In December 2016, interoperability between the so-called Double D (DD) and Circular Topologies was demonstrated between 3.7 to 7.7 kW (WPT 1 and WPT 2 power levels) with efficiencies exceeding 85-90% under aligned conditions. (Earlier post.)

The SAE J2954 task force is using 802.11n currently, which is similar to DSRC (IEEE 802.11p) (earlier post). The use of this communications methodology, which is used in vehicle-to-infrastructure communications (in this case vehicle wireless charging assembly), is basically interconnecting wireless charging with the new connected vehicles environment. For example, your nav system can lead you to a wireless charging point, J2954 would position your car, and payment would be automatic. Click to enlarge.

The Recommended Practice SAE J2954 will also contain guidance for vehicle alignment methods and determine a common location for the wireless charging ground assembly. Currently, magnetic field alignment through triangulation using the existing coils and alignment using an auxiliary antenna are being evaluated for this decision.

The goal is to provide one methodology to align in order to be able to charge with high efficiency all SAE J2954 stations. This is for both manual (self-parking) and autonomous (automated) alignment possibilities. It is important to know that the only way to charge an autonomous vehicle automatically is to use wireless charging and SAE J2954 Recommended Practice will standardize this.

—Jesse Schneider

Further, SAE International has made a proposal to Electrify America to start a build-out of multiple hundreds of Light Duty Wireless Chargers starting in 2019 in public locations in California and ZEV states in three stages. The first stage, for light duty vehicles, creates an infrastructure based on J2954 (for example in malls, large workplaces, condominium complexes, etc). SAE also proposes 100 Heavy Duty Chargers in 2020 based on SAE J2954/2 (for example public transit agency, truck stops for anti-idling, etc.) in 2021 to create a wireless charging infrastructure with alignment communications for autonomous vehicles (for example, taxi fleets).

This will also help independent organizations or government organizations to quantify how much wireless charging may increase the eVMT (electric Vehicle Miles Traveled) for wireless charging (inductive charging) vs. plug-in (conductive charging) electric vehicles. This could also be quantified in the form of a CO₂ reduction potential by implementing wireless charging both in the home and in public locations.

In addition, this could also provide some data to help to understand the potential of wireless charging to reduce the pulse in criteria pollutants emitted with the engine cold start of a range extender engine. (The last, noted Ryan Hart from the California Air Resources Board (ARB) in his talk at the SAE symposium, is not a negligible problem.)

With a coordinated preliminary rollout of this technology, statistical information to gauge customer acceptance of both this new charging methodology as well as increased acceptance of the electric vehicle (for instance with convenience less or no range anxiety using wireless charging) can be gauged.

Additionally, the heavy-duty wireless charging standardization initiative SAE J2954/2 is kicking off on 10 February in San Diego following the SAE symposium to standardize wireless power transfer at 50 kW-250 kW. This is to address opportunity charging at bus stops (similar to the Scania testing in Sweden, (earlier post).

Pictures courtesy of Condutix Wämpfler, Scania, and WAVE technologies. Click to enlarge.

In addition, the meeting will launch an investigation of the optimized wireless charging power level to offset idling for HD trucks at truckstops (and address the anti-idling laws).