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Power Device and Thermal Metrology


The Power Devices and Thermal Metrology Project develops electrical and thermal measurement methods and equipment to support development and application of advanced power semiconductor devices and ICs. The Project performs research enabling integration of advanced power electronics technologies into future energy systems, and supports development of Smart Grid measurement methods and standards for Distributed Generators, Renewables and Storage.


Switch-mode power conversion using power semiconductor devices provides the means to convert electricity from one voltage to another, to convert between direct current (DC) and alternating current (AC), to condition power waveforms to meet device and system needs, and to control motion by modulating electric power to motor windings or mechanical actuators. As power semiconductor technology has evolved over the last few decades, from slow low-voltage low-power devices to today's fast high-voltage high-power devices, switch mode power conversion has become pervasive and essential in electrical and electronic systems.

NIST provided the theoretical foundation and measurement methods that aided development and rapid adoption of the most widely used high power semiconductor device known as the Insulated Gate Bipolar Transistor (IGBT). As the IGBT began to reach its fundamental limits at high voltage, NIST work transitioned to devices made with new wide-band-gap semiconductor materials such as Silicon-Carbide (SiC) that are beginning to replace conventional power devices made with Silicon. Power semiconductor devices made with SiC enable operation at higher voltages, higher speeds, and higher temperatures. NIST work focuses on measurements, modeling and analysis that enables industry to more rapidly integrate advanced power semiconductor device, package, and cooling system technologies into a wide range of applications.

Advanced power electronics technologies are becoming critically important to meet the nation's energy and defense priorities such as energy independence, increased capacity and stability/resiliency of the power grid, renewable/clean power generation, electric transportation, and electrification of DOD platforms and systems. For example, power conditioning systems (PCSs) are required to convert low voltage unregulated power produced by renewable/clean energy sources, such as photovoltaic solar or wind, to high voltage power synchronized with the grid. NIST is leading efforts to coordinate industry and other federal agency programs to reduce cost and improve performance of these high-megawatt PCSs. PCSs are also required to charge plug-in electric vehicle batteries, and to deliver power waveforms to the windings of the electric propulsion motor. NIST is developing electro-thermal-network component models and measurement methods to support rapid adoption of advanced electric vehicle propulsion system technologies.

As electrification of energy systems has become pervasive, information network technology has become a key enabler for advancement of mobile and stationary power systems. Recently, the Energy Independence and Security Act of 2007 assigned NIST "the primary responsibility to coordinate development of a framework that includes protocols and model standards for information management to achieve interoperability of smart grid devices and systems…" To meet this responsibility NIST established the Smart Grid Interoperability Panel (SGIP) as a forum to coordinate the many stakeholders and standards development organizations (SDOs) involved in Smart Grid.

The Power Device and Thermal Metrology Project initiated and leads the SGIP Distributed Renewables, Generators, and Storage Domain Expert Working Group as well as two SGIP priority action plans; one for distributed generator interconnection and object models standards, and another for wind plant communication standards. These efforts have played an important role in coordinating distributed generator operators, utilities, standards development organizations, and federal and state regulatory commissions in advancing distributed generator functionalities such as voltage regulation and voltage/frequency ride through that will provide better grid stability and resiliency while also increasing the value propositions of renewable generators. This Project is also playing a major role in developing the new NIST Smart Grid Interoperability Test Facility focused on microgrid PCS devices that provide both grid-facing and customer-facing functionalities such as the ability to isolate from disturbances and to operate independently during grid outages.

Major Accomplishments:

  • NIST experimentally validated models used to design first 4.5 kV Si IGBT/SiC JBS hybrid module and used to design Naval electric ship power converters using these modules
  • NIST unique high-voltage high-frequency power switching tester demonstrated fast switching capability of first 12 kV SiC n-IGBTs and 15 kV SiC p-IGBTs.
  • NIST Leading Interagency Advanced Power Group (IAPG), Electrical Systems Working Group (ESWG) that coordinates Army, Navy, Air Force, NASA, DOE and NIST programs on microgrids and wide bandgap power devices
  • NIST lead SGIP Priority Action Plan and Domain Expert Working Group coordinated development of recommended practices, standards, test method, and regulatory procedures for distributed generator interconnection including voltage regulation and voltage/frequency ride through
  • NIST Electro-thermal-mechanical models developed and experimentally validated to demonstrate safe operation and reliability of double-sided cooling IGBT modules for electric vehicle propulsion inverter  
Allen Hefner, Jr., of the Power Device and Thermal Metrology Project
Hefner developing world-class High Voltage, High Frequency Power Transistor Switching Tester. (Copyright Robert Rathe)

End Date:


Lead Organizational Unit:



Allen Hefner, Leader
Colleen Hood

Allen R. Hefner, Jr.
301-975-2071 Telephone
100 Bureau Drive, M/S 8120
Gaithersburg, MD 20899-8120