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.
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.
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 and UL signed an MoU to jointly develop and share WPT standards to help accelerate certification of wireless power transfer for electric vehicles.