New inverter for lighter, more powerful electric vehicles

Researchers, including one of Indian-origin, have created a power inverter that could make electric vehicles lighter, more powerful and more efficient.
Power inverters convert direct current into the alternating current that powers the vehicle.
The new inverter, developed by researchers at the US Department of Energy's Oak Ridge National Laboratory, achieves much higher power density with a significant reduction in weight and volume.
At the core of this development is wide bandgap material made of silicon carbide with qualities superior to standard semiconductor materials, researchers said.
"Wide bandgap technology enables devices to perform more efficiently at a greater range of temperatures than conventional semiconductor materials," said ORNL's Madhu Chinthavali, who led the Power Electronics and Electric Machinery Group on this project.

"This is especially useful in a power inverter, which is the heart of an electric vehicle," Chinthavali said.

Specific advantages of wide bandgap 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.
Additive manufacturing helped researchers explore complex geometries, increase power densities, and reduce weight and waste while building ORNL's 30-kilowatt prototype inverter.
Using additive manufacturing, researchers optimised the inverter's heat sink, allowing for better heat transfer throughout the unit.
This construction technique allowed them to place lower-temperature components close to the high-temperature devices, further reducing the electrical losses and reducing the volume and mass of the package.

The research group's first prototype, a liquid-cooled all-silicon carbide traction drive inverter, features 50 per cent printed parts.
Initial evaluations confirmed an efficiency of nearly 99 per cent, setting the stage for building an inverter using entirely additive manufacturing techniques.
Building on the success of this prototype, researchers are working on an inverter with an even greater percentage of 3-D printed parts that's half the size of inverters in commercially available vehicles.