USU invention powers electric motors without wires
Logan • Batteries are the key challenge to developing practical electric vehicles, which have the potential to dramatically cut greenhouse emissions and U.S. dependence on oil. To store enough juice to enable a car to function the way Americans expect, batteries have to be big and expensive.
Utah State University electrical engineers have made a technical breakthrough that could solve this power-storage pitfall not by improving batteries, but by recharging them wirelessly, according to Jeff Muhs, director of USU's Energy Dynamics Laboratory (EDL) in North Logan.
EDL researchers have built prototype equipment that allows electricity to hop over a 10-inch span with 90 percent efficiency.
"This demonstration is an extraordinary and historic step in providing technologies to electric-vehicle owners who will be able to pull their cars into garages at home and charge without having to plug in with cords," Muhs said. "This is just the beginning."
The demonstrated efficiency compares favorably with the amount of electricity leaking out of the existing grid or lost from wall outlets, said Hunter Wu, a young EDL engineer leading the project.
"There are many challenges. We're making breakthroughs on energy conversion," said Wu during a recent demonstration. "Here we are going from direct current to high-frequency alternating energy, which creates the high-frequency magnetic fields to transfer power."
Wu, who was born in China and grew up New Zealand, came to the lab last year from the University of Auckland, where he was a scientific prodigy. Studying under a bioengineer who developed groundbreaking technology to wirelessly power heart implants, he earned a doctorate in electrical engineering at 19.
His team, which includes engineers Ky Sealy and Aaron Gilchrist, can move five kilowatts of electricity noiselessly from one interface across an air gap to a receiving pad, which powers a bank of light bulbs.
The USU Research Foundation, which oversees the EDL, is already on-track to commercialize the technology, which it hopes to protect with pending and provisional patents. Public transportation and off-road industrial equipment, such as forklifts, would be the first applications.
The first U.S. demonstration project for wireless power transfer in buses could be a University of Utah shuttle bus, according to Wesley Smith, a USU business development official who is leaving the university to head the company that will commercialize the technology.
Muhs has tooled EDL toward projects with "transformational" potential those that could reinvent the way U.S. society uses energy. Creating commercially viable ways to electrify roadways and grow algae as a biofuel stock are two ongoing efforts.
In another example, Muhs shrugs off the idea of improving light bulbs in favor of developing sensing equipment that determines where and when illumination is needed in buildings and automatically adjusting it for maximum efficiency.
Wireless power transfer is EDL's first technology to be launched into the real world. It "represents the disruptive technology that will eventually enable the safe and efficient electrification of highways," Muhs said. He hopes to develop the technology so that it can power automobiles as they speed down the road.
To get the wheels rolling, the university has spun off a company called Wireless Advanced Vehicle Electrification Technologies, or WAVE, one of numerous clever acronyms associated with the research foundation, itself called USURF.
Smith is setting up shop in downtown Salt Lake City, where he plans to develop demonstration projects to sell the idea to public-transit systems. He is already in talks with Las Vegas and Monterey, Calif., which are interested in WAVE's assistance to electrify bus routes.
The company's prospects are boosted by a California mandate that transit systems electrically power 20 percent of their bus fleets. Such buses cost three times that of their diesel counterparts. But wireless power transfer can reduce battery-capacity requirements by 90 percent, substantially lowering the costs of building and operating electric buses, Smith said.
His university-owned company envisions installing charging pads along routes so that buses replenish their batteries while stopping to serve passengers.
"It doesn't have to be a central location, but at any bus stop," Smith said. "The driver doesn't have to get out and plug anything in. He just has to drive over the pad. The beauty of the system is there are no moving parts, so there's no reciprocating arm, no danger of shock."
The technology can handle a lateral misalignment of up to six inches.
Monterey, a coastal tourist destination, hopes to convert its waterfront trolleys to electric power to move visitors without the exhaust and noise of diesel, Smith said. A successful demonstration could open the door to major transit systems, such as San Francisco and Washington, D.C., where electric buses are powered from overhead lines.
"You are no longer tied to one route. You have a small battery onboard to cross from one area of electrified infrastructure to another," Gilchrist said. "Washington, D.C., is interested because they don't want wires hung in the historic district."
The technology would also eliminate the need for contact brushes that generate grit that falls on the buses.
No strings attached
Utah State University's Energy Dynamics Laboratory has developed a way to transfer electrical power across a 10-inch gap with enough efficiency to make it commercially viable for use in public transit. A company has been created to develop demonstration projects, including one to electrify a University of Utah shuttle bus route. The technology will be discussed at the Conference on Electric Roads and Vehicles Feb. 27-28 in Park City.