SAE International publishes TIR J2954/2 for wireless charging of heavy-duty EVs; static and dynamic WPT
SAE International has published the first Technical Information Report (TIR) that specifies, in a single document, both the electric vehicle- and ground-system requirements for heavy-duty (HD) wireless charging of electric vehicles (EV).
SAE TIR J2954/2 Wireless Power Transfer & Alignment for Heavy Duty Applications helps pave the way for charging HD vehicles without the need for plugging in—widely considered to be a key enabler for accelerating the adoption of EVs and autonomous vehicles. The new guideline builds off the success of the first light-duty SAE J2954 standard published in 2020. The SAE TIR J2954/2 exponentially increases the power level of Wireless Power Transfer (WPT) for heavy duty vehicles to 500 kW.
Charging a heavy-duty EV should be as simple as parking in the right spot—the wireless charging SAE TIR J2954/2 Guideline makes it possible to do that automatically.—Jesse Schneider, chair of the SAE Wireless Power Transfer Task Force (ZEV Station)
Power is transferred by creating a magnetic resonance field between the ground transmitting assembly and a vehicle assembly fitted on the underbody of a HD vehicle. The energy crosses an air gap (the ground clearance between the pads) and is then converted from AC into DC on the vehicle to charge the vehicle batteries.
The technology is a safe and efficient method for transferring power from the AC grid supply to the HD EV. Field trials using a 10-in. (250-mm) ground clearance has shown that WPT systems operate at grid-to-battery efficiencies of 92+%. WPT with additional alignment elements in SAE J2954/2 also offers the potential to fulfill the charging requirements for autonomous EVs to charge themselves without human interaction.
The SAE TIR J2954/2 is a game-changer guideline enabling ultra-fast wireless charging to 500kW, for both trucks and buses. It also makes it possible for wireless opportunity charging at stops for buses to overnight charging without a cord and HD truck sleeper cabs. To top it off SAE J2954/2 enables dynamic wireless power transfer, making it possible to charge while driving at roadway speeds. This enables a leap forward for wireless charging for EV heavy duty vehicles by establishing a common vehicle and parking location and frequency.—Jesse Schneider
SAE TIR J2954/2 Heavy-Duty Wireless Power Transfer has the potential to change the mindset of the fleet operators enabling both transit buses and truck fleets to go electric. It makes the whole prospect of charging easier to handle compared to conductive charging.—Mike Masquelier, subteam co-chair J2954 HD WPT (WAVE)
The TIR J2954/2 is a first big step for wireless HD dynamic charging. On-the-go charging will significantly reduce vehicle battery cost, weight and provide a flexible resource to electric utilities.—Dr. Regan Zane, subteam co-chair dynamic charging (Utah State)
Dynamic charging Kenworth at Utah State Test Track
Additionally, SAE J2954 published an updated version 2 of its SAE J2954 light-duty standard for wireless power transfer for electric vehicles. This update improves the standard by creating requirements to assist UL 2750 in creating a certification program for SAE J2954 light-duty systems.
SAE J2954 functional diagram
The SAE J2954 Standard has the potential to greatly accelerate validation and therefore commercialization of wireless charging systems for light duty vehicles.—Jesse Schneider, Chair SAE WPT Taskforce
SAE and UL signed an MoU to jointly develop and share WPT standards to help accelerate certification of wireless power transfer for electric vehicles.