MIT Reports to the President 1999–2000
The mission of the Laboratory for Electromagnetic and Electronic Systems (LEES) is to be the focus for research and teaching in electric energy from its production through its processing to its utilization, and in electromechanics from the macroscopic through the microscopic levels. Electric energy and electromechanics are defined broadly to include power systems monitoring and operation; automatic control; power electronics; high voltage engineering; and conventional, continuum and biological electromechanics. Much of the work of the laboratory is experimental, and industrial sponsorship represents a large fraction of the laboratory’s support. The laboratory’s professional staff consists of 7 faculty from EECS, 1 Principal Research Engineer, 1 Principal Research Scientist, 2 Research Scientists, and approximately 50 graduate students. The laboratory faculty and most of the staff are heavily involved in both undergraduate and graduate teaching. Faculty from the departments of ME, CE, MS&E and NE are collaborators in many of the laboratory’s programs, and there are extensive joint activities with the Microsystems Technology Laboratory (MTL) and the Laboratory for Information and Decision Systems (LIDS).
During the past year the laboratory has experienced a 35% increase, to 46 companies, in its Consortium on Advanced Automotive Electrical/Electronic Components and Systems (the "Automotive Consortium") membership, demonstrated a radical innovation in automotive alternator design, developed a new magnetic field based concept for nanoactuators, shown that magnetically triggered gels can function as active vibration dampers, and developed a new model for exploring cascading failures in complex interacting electric power networks.
Professor John G. Kassakian, Principal Research Scientist Dr. Thomas A. Keim and Research Scientist Dr. David Perreault lead the laboratory’s work in automotive electrical and electronic systems. This work is sponsored primarily through the laboratory’s Consortium on Advanced Automotive Electrical and Electronic Components and Systems. The consortium membership now numbers 46, an increase of 12 from one year ago, and represents almost all of the world’s major automobile manufacturers and component suppliers.
Dr. Perreault and graduate student Vahe Caliskan have developed a new design for automotive alternators that enables dramatic increases in alternator output power and substantial improvements in efficiency. The new design, which uses a switched-mode rectifier, preserves the simplicity and low cost of conventional alternator designs and can be manufactured within the existing manufacturing infrastructure. Improvements of a factor of two in output power and 20 percentage points in efficiency have been experimentally demonstrated. Higher power capability is a critical issue for future vehicles, while the improved efficiency is projected to reduce the consumption of gasoline in the United States alone by more than 2 billion gallons/year. The new technology also provides other improvements of central importance to future 42 V electrical systems, such as greatly improved transient control and the ability to use the alternator to jump charge the high-voltage battery from a low-voltage source. These developments have resulted in three patent filings, and are expected to greatly facilitate the rapid introduction of high-power and high-voltage electrical systems in automobiles.
Research Assistant Edward Lovelace completed a doctoral thesis on the design of interior permanent magnet crankshaft starter alternators. Ford Motor Company is building several motors designed by Dr. Lovelace, and one will be tested in LEES.
The consortium sponsored three two-day meetings during the past year. One meeting was held in Stuttgart, Germany, co-sponsored by Robert Bosch GmbH. Another meeting, held in Greenville-Spartanburg, South Carolina, and co-sponsored by BMW included a visit to their North American manufacturing site. The third meeting was held in Vancouver, British Columbia, with assistance provided by iQ Power Technology. Approximately 175 people attended each of these meetings. During the next 12 months, meetings are scheduled for Nagoya, Lisbon, and Detroit.
The laboratory successfully concluded its strategic alliance with Ford on accelerating the adoption of a 42 V automobile electrical system standard. A virtual engineering workgroup comprising approximately 25 organizations in 34 different geographical locations worked on the topics of battery connections, jump starting, and energy management. Results of this project were presented in a jointly-authored paper at the First International Congress: 42 Volt PowerNet in Austria.
Professor Kassakian co-authored an article on the new automotive electrical system which appeared in IEEE Spectrum. He also delivered a keynote address on the application of power electronics in automobile electrical systems at the IEEE Applied Power Electronics Conference.
Utility industry restructuring has placed an intense focus on achieving economically optimal system operation by employing new and more sophisticated control and monitoring strategies. LEES has been making significant contributions to the solutions of problems of power system modeling, economic control, and apparatus monitoring.
