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Scientists Develop Wireless Charging for Electric Vehicles

James Cummings
11.02.16
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A new wireless technology that can charge electric vehicles has been developed.
Scientists at the US Department of Energy's Oak Ridge National Laboratory (ORNL), who developed the 20-kilowatt wireless charging system, say the technology has a 90% efficiency and operates at three times the rate of the conventional plug-in systems used for electric vehicles.

The wireless electric vehicle charging (WEVC) system uses a single-converter system, and to demonstrate its power and efficiency, the researchers integrated the technology into an electric Toyota RAV4 fitted with an extra 10-kilowatt hour battery. A transmitting plate was placed in the ground to transfer energy to a receiving device inserted in the SUV's front end. With that connectivity in place, energy was transmitted to the vehicle's battery through a controller.

The next stage of the wireless electric vehicle charging (WEVC) technology project is aiming for 50-kilowatt wireless charging target, which would match the energy transmission level of plug-in chargers the market. If this breakthrough is achieved, it would have significant impacts on the manufacture and use of electric vehicles, as well as create sufficient charging power for heavy vehicles like trucks and buses.

In April, Ricardo and Qualcomm Halo signed a Wireless Electric Vehicle Charging (WEVC) technology agreement, which grants Ricardo the license to engineer and supply the WEVC systems for auto makers, while Qualcomm provides technical and engineering support and expertise.

Under the partnership, Ricardo will produce wireless charging devices custom-made for autonomous vehicles, SUVs, taxis; in addition to making high-power, fast-charging systems and embedded inductive pads.

CEO of Ricardo, Dave Shemmans said the landmark agreement is in keeping with the company's philosophy of developing vehicle and transportation technologies that encourage low and zero emission.

How wireless charging works for electric cars

Electric car drivers traditionally use a plug-in system to recharge their vehicles, but the more advanced and more convenient technology of wireless charging eliminates the function of the cord.

Here's how it works:

Utilizing the principles of electromagnetism, the wireless-charging technology works by transmitting electric currents through a coil of wires to create a magnetic field. The generated electric power is then transferred between two coils with no physical connection.

The coils that activate the wireless electric-car charging are embedded, one, on a pad placed on the ground and underneath the front end of vehicle. The other coil is inserted in a receiver component mounted on the underside of the vehicle.

Earlier produced systems required that the charging pad is placed very close to the receiver, but Halo says that with its new Halo system vehicles can be wireless charged by from a distance of up to 250 millimeters or 10 inches of the pad. That certainly fixes one of the major concerns of electric vehicle (EV) users contemplating a wireless charger for their cars.

But since a wireless charging receiver needs to be embedded in vehicle, to make it commercially viable, automakers need to commit to engineering their EV models by installing the necessary equipment to make them compatible with the technology. But although vehicle manufactures like Volvo and Nissan have reviewed the technology, they are yet to commit to applying it to their production models.

However, at the recent Geneva Motor Show, Jochen Strenkert who heads the Mercedes hybrid-powertrain revealed that the automaker would install wireless technology in its 550e plug-in hybrid 2017 model.

The future of powering vehicles

Although the wireless charging technology is still in its teething stage, its potential for more convenient electric vehicle use and the huge prospects it holds have spawned even more ambition visions: Embedding wireless charging system on the road so vehicles can charge on the go.
Scientists and researchers at Qualcomm are already setting their sights on a grand future where with embedded wireless technology you can charge your car while driving, rather than when parked.
That would thrice raise the bars of comfort and convenience, but will also come at great costs. For example, building and fixing bridges will take priority over the extra expenses over embedded wireless charging chip below the road surface.

Industry regulations

Another concern of industry stakeholders is the issue of standardization, a factor that has slowed the commitment and manufacture of WEVC-compatible vehicles by top EV makers.
But in May, the Society of Automotive Engineers (SAE) released a set of industry guidelines for wireless power transfer (WPT) for automakers and original equipment manufacturers (OEMs). The guidelines set criteria for safety and electromagnetic limits, as well as minimum standards for efficiency and interoperability, in addition to a test setup for approval of WPT.

SAE has now specified four categories of WPT power levels, and added that future revisions may include higher levels.

Vehicle manufactures and OEMs have built J2954-compatible systems which use 3.7 kW electric power - the first of the SAE categorizations (WPT 1). The systems are currently being reviewed with the data result to be used to set a final standard by 2018.

The other three categorizations are TIR J2954, with specification of 7.7 kW (WPT 2), 11 kW (WPT 3) to be specified in revision of J295, and 22 kW (WPT 4) to be specified in revision of J2954.

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