MIT Reports to the President 1998-99

LABORATORY FOR ELECTROMAGNETIC AND ELECTRONIC SYSTEMS

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 Senior Research Engineer, 5 research staff, 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 Energy Laboratory. During the past year the laboratory has experienced a substantial expansion of its automotive related research, demonstrated a sensor technology capable of detecting plastic landmines, demonstrated an actively controlled polymer gel synthetic muscle, and successfully applied advanced signal processing techniques to the evaluation of insulation integrity in high voltage power cables.

Professor John G. Kassakian and Research Scientist Thomas A. Keim 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 34, an increase of 14 from one year ago. Eight of these new members are from Japan, which is significant because these companies represent the beginning of Japanese participation in the dialog about the design of the electrical system of future cars. The consortium sponsored three two-day meetings, one hosted by Mercedes Benz at their M-class manufacturing facility in Birmingham, Alabama, another by Delphi Automotive Systems in Indianapolis, Indiana and the third by Renault in Paris. An important milestone achieved by the consortium was reaching international consensus on 42 V as the standard for advanced automotive electrical systems. The agreement was contained in a press release in both English and Japanese and distributed internationally.

The laboratory's strategic alliance with Ford to accelerate the adoption of a 42 V standard has been expanded to 10 companies. This virtual team activity now spans 9 time zones. Standards for a jump starting system and battery terminal configurations have been proposed.

Working with graduate student Tim Neugebauer, Post Doctoral Fellow Dr. David Perreault has continued developmental work on power converters for use in 42 V automotive electrical systems. Two prototype converters have been delivered to Ford, and have undergone extensive testing as part of their experimental 42 V electrical system.

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.

Senior Research Scientist Marija Ilic has coedited a book entitled Electric Power Systems Restructuring: Engineering and Economics, published by Kluwer Academic Publishers, and coauthored with former graduate student Eric Allen the monograph Price-Based Commitment Decisions in the Electricity Market published by Springer-Verlag.

Professors Bernard Lesieutre and George Verghese, with visiting Electricité de France (EDF) engineer Marek Teste, graduate student James Hockenberry, and other students, have largely completed implementation of a novel approach to reduced-order modeling of power systems. The improvements embodied in the present version, and its realization in a widely-used simulation package that EDF has developed, have brought the approach past a critical threshold. Tests on very large models (10,000 variables) are in progress, and if the results there are as good as those already obtained for intermediate-sized models (500 variables), then our approach will be a major improvement over the state of the art for this important problem.

Professors Lesieutre and Verghese have also received a multi-year grant from EPRI and the Department of Defense to develop and study models and paradigms (as suggested by, for instance, percolation theory) for cascading failure in power networks. The project is to be carried out in a five-university consortium led by Caltech.

The LEES research program on power apparatus monitoring is becoming more visible worldwide, as a company in Austria and two companies in the UK have expressed serious interest in participating. Principal Research Engineer Chathan M. Cooke and Research Engineer Wayne H. Hagman have added Consolidated Edison Company of New York to the loose consortium funding on-line power transformer performance and condition monitoring in LEES. Coincident with progress in deregulation of portions of the power grid, interest has grown in the methods developed in the laboratory to aid in equipment utilization, maintenance and failure detection. To facilitate their research, and insure its relevance to the utility industry, Dr. Cooke and Mr. Hagman are installing monitoring equipment on transformers and load tap changers (LTC's) in substations of Boston Edison Company, Entergy Services, Inc., and Consolidated Edison. Data acquired from these devices is aiding the host utilities in the usage and maintenance of their transformers and LTC's, while providing the information needed for Dr. Cooke and Mr. Hagman to develop intelligent sensors and model-based techniques for real-time thermal loading, maintenance interval recommendations, and incipient failure detection.

ELIN Transformatoren of Weiz, Austria has licensed the technology of a new diagnostic technique developed by Dr. Cooke, and has provided a continuation research effort with the intent of bringing the technology to market. This new diagnostic technology of on-line partial discharge measurement employs modern high-speed data acquisition and then modern signal processing to discern and evaluate the minute partial discharge events of interest. Successful demonstration of the technique on three different large transformers during this year has provided further evidence that automated in-service systems based on this technology can be developed.

Professor Steven Leeb, graduate student Steven Shaw, and students Christopher Salthouse and Christopher Laughman, are continuing field testing with several nonintrusive monitoring prototypes. Installations have been made on campus at Next House and East Campus Dormitories, and also at a remote facility in Iowa for testing ventilation system monitoring. Substantial progress has been made to implement real-time load performance and diagnostic monitoring. A complete monitor was installed in a test automobile this year, and will continue to be used in the coming year to explorereal-time diagnostic and performance monitoring in transportation systems.

Graduate student Edward Lovelace, Dr. Keim and Prof. Jeffrey Lang, in collaboration with Prof. Thomas Jahns of the University of Wisconsin, have continued their development of a combined high-power starter-alternator for future automobiles that is more compact, more efficient and less expensive than a scaled-up version of traditional starters and alternators. The design of their interior permanent-magnet synchronous machine, which is based on advanced nonlinear magnetic models, is nearly complete; an experimental demonstration is planned for next year.

Graduate student Tracey Ho and Profs. James Kirtley and Jeffrey Lang have completed their study of idling losses in high-speed permanent magnet synchronous machines. The goal of their project was to develop and verify loss models that will enable the design of flywheel energy storage systems that can store energy for extended periods of time. The models have been completed and experiments have been conducted to verify their accuracy.

