The grid-connected 20-kilowatt bi-directional wireless charging system was tested on a UPS delivery truck, transferring power from a charging pad over an 11-inch gap using two electromagnetic coupling coils at more than 92 percent efficiency.

The setup comprises the lab's custom coil design and control system, and wide bandgap power conversion systems. It draws from the grid and converts energy to direct current voltage, before a high-frequency inverter switches that to alternating current. A magnetic field is subsequently created and this sends power over the gap where it's converted back to direct current to charge the truck's 60-kWh batteries.

The research team notes that where it might take up to six hours to charge the vehicle's battery over a conventional wired charging setup, the wireless charging system could do so in around three hours.

Since it's a bi-directional system, the truck's batteries could be used to store energy from on-site renewables like solar panels or wind turbines. Technical team lead on the project, Omer Onar, reckons that scaling up the technology to a 50 truck fleet could give operators megawatt-scale energy storage options.