GOOGLE appears to be developing wireless charging for its electric self-driving cars.
Documents filed at the US Federal Communications Commission (FCC) suggest that Google is working toward beaming power to them instead of relying on plug–ins, the spectrum.ieee website is reporting.
The filings reveal that Google has been testing two wireless charging systems for its prototype electric self-driving cars in California.
Google is employing the services of two other companies, Hevo Power from New York City and Momentum Dynamics from Philadelphia.
Both companies use the same principle to send electric energy through the air, relying on a transmitter embedded in the ground and a receiver mounted on the underside of an electric vehicle.
The principle is called resonant magnetic induction and functions by creating an oscillating magnetic field with the help of an alternating current passing through a tuned electrical circuit. In turn, that magnetic field induces another alternating current in the circuit mounted on the vehicle, enabling it to recharge the onboard battery.
Hevo’s installation at the Googleplex involved a prototype charger, called Alpha, that can deliver 1.5 kilowatts of power from a circular transmitter “embedded like a manhole cover” in pavement. Momentum Dynamics claims that it has developed wireless transmitters with power ratings of up to 200 kW — although the FCC filings did not disclose the specifications of the system Google is using.
Wireless charging will be essential if Google’s vehicles are to realise the vision of Chris Urmson, director of its self-driving car program.
“We’ve heard countless stories from people who need a fully self-driving car today,” he wrote in December. “We’ve heard from people with health conditions ranging from vision problems to multiple sclerosis to autism to epilepsy who are frustrated with their dependence on others for even simple errands.”
The idea is that, initially, a self-driving car would position itself briefly over a charging pad between rides, and ultimately, the infrastructure would be put in place that would allow a car to continually recharge its batteries as it travels along the road.
This could allow carmakers to use smaller, lighter batteries than those required for today’s electric vehicles, which carry all their energy on board. In addition to dramatically reducing an EV’s weight and offering design freedom, it would slash the price of the electric car’s most expensive component. Daga says that Momentum’s high-power chargers can already recharge electric bus batteries in a matter of minutes, allowing them to be in service virtually 24 hours a day.
Momentum Dynamics and Hevo Power declined to confirm any involvement with Google, and Google itself noted only that it tests many different technologies for its self-driving vehicles. All the prototype cars currently being tested in public are recharged using traditional conductive charging cables.
The world electric single seater car championship, Formula E, is already experimenting with wireless charging.
This season, its safety car, a BMW i8, has been outfitted with Qualcomm’s Halo 7.2kW wireless charging system, said to be able to charge the vehicle’s batteries in one hour.
Qualcomm says that the new charging system delivers twice as much energy to the safety car’s batteries as last year’s 3.6kW system. This reduces the charging time by half, with a full charge possible in as little as one hour.
Charging is done via the Qualcomm Halo DD technology in which a vehiicle is parked over a charging pad that transfers energy through the air to another aligned pad on the bottom side of the car.