|
Two attractive characteristics of lithium ion batteries are that they are a renewable energy source and they have high energy density. The demand for these batteries in portable electronics and aerospace has been growing steadily. It is common practice to stack batteries in series to achieve a desired output voltage but how does this affect the life of the battery? This presentation emphasizes the methodology and design of custom test equipment used to assess battery cycle life. It is already known that cycling lead acid batteries without the proper electronics to equalize the charge on each cell diminishes capacity. By analyzing charge and discharge data we will deduce the cause for cells in a stack to unequalize. We then develop a general method for determining battery equalizer design constraints, which is applicable to lithium ion and all other battery chemistries.
|
|
<<click here to download presentation>>
|
|
Differences in Performance of the Optimal Multiplier for Polar and Rectangular Coordinates
|
|
Presented by
Zeb
Tate
in Fall 2004
|
|
Studies of the optimal multiplier (or optimal step size) modification to the standard Newton-Raphson load flow have mainly focused on highly stressed and unsolvable systems. This presentation extends these previous studies by comparing performance of the Newton-Raphson load flow with and without optimal multipliers for a variety of unstressed, stressed, and unsolvable systems. Also, the impact of coordinate system choice in representing the voltage phasor at each bus is considered. In total, four solution methods are compared: the Newton-Raphson algorithm with and without optimal multipliers using polar and rectangular coordinates. This comparison is carried out by combining theoretical analysis of the optimal multiplier technique with empirical results for 2 bus, 118 bus, and 10,274 bus test cases. These results indicate that the polar Newton-Raphson load flow with optimal multipliers is the best method of solution for both solvable and unsolvable cases.
|
|
<<click here to download presentation>>
|
|
Electricity Market Monitoring
|
|
Presented by
Teoman
Guler
in Fall 2004
|
|
|
|
<<click here to download presentation>>
|
|
“Cascadability” Index using Linear Contingency Methods
|
|
Presented by
Matt
Davis
in Fall 2004
|
|
|
|
<<click here to download presentation>>
|
