Moving Forward

UA researchers play critical role in innovation for electric vehicles

Two people work in a electrical engineering lab at The University of Alabama.
Graduate student Hoyun Jay Won, left, and undergraduate student Jonathan Platt work with magnetic materials as part of research to improve electric vehicles.

The electric motor has been around nearly two centuries, but it was largely abandoned for use in cars until this century. Its recently sustained emergence in the personal vehicle market is spurring innovation needed for it to replace combustion engines on a large scale.

There is no one, agreed-upon motor design, and auto manufacturers are busy developing technologies to give their models the leg up on their competitors. The combustion engine, on the other hand, is settled technology with refinements along the way to boost either power or fuel economy, for instance.

“Compared to internal combustion engines, which have been the subject of intense research and engineering efforts for more than a century, vehicle electrification technologies are still immature, and, like all immature technologies, they need further improvement,” said Dr. Yang-Ki Hong, an engineering researcher at The University of Alabama.

Hong leads a group of campus researchers focused on improving electric motors in vehicles by improving efficiency and reducing costs while relying on more sustainable materials.

“We can help electric vehicles increase their share of the automotive market with our technology,” Hong said.

UA is one of four universities selected by the National Science Foundation to team with government agencies and private companies to tackle challenges facing technological advances in automobiles as part of an NSF Industry/University Cooperative Research Center, or IUCRC, for Efficient Vehicles and Sustainable Transportation Systems. It was established to support efforts by the automotive and ground transportation industries to meet new federal regulations governing vehicle fuel economy and emissions, as well as society’s expectations for improved sustainability.

A man stands in an electrical engineering lab for a portrait.
Dr. Yang-Ki Hong

“At the dawn of the era of electric vehicles, this research program is developing a state-wide research network between an academic institution and automotive industries in support of the overall R&D efforts in the electric vehicle in the state of Alabama,” Hong said.

As part of the center’s work, Hong’s lab devised new technologies to lower production costs and allow electric vehicles to compete with the combustion engine’s ability to work efficiently in different circumstances.

Electric motors are fundamentally different from a combustion engine, even though both accomplish the goal of moving wheels. Combustion engines produce mechanical motion by burning a fuel, which, in cars, is typically the refined oil Americans call gasoline. Electric motors use the flow of magnetic fields and electric currents to produce mechanical motion.

Electric motors, employing a permanent magnet, are widely used by many automakers because of their high efficiency and torque density. However, a problem with many electric motors is the magnets used are from rare earth elements, materials that create their own continuous magnetic field. Rare-earth permanent magnets are the most powerful and efficient magnets, and their size and reliability suit them well for electric motors that use their magnetic field as power.

Rare earth elements are not abundant, mostly mined by one country, China, and they are expensive since, as the name suggests, they are rare.

“The vast majority of the cost of an electric motor is the cost of the magnet. That’s why we are trying to avoid rare-earth permanent magnet,” Hong said. “Even partially replaced rare earths bring about huge savings.”

Hong’s research group designed a motor that replaces many of the rare-earth permanent magnets with ferrite, a mixture of iron, oxygen and other metals, which is more common and cheaper to produce. The patent-pending technology has a lower magnetic flux than a rare earth permanent magnet, which Hong’s lab gets around by changing the design of the motor. It’s a necessary tradeoff, Hong said.

“We can help electric vehicles increase their share of the automotive market with our technology,” Hong said.

“Replacing rare-earth permanent magnets in these motors with rare-earth free permanent magnets will eliminate the possibility of large-scale disruptions in cost and supply that is intrinsic to dependence on a critical commodity available in small quantities from a single supplier,” he said.

Another innovation from Hong’s lab aims to overcome an issue unique to an electric vehicle, the inability to operate efficiently at higher speeds. Combustion engines tackle needing torque at different speeds by activating different combinations of gears in a transmission.

An electric vehicle does not have a transmission, operating at the same gear level no matter the speed. This can cause problems at high speeds such as on the open highway, where the electric motor runs inefficiently.

The solution designed at UA is called the EnergyShifting Permanent Magnet Synchronous Machine, which has a pending patent. The invention realizes high efficiency at both low and high speeds by switching the electrical current between two stators to rotate one shared rotor. The rotor runs by magnetic energy provided by the stator.

Man with gloves uses electronic equipment in a lab at The University of Alabama.
Graduate student Hoyun Jay Won measures properties of magnetic materials as part of research into electric motors.

The idea avoids adding the complexity of transmission and gearbox to electric vehicles, and some within the auto industry are interested in the energy-shifting electric motor.

“Our uniqueness is that we have combined this magnet with a simple motor that allows for the compact size of the motor structures,” said Hoyun Jay Won, a graduate student in Hong’s lab.

Performance calculations on the design show it could add up to 20 miles per charge for an electric vehicle, a significant boost vital in reducing recharging of vehicles. This brings down the cost of ownership and the need to draw energy from the power grid.

“While the public thinks of electric vehicles as intrinsically clean, the electricity that drives them comes largely from stationary power plants, or in the case of most hybrids, internal combustion engines,” Hong said. “We can reduce this ‘upstream’ environmental impact by improving the sustainability of the primary power sources – a process well underway – and designing and deploying powertrains that are more efficient both at the component and system levels.”

Dr. Hong is professor and the E. A. “Larry” Drummond Endowed Chair of Electrical and Computer Engineering.