Yue Zhao

Prestigious grant will power electrical engineering professors’ research

Electrical Engineering Assistant Professor Yue Zhao is trying to change how we get around.

What began as an interest in battery-powered toys as a boy in China has led Zhou to the University of Arkansas, where he has received one of the National Science Foundation’s most prestigious awards, the Early Faculty Career Development Award, known colloquially as a CAREER award.

The NSF describes the $500,000 award as its most prestigious award in support of junior faculty who exemplify the role of teacher-scholars.

For Zhao, it’s another step toward his goal of using electrical engineering to make motors in vehicles on land, at sea and in the air, run as efficiently as possible.

"Silicon carbide can increase power density by four times. That means a significantly smaller size and less weight, which tracks to miles per gallon and savings for drivers."

From toys to tractors

As a boy, Zhao spent his free time learning all he could about the electrical systems around him.

“When I was young, growing up in China, I liked battery powered cars and electronics,” he said.

That interest led to an undergraduate career studying electrical engineering. During his time at Beijing University of Aeronautics and Astronautics, Zhao developed in interest in robotics and electric vehicles.

After graduating, Zhao moved in 2010 to the University of Nebraska, where he began his doctoral studies in electrical engineering and had a chance to explore his interest in electric vehicles in a big way.

“My first project was sponsored John Deere,” Zhao said. “We were developing an advanced control for tractor drive systems. There was a really large John Deere research effort at the time to develop hybrid tractors and other agriculture equipment.”

That project, Zhao said, aimed to reduce fuel use in tractors by 25 percent, which would have a major environmental and economic impact.

Zhao earned four patents during his time at the University of Nebraska, and the concepts he developed there became the foundation for his CAREER award research.

After graduating from the University of Nebraska, Zhao taught for a year at Virginia Commonwealth University before joining the University of Arkansas faculty in 2016.

Tools of the trade

Zhao credits the strength of University of Arkansas Electrical Engineering department’s research facilities as one of the major factors in his success, and in his selection for the CAREER award.

His work is inspired by a circuit design project he conducted with Dr. Alan Mantooth at the Center for Power Optimization of Electro-Thermal Systems, known as POETS, in the Arkansas Engineering Research and Technology Park Fayetteville. The center is a collaboration between the University of Arkansas, Stanford University, Howard University and the University of Illinois at Urbana-Champaign.

That research involved using powerful, high-density inverters, which inspired Zhao to look into the control algorithms that convert direct currents from a battery into the alternating currents needed to operate a motor.

Most of those drives are currently made of silicon, which can only switch at a frequency of 10 kilohertz. Zhao’s proposal suggests using silicon carbide, which could be up to 10 times faster.

That would make motors more efficient, which translates to a direct impact on miles-per-gallon for hybrid vehicles of all sizes that use both fossil fuels and electricity, Zhao said.

That switching process is at the heart of powering an electrical motor, and Dr. Zhao’s CAREER award research focuses on the software that optimizes that process.

It’s an avenue few researchers have explored.

“People have been working on the hardware to optimize (the switching process),” Zhao said. “But if we can optimize the software, there will be a long-term impact on the automotive and aerospace industries.”

"As more electric powered motors are used in vehicles, aircraft and ships, we could eventually reduce carbon emissions by 20 percent. That’s a huge benefit to everybody in the world."

Improving efficiency for industry and individuals

Zhao said he anticipates his research will benefit three main groups. In the short term, other researchers will benefit as the research establishes a new baseline for what’s possible in the field of power electronics. Using silicon carbide isn’t yet popular, but if it can be proven to work, researchers around the world will have a variety of new avenues to explore.

The second group Zhao hopes will benefit are businesses who use electric hybrid vehicles on a large scale. As companies continue seek more efficient ways to move goods by land, air and water, a widespread adoption of silicon carbide motor drivers could lead to substantial cost savings.

“Silicon carbide can increase power density by four times,” Zhao said. “That means a significantly smaller size and less weight, which tracks to miles per gallon and savings for drivers.”

If the technology evolves to mass production, Zhao said, the entire planet would benefit. “As more electric powered motors are used in vehicles, aircraft and ships, we could eventually reduce carbon emissions by 20 percent,” he said. “That’s a huge benefit to everybody in the world.”

Powering the next generation

Like all CAREER awards, Zhao’s project includes an educational component. For his part, Zhao saw an opportunity to position students for success while also enhancing the quality of electrical engineering education at the University of Arkansas.

A portion of the $500,000 grant will help fund studies for three students: one Ph.D. candidate, one master’s student and an undergraduate.

Zhao said he wants his coursework to focus on technologies and research that students will face when they enter the power electronics job market, including being prepared to implement solutions related to new silicon carbide technology.

“In auto manufacturing, in chip manufacturing, they’ll need a lot of talent,” Zhao said. “in my course, I’ll try to put the latest research findings into the class so students can get more of an idea of what’s state-of-the-art and what the industry really looks like today.”

First timer

Earning a CAREER award is a prestigious achievement in itself, but Zhao’s award includes an added success: it only took him one try.

Grants from the National Science Foundation are highly competitive, and only a fraction of applications are awarded. In many cases, award winners have applied five, ten times or more.

“When I heard about this, I was shocked,” Zhao said, noting the success was not his alone.

“This isn’t just something for me,” he said. “This is an achievement for the whole power electronics faculty. Ten-plus faculty members in this area have given tremendous support to this project.”