Professor Steven B. Leeb, in collaboration with Professor Toyoichi Tanaka of the Center for Materials Science and Engineering, and with graduate students John Rodriguez and Tim Denison, continues to explore applications of polymer gels as actuators and sensors. Professor Leeb was awarded a second patent this year for the design of a drug delivery device employing gels that exhibit a phase-transition in response to an applied magnetic field. Magnetically responsive gels have been used this year to demonstrate antagonistic muscle papers suitable for constructing servomechanisms with motion paths and control capabilities analogous to biological systems. Preliminary experiments have begun to evaluate a new polymer fluid, whose viscosity increases with temperature, as an active material in torque converters and vibration dampers. Tim Denison and Professor Leeb are collaborating with Harvard University and the Rowland Institute to develop circuitry applicable for DNA sequencing and polymer identification.

Through analysis, Prof. Zahn has reaffirmed past measurements that ferrofluids in ac and traveling wave magnetic fields can be pumped, and that the effective fluid viscosity can be decreased to zero and negative values as a function of magnetic field amplitude, direction, and frequency. This phenomena is expected to be applied to MEMS research using magnetic liquids.

Graduate student Steven Nagle and Prof. Jeffrey Lang, in collaboration with many students, staff and faculty at MIT, have continued their development of micro electrostatic induction motors for use in micro turbomachinery. These motors should exhibit significantly greater power densities and efficiencies than existing micro motors. The experimental operation of these motors has been demonstrated and experiments are now underway to quantify their performance.

Graduate students Oscar Mur-Miranda, Rajeevan Armirtharajah and Scott Meninger, and Profs. Anantha Chandrakasan and Jeffrey Lang have continued their development of micro electromechanical systems to convert ambient vibration energy into electric energy for powering autonomous electronics. This year they have fabricated and begun to test the electromechanical energy converter, and they have completed the design, fabrication and testing of very low-loss power electronics to control the converter.

Postdoctoral research associate David J. Perreault, working with graduate student Mingjuan Zhu, developed a new active ripple filtering technique for power electronic converters. The new technique permits the use of substantially smaller passive filter elements, resulting in reduced converter size, weight, and cost. Using this technique resulted in a factor of five reduction in total filter mass,while substantially improving the converter transient performance. This new approach is expected to be valuable in a broad array of power electronics applications.

A third 42/14V converter has been undergoing testing in LEES, and its use for implementing energy management in dual-voltage automotive electrical systems has been demonstrated. Dr. Perreault and graduate student Timothy Neugebauer have also developed a CAD tool for optimized design of power converters for this application. In addition to allowing the rapid design of highly-optimized converters, this tool will allow automobile manufacturers to rapidly assess the effects of system-level parameter variations on the size, weight and cost of the power electronics.

Professor Verghese and Dr. Perreault, along with former graduate student Ankur Garg, have shown how to extend the stability analysis of identical paralleled power converters to the case where current sharing is accomplished through nonlinear means. The preferred implementation in industry involves a chip that implements a nonlinear control scheme covered by this analysis.

Professor Leeb and graduate student John Rodriguez are exploring applications of inductively coupled power electronic drives for servomechanical systems. Adaptive controllers have been developed and tested for a range of servomechanisms, and are currently being extended for use in active vibration dampers and torque converters for transportation systems. With undergraduate Ann Mitzel, the basic inductive coupling techniques were applied to the development of a magnetically coupled key and lock entry control system.

Professors Zahn and Lesieutre working with recently graduated Ph.D. students Alex Mamishev and Yanqing Du, have developed improved dielectrometry sensor designs and parameter estimation that can measure profiles in dielectric permittivity, conductivity, and related physical properties. The performance of these sensors has been demonstrated in measuring the time and space development of moisture diffusion in transformer oil and pressboard. Additionally, large scale versions of the dielectrometry sensor have demonstrated the ability to detect buried low-metal-content and plastic landmines.

Dr. Cooke has developed a new diagnostic tool employing fast nanosecond pulse high-voltage technology and signal processing to establish the quality of oil insulation. Sponsored jointly by Entergy and Consolidated Edison of NY, it provides remote automated in-service measurement of oil dielectric strength, and has resulted in a portable demonstration unit. A trial system is to be evaluated in the coming year.

Dr. Thomas Jahns, who has been a Visiting Scientist and Lecturer in LEES has left to accept a tenured full professorship at the University of Wisconsin.

Dr. Thomas Keim has joined the LEES research staff as a Research Scientist and co-director with Prof. John Kassakian of the MIT Consortium on Advanced Automotive Electrical/Electronic Components and Systems.

Dr. Marija Ilic was elected to the grade of Fellow in the IEEE.

Professor Leeb was the recipient of the IEEE Power Electronics Society's 1999 Outstanding Young Power Electronics Engineer Award.

Prof. Zahn was the J.B. Whitehead Memorial Lecturer at the October 1998 Conference on Electrical Insulation and Dielectric Phenomena. He also received the 1999 Frank E. Perkins Award for Outstanding Advising of Graduate Students.

Graduate student Babak Ayazifar was awarded the Goodwin Medal, MIT's top teaching award for graduate students, and graduate students Christoforos Hadjicostis and Chalee Asavathiratham were selected for EECS Department teaching awards.

John Kassakian

MIT Reports to the President 1998-99