ORNL’s Omer Onar, left, power electronics research lead, discusses the 270-kW wireless charging system’s lightweight polyphase electromagnetic coupling coil, pictured in foreground, with Lee Slezak, center, DOE’s Vehicle Technologies Office technology manager for grid and charging infrastructures. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy
The achievement surpasses ORNL’s recent 100-kW wireless charging demonstration and is another breakthrough for fast wireless charging.
“In the past three months, the ORNL vehicle power electronics and electric drives research teams have set impressive world records for wireless charging," said Lee Slezak, DOE’s Vehicle Technologies Office technology manager for grid and charging infrastructures. “These achievements will further speed up the adoption of electric vehicles in the U.S.”
As a light-duty passenger vehicle, the Porsche Taycan would be difficult to equip using conventional large, heavy wireless power transfer systems. The vehicle can’t support the charging hardware due to space, weight and volume limitations. Existing wireless charging systems for light-duty vehicles are currently under development for up to 11-kW power levels with up to 92% efficiency. Current industry standards cover up to 20-kW power levels.
The ORNL-invented system that transferred power to the Porsche uses lightweight polyphase electromagnetic coupling coils with a diameter just over 19 inches that allow for higher power density in the smallest coil possible. This process is similar to the wireless charging of small consumer devices, but the unique geometry and design of the polyphase coils enable the transfer of extremely high power levels using rotating magnetic fields generated by the coil phase windings to boost the power. The charging system was seamlessly integrated into the undercarriage of the vehicle.
The wireless power transfer technology also includes protection systems that prevent exceeding voltage and current limits, overheating and short-circuiting. These systems can initiate shutdown procedures in the event of power interruptions or other unexpected conditions that would interfere with safe power transfer.