ORNL 20kW wireless charging system hits 90% efficiency

Oak Ridge National Laboratory (ORNL) has been working on a wireless charging system for EVs and plug-in hybrids for years. The goal is to create a system that makes charging EVs and hybrids easier for drivers and to make EVs and other plug-in vehicles as cheap and easy to own as a gasoline vehicle. ORNL has announced that it has demonstrated a 20-kilowatt wireless charging system that has achieved 90% efficiency at three times the rate of the plug-in systems commonly used in electric cars today.

ORNL has multiple industry partners that are participating in this program including Toyota, Cisco Systems, Evatran, and Clemson University International Center for Automotive Research. "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 have set a path forward that started with solid engineering, design, scale-up and integration into several Toyota vehicles. We now have a technology that is moving closer to being ready for the market."

The wireless charging system includes ORNL-built inverter, isolation transformer, vehicle-side electronics and coupling technologies, and it was built in under three years. The demonstrator system is integrated into a Toyota RAV4 with a 10kW battery. The next goal for the researchers is to create a 50kW wireless charging system that can match the power of commercially available quick plug-in chargers. These higher power-charging systems are essential for charging larger electrified vehicles like buses and trucks.

"Wireless power transfer is a paradigm shift in electric vehicle charging that offers the consumer an autonomous, safe, efficient and convenient option to plug-in charging," said David Smith, vehicle systems program manager. "The technology demonstrated today is a stepping stone toward electrified roadways where vehicles could charge on the go."