Professors Bernard Lesieutre and George Verghese, along with several graduate students, have completed one year of a multi-year research effort funded by EPRI and the Department of Defense, and organized in a consortium with Caltech, UCLA and UC Santa Barbara, to study complex interacting networks and systems. The MIT effort focuses on power networks, as well as networks that couple into these, and specifically on problems related to cascading failure in such networks. One very promising outcome of the work so far has been the introduction and elaboration of a so-called "influence model" in the doctoral thesis of graduate student Chalee Asavathiratham, providing a tractable representation for networked Markov chains (e.g. representing transitions between normal, alert and failed states at individual nodes of a network). The influence model is rich enough to capture a variety of interesting behaviors, but tractable because it can be analyzed at successively more detailed levels. Professor Lesieutre has been invited to present the group’s work at the IEEE Summer 2000 Power Meeting, and Professor Verghese has been invited to give a one-hour talk on power networks at a workshop on complex networks this summer at the Santa Fe Institute.
Professors Lesieutre and Verghese have also completed an extended research project for Electricité de France on reduction of large dynamic models of power systems, obtaining for the first time reductions by factors of 10 or more in computation time, while preserving satisfactory accuracy. It is anticipated that their Synchronic Modal Equivalencing (SME) framework will find use in dynamic security assessment in utility control centers; initial discussions on this have begun with the national control center in France.
Graduate student James Hockenberry, the first Grainger Fellow supported under a gift from the Grainger Foundation, has completed a project under the supervision of Prof. Lesieutre that demonstrates the feasibility of performing uncertainty analysis on large-scale power systems. He developed a technique for identifying critical uncertainties, which when used with reduced-order modeling methods reduces the necessary computation times by orders of magnitude. This is an enabling technology that allows uncertainty analyses to be performed on these large systems with numerous uncertain parameters.
Professor Verghese and his doctoral student, Christoforos Hadjicostis (now Assistant Professor at the University of Illinois in Urbana), have developed systematic coding-based approaches to the introduction of redundancy for fault tolerance in a variety of computational and dynamic systems. A paper describing the potential application of this to power system monitoring via Petri net embeddings is to appear in the IEE Proceedings, and a monograph growing out of the thesis is to be published this year by Kluwer.
A new method for the early detection of wearout and need for service, which is applicable to power transformers and other oil insulated power apparatus, has been developed by Principal Research Engineer Dr. Chathan Cooke and graduate student Timothy Cargol. The specific goal is the automated in-service detection of degradation of insulating oil used in power apparatus. An operating system has been demonstrated in laboratory studies and will soon be applied on an in-service transformer as a demonstration. Automated operation with automated reporting of troubles to the maintenance department via internet connections make this system especially attractive to new deregulated utilities since it enables maintenance-on-need compared to the present method of fixed time between manual inspections. The automated operation and network communications provide an opportunity for significant cost savings as well as more reliable operations. The work is sponsored by Entergy Services Inc.
In collaboration with Professor Les Norford and post-doctoral associate Steven Shaw, Professor Steven Leeb has demonstrated the first practical field applications of nonintrusive power monitoring technology for diagnostic applications using sophisticated state and parameter estimation algorithms. These techniques permit the identification of energy savings opportunities and equipment failures in building heating and ventilation systems. They are being developed to enhance "green" building operation and to permit the scheduling of maintenance in advance of critical failures. Field tests have been conducted on and off campus, and will expand to 10 or more new sites in the coming year with funding from the California Energy Commission.
Dr. Cooke and undergraduate Daniel Santos have begun a new project to reduce the adverse effects of lightning on overhead power transmission and especially the effects on substation apparatus located at the end of a power line. This effort uses a new technique to add a frequency selective loss element that reduces the transient surges at substation apparatus. While existing systems are effective they involve overvoltage arrestors only and are thus limited in their abilities. The addition of a frequency dependent factor to the transient protection results in improved protection and less power outages. Bench size models have been used to demonstrate the method and larger scale tests are being planned.
Dr. Perreault, along with graduate student Joshua Phinney, has developed a new actively-tuned filter technique for power electronic converters. The new technique allows the use of small notching power filters instead of the bulkier low-pass types that are conventionally employed, resulting in smaller passive component size and reduced converter size, weight, and cost. This new approach is expected to be valuable in a wide range of power electronics applications.
