|Wireless charging with WiTricity. Click to enlarge.|
Delphi Automotive has reached an agreement with WiTricity Corp., a wireless energy transfer technology provider, to develop automatic wireless charging products for hybrid and electric vehicles. The collaboration between the two companies is intended to help establish a global infrastructure of safe and convenient charging options for consumer and commercial electric vehicles.
WiTricity is commercializing an approach to “mid-range” wireless charging—distances from a centimeter to several meters. (Earlier post.) Developed by a team led by MIT Professor Marin Soljačić, the company’s technology is based on sharply resonant strong coupling, and is able to transfer power efficiently even when the distances between the power source and capture device are several times the size of the devices themselves. WiTricity’s technology is a non-radiative mode of energy transfer, relying instead on the magnetic near field.
The power transfer efficiency of a WiTricity solution depends on the relative sizes of the power source and capture devices, and on the distance between the devices. Maximum efficiency is achieved when the devices are relatively close to one another, and can exceed 95%.
According to Eric Giler, CEO, WiTricity, its charging system can already transfer more than 3,300 watts—enough to fully charge an electric car at the same rate as most residential plug-in chargers. Drivers would simply park their electric vehicle over a wireless energy source that sits on the garage floor, or is embedded in a paved parking spot.
Delphi’s expertise in global engineering, validation and manufacturing coupled with WiTricity’s patented wireless energy transfer technology uniquely positions us to make wireless charging of electric vehicles a reality.—Randy Sumner, director, global hybrid vehicle development, Delphi Packard Electrical/Electronic Architecture
Delphi also makes a Portable Electric Vehicle Charger that fits in the trunk of an electric vehicle. The UL-listed charging system plugs into any standard 120-volt outlet to enable safe electric vehicle battery charging at home or away. The charging unit can also be integrated into stationary charging applications.
André Kurs, Aristeidis Karalis, Robert Moffatt, J. D. Joannopoulos, Peter Fisher, Marin Soljačić (2007) Wireless Power Transfer via Strongly Coupled Magnetic Resonances. Science Vol. 317. no. 5834, pp. 83 - 86 doi: 10.1126/science.1143254