20-kilowatt wireless car charging system closer to production image

Researchers have developed a wireless charging system that has 90 percent efficiency at three times the rate of the conventional electric car plug-in charging systems.

Charging infrastructure plays a crucial role in spurring the demand for electric cars and researchers are already looking for more efficient ways to expand the technology. A fast 20-kilowatt wireless charging system has been developed in the US by the government-backed Oak Ridge National Laboratory in partnership with Toyota, Cisco Systems, Evatran, and Clemson University International Center for Automotive Research. ORNL’s power electronics team achieved this world’s first 20-kilowatt wireless charging system for passenger cars in less than three years, an architecture that includes an ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies. For the demonstration, researchers integrated the single-converter system into an electric Toyota RAV4 fitted with an additional 10-kilowatt hour battery, with energy being transferred from a transmitting plate in the ground to a receiving plate underneath the car, from where it is then transferred to the battery.

“We have made tremendous progress from the lab proof-of-concept experiments a few years ago,” said Madhu Chinthavali, ORNL Power Electronics Team lead. “We now have a technology that is moving closer to being ready for the market.” ORNL said it was already looking ahead to its next target of 50-kilowatt wireless charging, which would match the power levels of commercially available plug-in quick chargers.