Graduate student Timothy Neugebauer and Dr. Perreault have developed a CAD tool for optimized design of power converters. This new tool has been employed to design a highly optimized dc/dc converter for dual-voltage automotive electrical systems. The optimized converter is less than one quarter the size of previously developed prototypes. Dr. Perreault and Mr. Neugebauer are working with Intronics Corporation to manufacture these converters for use by automotive consortium member companies.
In collaboration with a colleague at Lucent Technologies, Professor Verghese has developed a framework for digital control of paralleled power converters, such as those found in battery plants for telephone exchanges and outdoor base stations. Implementations based on this framework have been crucial to obtaining robust, high performance controllers for the modern battery plants that Lucent currently sells in significant numbers.
Professor Verghese has coedited (with Prof. Soumitro Banerjee of IIT, Kharagpur) an IEEE Press volume on "Nonlinear Phenomena in Power Electronics: Attractors, Bifurcations, Chaos and Nonlinear Control," with contributions from nearly 30 international researchers; the book is to appear later this year.
Professor Leeb and graduate student John Rodriguez are using magnetically triggered gels to develop active vibration dampers. These semi-active dampers have the special property that they can be tuned to damp over a range of vibration frequencies using an applied magnetic field. They can also be made responsive to other environmental stimuli, including light, heat, and the presence of specific chemicals. Successful tuning was demonstrated for the first time this year. Design and experimentation is currently under way to develop dampers suitable for use in transportation applications, e.g., as adaptive, vibration-damping engine mounts in automobiles.
Professor Markus Zahn has recently developed new magnetic field based concepts for realizing nanomotors, nanogenerators, nanopumps, nanoactivators, and other similar nanoscale devices which can be used in new electronic, engineering, biological, and medical applications. This discovery has resulted from his research on magnetic field dependent viscosity in ferrofluids including the possibility of zero or negative effective viscosity. The nano scale of these devices arises from the fact that ferrofluid magnetic particles are of order 10nm in diameter. Proposals on this subject have been submitted to NSF and NASA.
Graduate students Steven Nagle and Luc Frechette, and Professor Jeffrey Lang, in collaboration with colleagues in the MIT Gas Turbine Engine Program, have developed and demonstrated micro-scale electric induction motors for use in micro-scale turbomachinery. These motors exhibit significantly greater torque and power densities, and efficiencies, than do existing electric micro-scale motors.
Graduate student Hur Koser and Professor Jeffrey Lang, in collaboration with Professor Mark Allen and his students at the Georgia Institute of Technology, and colleagues in the MIT Gas Turbine Engine Program have completed the design of micro-scale magnet induction motors and an electroplating process to fabricate them. These motors should exhibit torque densities that are significantly superior to those of existing electric micro-scale motors. Fabrication of the first motor is currently underway, and testing is expected during the next several months.
Graduate student Jo-Ey Wong and Professors Martin Schmidt and Jeffrey Lang have completed their development of a micro electromechanical relay for switching power in low-voltage applications. Their relay, which was demonstrated earlier this year, is electrostatically controllable, and hence it dissipates zero control power in its on state. Its on-state threshold voltage is lower than any other electrostatically-controlled relay, and its on-state current capacity is higher than any other such relay.
Tim Denison and Professor Leeb are collaborating with Harvard University and the Rowland Institute to develop circuitry applicable for DNA sequencing and polymer identification. A new pico-amp electrometer has been designed that, in combination with a nano-pore formed in a lipid membrane, has been successfully used for the first time this year for genetic sequence recognition.
Senior Research Scientist Dr. Marija Ilic has left the laboratory to join colleagues in the Laboratory for Information and Decision Systems (LIDS).
Ms. Kiyomi Boyd has joined the laboratory as Senior Secretary and assistant to the Director. Her fluent Japanese has been a valuable asset as Japanese membership in the Automotive Consortium has grown.
For part of the past academic year Professor Zahn was a ville de Paris scholar and held La Chaire Paris-Sciences at the Ecole Superieure de Physique et de Chimie Industrielle (ESPCI) in France, where he also received the ESPCI medal for Paris Sciences 2000.
Professor Leeb was selected as a Discover Magazine award finalist for his ARCLight fluorescent lamp ballast. This ballast modulates the arc in a fluorescent light to establish an optical data network using conventional room lighting. The technology has been used, among other applications, to provide navigation information to the blind in public venues.
Professor Kassakian received the IEEE Millennium Medal for his contributions to the profession and service to the Power Electronics Society.
John G. Kassakian
MIT Reports to the President 1999–2000