Startup considers how to recharge electric vehicles wirelessly

MALVERN, Pa. — Imagine a world in which a vehicle is refueled automatically — hands free, no credit-card swiping, a completely background transaction.

Andy Daga envisions such a world. Daga, 61, is chief executive of Momentum Dynamics Corp., a tech company in Malvern, near Philadelphia, that has developed a wireless recharging system for electric vehicles (EVs) in which energy is transferred from a panel embedded in the pavement, through the air, into an EV.

Daga says the system is similar to a wireless recharger for a cellphone, though it transfers energy in far bigger volumes. He believes wireless recharging will extend the distances electric vehicles can travel, helping to overcome “range anxiety” about battery limitations that has hindered widespread consumer adoption of EVs.

“This is really revolutionary, to automatically operate fast-charging systems that nobody needs to interact with,” Daga said. “Your vehicle will automatically charge itself without thinking about it.”

Until the company can develop a network of wireless chargers embedded into parking lots and roadways, Momentum Dynamics is focused on serving a market of large electric vehicles such as municipal buses that follow a circuit and return repeatedly to the same location, where they get a quick charge, like a marathon runner taking gulps of water mid-race.

“We make incremental charges along the way,” Daga said. “That bus can then have unlimited range.”

Not everyone shares Daga’s conviction that wireless charging is the technology that will give EVs the market breakthrough the industry desires. About 100,000 batteryelectric vehicles were sold in the United States last year, less than 1 percent of the market.

“Wireless charging isn’t as efficient as battery swapping or a corded solution,” said Scott Shepard, a senior energy research analyst with Navigant Research.

Daga disagrees, and says wireless charging represents a cost-competitive solution, particularly in markets for buses, industrial vehicles such as forklifts, or short-haul trucks in ports.

Momentum Dynamics installed a new wireless charger recently at a Link Transit municipal bus terminal in Wenatchee, Washington, where it provides five-minute charges to an electric bus before it departs on its next scheduled circuit. The company launched a charging system last year at the Regional Transit Authority in Howard County, Maryland, in suburban Baltimore, and is currently installing a device in Chattanooga, Tennessee.

Without the enroute wireless charges, Wenatchee’s electric bus would run out of juice before the end of the day, said Todd Daniel, the agency’s maintenance and technology manager. The wireless charger means the bus can stay in service for a full 16-hour day.

Daniel said the recharging process is invisible to passengers. “You don’t know anything is different when this bus pulls over on a pad,” he said. “Passengers are getting on and off and nobody has a clue it’s getting charged.”

To a wired world accustomed to copper cables, wireless energy transfer seems magical. Conventional AC electrical current is converted into magnetic waves in a pad embedded into the pavement. A receiver mounted on the vehicle’s undercarriage turns the magnetic energy into DC electric current that is stored in the vehicle’s battery. MD’s system is designed to operate with an air gap of about 12 inches.

“It’s hard for the public to believe that,” Daniel said. “They can’t believe we’re transferring electricity through a magnetic field into the bus with no connection. It just blows people’s minds.”

Momentum Dynamics, which Daga calls “a Silicon Valley startup in the suburbs of Philadelphia,” was formed in 2009 and now employs 28 people, mostly engineers, in a crowded Malvern warehouse.

MD’s offices have the appearance of a garage workshop with intensely focused engineers huddled around computers, oscilloscopes and exposed circuit panels. Its quest is to increase the power throughput for the next generation of charging systems, while reducing weight, size and cost of the equipment.

The Wenatchee bus system is the first deployment of a 200-kilowatt system — about four times more powerful than MD’s previous system, and an industry milestone. Greater wattage delivers more power to vehicles more quickly, a critical factor to a transit system that needs to turn around buses rapidly. Daniel said the MD system adds about 16 miles of range to an electric bus in a five-minute charge.

The transmitter and receiver are matched to the same magnetic frequency, so energy losses are minimal and the system operates at 95 percent efficiency, Daga said, comparable to a plug-in charger.

Daga said the system is safe, and MD’s publicity video includes a person holding a working iPhone sandwiched between the magnetic panels. “We’re showing it’s safe,” Daga said. “It doesn’t give you any tingle. It doesn’t give you any heat. It doesn’t cause any damage to yourself or your phone.”