Researchers from Oak Ridge National Laboratory developed a 120-kilowatt wireless charging system for vehicles
A team of researchers at the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) demonstrated a 120-kilowatt wireless charging system for vehicles. The charging system is capable of offering six times the power of previous ORNL technology. The wireless system can transfer 120 kilowatts of power with around 97% efficiency. In the laboratory demonstration, the charging system was used to transfer power across a six-inch air gap between two magnetic coils and the system also charged a battery pack.
The project that was demonstrated on October 19, 2018, was led by Veda Galigekere of ORNL’s Power Electronics and Electric Machinery Group. The team used finite element and circuit analyses to develop a new co-optimization methodology and improved the coil design and ensured that the system does not overheat or pose any safety issues. Moreover, the team made certain that any loss of power during the transfer was minimal. The 120 kilowatts system is equipped with the new coil design co-optimized with the latest silicon carbide power electronic devices for a lightweight and compact system. The system receives energy from the grid and converts it to high-frequency alternating current. This conversion generates a magnetic field that helps to transfer power across a large air gap. The energy is later transferred to the secondary coil, where it is converted back to direct current.
The demonstration closes to DOE’s extreme fast-charging goal of fabricating a system capable of offering 350 to 400 kilowatts with a reduced charging time of 15 minutes or less for electric vehicles. According to Moe Khaleel, associate laboratory director for Energy and Environmental Sciences at ORNL, the breakthrough advances the technology required to increase preference of electric vehicles. The ORNL team is focused on increasing power transfer level to 200 and eventually 350 kilowatts and refining dynamic wireless charging technology. A dynamic wireless charging technology allows automatic charging of electric vehicles through wireless charging pads installed under roadways. The research was funded by DOE’s Vehicle Technologies Office (VTO) and performed at the National Transportation Research Center, a DOE user facility at ORNL.