SAE International finalizes light duty wireless charging standard to enable mass commercialization

SAE International published SAE Standard J2954, Wireless Power Transfer (WPT) for Light-Duty Plug-in/Electric Vehicles and Alignment Methodology. The SAE Wireless Power Transfer Task Force has completed a lengthy consensus process finalizing the wireless charging specification with the vehicle to WPT pad alignment. The so-called Differential Inductive Positioning System (DIPS) was the technology alignment methodology for the SAE J2954 standard. The taskforce, consisting of automakers (OEMs), Tier 1s, and wireless charging suppliers, were surveyed to determine minimum common methods for alignment (fine alignment, pairing, and alignment check) to be standardized and agreed upon DIPS as the alignment technology for the newly published SAE J2954 Standard.

“The next generation of EV charging can be as simple as parking in a spot, with automatic J2954 wireless charging,” states Jesse Schneider (ZEV Station), chair of the SAE WPT Task Force. “The SAE WPT Taskforce has extensively tested wireless power transfer and alignment in the lab and the field allowing safe wireless power transfer up to 11kW with efficiencies to 93%. Now, the new standard gives consistent alignment in an exact parking spot with the DIPS System. This will enable seamless wireless charging & parking even for autonomous vehicles in the rain and snow. With the J2954 standard, the team has solved the missing link, enabling the start of commercialization of wireless charging for EVs, a gamechanger.”

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One innovative feature of the DIPS is that the vehicle assembly seamlessly recognizes multiple ground assemblies, pairs automatically, and enables precise alignment, even in all-weather conditions. “With the great teamwork of the SAE Wireless Power Taskforce together with the DIPS-Team, wireless charging with SAE J2954 Standard has become the first standardized automatic charging technology. This step marks a significant breakthrough towards achieving scalability and mass production of wireless charging systems,” states Dr. Mike Böttigheimer (MAHLE, Member of SAE J2954 Taskforce).

“The EV market has matured with conductive charging. By publishing SAE J2954 standard, the next models of light duty EV vehicles can reap the benefits of automated wireless charging with alignment," states Dr. Andreas Wendt, co-chair of the Dynamic Power Transfer subteam and director of Electreon Germany GmbH. "What is coming next, is dynamic wireless power transfer, where DIPS could play a similar role in alignment. With this disruptive technology, electric vehicles could charge while in motion. The SAE J2954 Team is testing this for the now for the upcoming SAE J2954/3 Recommended Practice."

The new J2954 standard alignment system, DIPS, is described as a low-intensity magnetic field generated from the ground assembly with multiple coils that can evaluated by the vehicle assembly for positioning. A conformance test is done to ensure interoperability between vehicle and charging pad. Ground and Vehicle WPT assembly manufacturers can develop and test their systems according to this interoperability specification. The DIPS transmitter and receiver coils can be fully integrated into the GA and VA.

Wireless Power Transfer (WPT) follows the SAE J2954 fully automatic wireless charging solution for electric vehicles and promises highly efficient charging (up to 93%) of electric and plug-in-hybrid vehicles. The missing piece of standardization of light duty WPT has been finding an alignment methodology which works in all weather conditions and environments and is interoperable between many different types of applications. This revision of SAE J2954 with DIPS enables automated parking and charging also for autonomous vehicles. The SAE WPT taskforce is also specifying high power wireless charging for heavy duty vehicles up to 500kW for its upcoming recommended practice SAE J2954/2.