POWER ELECTRONICS & ELECTRIC MACHINERY

Equipment and Capabilities

The MDF includes a wide array of fixed equipment to support Additive Manufacturing Metal Deposition.  This includes: 

  • 600-volt, 600-ampere bi-directional dc power supply
  • 100-hp, 10,000-rpm 4-quadrant dynamometer
  • 450-hp, 15,000-rpm water brake dynamometer
  • Ultra high-speed rotational equipment safety tank
  • Programmable environmental oven to 750°C
  • Environmental chamber with humidity control capability from −50 to 180°C
  • Environmental laboratory hood
  • WBG material and medium-voltage (up to approximately 1200 V) device evaluation facility including
    • device and component characterization at temperatures up to 600°C
    • static and dynamic measurements of diodes and switches up to 1,200 V and 400 A
    • testing of devices up to 30 V gate drive and down to 10 ns switching times
    • extraction of device capacitances up to 1000 V
    • dynamic reverse biasing test
    • leakage current measurement
    • avalanche testing
  • WBG high-voltage (up to 20 kV) device evaluation including
    • maximum voltage and current without transformer: 2.2 kV, 0–11A
    • rise time of 20 ns (to 2.2 kV), 15 ns (to 500 V); fall time: 35 ns
    • pulsewidth 0.05 ms to 1000 ms
    • pulse repetition rate single shot to 1 MHz
  • The PEEM Laboratory provides approximately 835 m2 (9,000 ft2) of space, including areas specifically designed for proprietary research.
  • Access to co-located facilities, including the Fuels, Engines, and Emissions Research Center, Vehicle Systems Integration Laboratory, Battery Manufacturing Facility, Center for Transportation Analysis, and Manufacturing Demonstration Facility
  • Access to ORNL’s world-class expertise and facilities for leadership computing, neutron imaging, and materials characterization.

PEEM researchers design and build novel components, such as this inverter, which features 3-D printed parts and WBG materials.

Electric, hybrid, and fuel cell vehicles need electric drive system components that are lightweight, compact, durable, and efficient. Oak Ridge National Laboratory’s Power Electronics and Electric Machinery (PEEM) group is focused on developing revolutionary new power electronics, electric motor, and traction drive system technologies that will leapfrog current on-the-road technologies, leading to lower cost and better performance.

The PEEM Laboratory is a primary laboratory for DOE Vehicle Technologies Office electric drive technologies research and development. Current projects include benchmarking industry devices, developing new technologies for thermal management and packaging of power electronics, prototyping novel power electronics components, creating wireless charging systems for electric vehicles, extending power module operating range with wide bandgap materials, and designing new motors and digital controls that reduce or eliminate the use of rare earth materials. PEEM researchers use analysis, modeling, simulation, and unique, PEEM-developed equipment and capabilities to evaluate power electronics and electric machines.

Projects are funded primarily through the DOE Electric Drive Technologies program, with additional funding from the Advanced Research Projects Agency-Energy (ARPA-E) and industry partners. Researchers also work closely with industry through organizations such as U.S. DRIVE, which bring together government and automotive manufacturers.

PEEM staff members hold advanced degrees in physics and electrical and mechanical engineering. Collectively, they have been granted more than 50 patents and published more than 400 technical papers. Most are active members of professional societies such as the Institute of Electrical and Electronics Engineers, the Institution of Electrical Engineers, the American Society of Mechanical Engineers, and the Society of Automotive Engineers, and hold leadership positions in these organizations.

Building Better Components

Researchers are focused on developing lighter, smaller, more rugged, and more efficient components to control the flow of power in the electric vehicle drivetrain (e.g. chargers, inverters, and dc-dc converters). Using all–silicon carbide (SiC) semiconductors, PEEM staff are targeting reductions in onboard charger and dc-dc converter costs of 50% while maintaining efficiency and cutting component weight and volume in half.

PEEM engineers have developed all–silicon carbide (SiC) inverters with innovative high-temperature module and heat sink designs. For example, researchers leveraged ORNL capabilities in additive manufacturing to create a novel liquid-cooled all-SiC traction drive inverter, featuring 50% printed parts. The inverter has an optimized, 3-D printed heat sink, which allows for better heat transfer throughout the unit. Through additive manufacturing, researchers were able to place lower-temperature components close to the high-temperature devices, further decreasing the electrical losses and reducing the volume and mass of the package.

Wide Bandgap (WBG) Power Devices

Researcher Madhu Chintahavali works with PEEM's unique wide bandgap device evaluation equipment.

WBG technology enables devices to perform more efficiently at a greater range of temperatures than conventional semiconductor materials. Specific advantages of WBG devices include: higher inherent reliability; higher overall efficiency; higher frequency operation; higher temperature capability and tolerance; lighter weight, enabling more compact systems; and higher power density.

ORNL collaborated with partners to build the industry’s first silicon insulated-gate bipolar transistor–SiC Schottky diode hybrid 55 kW inverter. The WBG SiC materials enable the inverter to perform with up to 30% efficiency improvement compared to an all-silicon module.

WBG device evaluation has been performed by ORNL in the WBG Data Analysis and Technology Assessment (DATA) facility for more than 10 years. Benchmarking evaluation and characterization are done at the bare die and packaging level and through device modeling. ORNL works collaboratively with device manufacturers from around the world to assist in moving WBG device technology forward.

Packaging

In the power device packaging laboratory, researchers are engaged in the development of advanced power electronics modules for electric vehicles. Research and development is targeted to achieve comprehensive improvements in efficiency, functionality, reliability and cost effectiveness of power electronics modules.

PEEM advances the electrical, thermal, and thermo-mechanical performance of power modules through structural optimization, materials development, and innovations in manufacturability. Current projects are focused on developing novel power packaging techniques that exploit the superior attributes of WBG semiconductor materials.

For example, researchers created a highly integrated power module package that features double-sided cooling and three-dimensional, planar power interconnection. These new packaging technologies have been demonstrated in the fabrication of all-SiC power modules that show improvements in efficiency, power density, system cost savings, and ease of manufacturability.

Wireless Charging

PEEM has developed wireless charging technology that works with the same speed and efficiency as plug-in charging.

ORNL has developed wireless charging technology that can charge an electric vehicle (EV) battery with the same speed and efficiency as standard plug-in charging. Charging coils on the ground transfer energy across a 16 cm air gap to the coils attached to the underside of the vehicle. This inductive charging process uses a magnetic field that emits less radiation than a laptop computer. ORNL has demonstrated this technology by retrofitting a Toyota Prius with charging coils.

Researchers have also demonstrated dynamic wireless charging using a small GEM vehicle. Wireless charging while in motion over electrified roadways would enable drivers to charge their vehicles on their daily commutes, expand EV range, and allow fuel economy gains through downsizing of EV batteries.

Electric Machines

Researchers are developing novel concepts and building new electric motors that reduce or eliminate the use of rare earth materials while maintaining high power density, specific power, and efficiency. Most electric and hybrid electric vehicles on the road today have motors that use rare earth permanent magnets. The US currently imports rare earth materials, so researchers are focusing on this area as a matter of national energy security.

The PEEM group uses sophisticated computer simulation to identify new motor designs that meet the performance parameters without employing rare earth materials. Researchers build the most promising prototypes and evaluate the motors using dynamometers and other testing capabilities.

Oak Ridge National Laboratory is managed by UT-Battelle for the Department of Energy