Wireless charging certainly seems like the future, but the lack of technical standards has stalled the release of systems from the major EV makers. Now SAE has published an industry guideline for wireless power transfer (WPT) between infrastructure, vehicle suppliers and OEMs.
“SAE TIR J2954 Wireless Power Transfer for Light-Duty Plug-In/ Electric Vehicles and Alignment Methodology” defines criteria for safety and electromagnetic limits, efficiency and interoperability targets, as well as a test setup for the acceptance of WPT.
“Wireless power transfer using SAE TIR J2954 is a game changer for PH/EVs,” said Jesse Schneider, Chair of SAE’s Wireless Power Transfer Committee. “This will enable consumers to simply park their vehicles into spaces equipped with TIR J2954 equipment and walk away without doing anything to charge their PH/EV.”
“Standardization of both the vehicle and ground infrastructure WPT has started with SAE TIR J2954. The frequency band, safety, interoperability, EMC/ EMF limits as well as coil definitions from SAE TIR J2954 enable any compatible vehicle to charge wirelessly from its WPT home charger, work, or a shopping mall WPT charger, etc. with the same charging ability. All of this makes it possible to seamlessly transfer power over an air gap with high efficiencies.”
SAE TIR J2954 establishes a common frequency band using 85 kHz (81.39 – 90 kHz) for all light-duty vehicle systems. It also defines four classes of WPT power levels (future revisions may include even higher levels):
- 3.7 kW (WPT 1) specified in TIR J2954
- 7.7 kW (WPT 2) specified in TIR J2954
- 11 kW (WPT 3) to be specified in revision of J2954
- 22 kW (WPT 4) to be specified in revision of J2954
Automakers and suppliers have built J2954-compatible systems, which are currently being tested by a team from the DOE and the Idaho and Argonne National Labs. The test data will be used to finalize the standard by 2018.