Dr. Hefner is an electronics engineer in the Applied Electrical Metrology Group in the Quantum Measurement Division of the Physical Measurement Laboratory (PML) at the National Institute of Standards and Technology (NIST). Dr. Hefner is a member of the NIST Smart Grid Team and is the Project leader for NIST's Power Devices and Thermal Measurements Project. He is specifically focused on advancing electrical interconnection standards and power conversion technologies necessary to enabel high penetration of renewable/clean energy sources, energy storage systems, and plug-in electric vehicles. He joined NIST, Gaithersburg MD in 1983 and has held several positions including Group Leader for Semiconductor Devices, Project Leader for Power Devices and Thermal Measurements, Project Leader for Integrated Sensor System-on-a-Chip, and Project Leader for Semiconductor Device Simulation and Technology Computer-Aided-Design.
Dr. Hefner is the author of 75 publications, holds one U.S. patent, and has received a number of best paper and technical achievement awards. In 1993 he received a U.S. Department of Commerce Silver Medal Award for his pioneering work in developing the theoretical foundation and understanding used for device optimization and circuit utilization of the Insulated Gate Bipolar Transistor (IGBT). In 1996, he received the NIST Applied Research Award for development of the IGBT model provided within the most widely used power circuit simulation programs. Recently, in 2008 he received an appreciation award from the U.S. Department of Energy, Assistant Secretary of Fossil Energy for contributions to high-megawatt power conversion technology for Clean Energy Systems, and in 2009 he received a NIST Bronze Medal Award for technical leadership in development and application of the first high-voltage, high-frequency Silicon-Carbide switch mode power conversion devices.
Dr. Hefner was elected as a Fellow of the IEEE in 2001 where he has been active in the Power Electronics Society, the Industry Applications Society, the Electron Devices Society, and the Power and Energy Society. He has served on a number of IEEE Technical and Conference Committees including serving as the Transactions Review Chairman for the IEEE Industry Applications Society Power Electronics Devices and Components Committee (1989–1997) and serving as the IEEE Electron Devices Society Standards Technical Committee Chairman (1996–2001). In 2005 he served as the Chairman of the International Semiconductor Device Research Symposium and he has served as a Steering Committee member for the Government Microcircuit Applications and Critical Technology Conference since 2006.
Dr. Hefner has served as the Chairman of the Interagency Advanced Power Group (IAPG), Electrical Systems Working Group (ESWG) since 2007 where he leads program coordination and information exchange among different federal government agencies in the area of electrical power conditioning. Dr. Hefner has also recently initiated and hosted several workshops at NIST on high-megawatt power conditioning systems including: the "High Megawatt Converter Workshop" held at NIST on January 24, 2007, the "High-Megawatt Converter Technology R&D Roadmap Workshop" held at NIST on April 8, 2008, the "NSF Workshop on Advanced Power Conditioning for Alternate Energy Systems" held at NIST on May 28-29, 2008, the "Workshop on Future Large CO2 Compression Systems" held at NIST on March 30-31, 2009, and the "Workshop on Challenges to Growth of Grid Connected Electronics" held at NIST on December 11, 2009.