Eric Severson

Area of Focus: Area of focus: Ph.D. (Electrical Engineering) – High Speed bearingless motors

Graduation Year: June 2015

“I really liked the creative challenge of research—having an objective and the freedom to figure out how to meet the objective, and then getting to figure out how to use all of the tools and expertise available at the U to do this.”

What do electrical engineers do?

Eric Severson leads an extremely busy life these days. As a postdoctoral associate, he continues working on bearingless motors, the subject of his doctoral research. His attention however has now shifted from flywheel energy storage to development of a very low cost, high efficiency, high speed electric motor. In the United States, electric motors 100hp and larger make up 10% of the total electric energy consumed. When combined with the fact that these motors also tend to operate inefficiently, with 30 to 80% of the electric power lost as heat, we are faced with a very significant problem of wasted energy.

Current solutions to this problem are largely based around magnetic bearings and permanent magnet motors, which are very expensive and complicated. But Eric has a solution that could counter these challenges. In a voice charged with enthusiasm he says, “The bearingless motor that I am developing is a much simpler and lower cost solution, and the patent on it is currently pending.”

But this is where the story begins

Eric grew up on a hobby farm in Chanhassen, MN, riding horses on the trails around town. After high school, he moved to Michigan to start his undergraduate program at Michigan Technological University. But two years later, interest in the English program and his quest for experience in a research university drew him to the University of Minnesota to pursue a double major in electrical engineering and English. A rather unusual combination one might say, but Eric contends that he found the disparate nature of the two majors refreshing and insightful. As to his experience as an undergraduate student, Eric says he valued the small class sizes and the sequenced nature of the electrical engineering program which meant that you inevitably got to know your classmates fairly well, important for building a support system during the grueling 2 years in the major.

As a student in the University Honors Program for the electrical engineering major, Eric had the opportunity to work with ECE faculty Prof. Ramesh Harjani for his senior honors thesis. He was tasked with designing a power supply for laptops that was 75% smaller in size than the prevailing power supplies which were fairly large “bricks” as Eric calls them.

Eric pored over patents and papers on the state of the art, even as he worked in the lab; he found the experience fascinating. By the end of the allotted 2 semesters for a senior honors thesis, he had a working prototype. Eric and a friend teamed up to enter the prototype in the MN Cup (Student Division) and ended up as semifinalists. Participating in the various MN Cup events was his first brush with networking with entrepreneurs, mentors, and investors, and he was hooked. Eric soon graduated and worked for Forward Pay Systems in Eden Prairie for a short while. But the research experience he was exposed to in Prof. Harjani’s lab left him longing for more.

“I really liked the creative challenge of research—having an objective and the freedom to figure out how to meet the objective, and then getting to figure out how to use all of the tools and expertise available at the U to do this.”

Interest in Research

Eric returned to the University as a doctoral student. He took a course on power electronics taught by Prof. Ned Mohan (who was to later become his doctoral thesis advisor), and found the idea of using his technical skills to contribute to renewable energies technology exhilarating. With the help and encouragement of Prof. Mohan, he applied for national fellowships with the NSF and the Department of Defense (DoD).

Eric was awarded the Graduate Research Fellowship Program by the NSF and the National Defense Science and Engineering Graduate Fellowship by the DoD, which funded 5 years of his doctoral program. Eric was also the recipient of the University’s doctoral dissertation fellowship which funded the final year of his doctoral work.

He defended his dissertation in early June 2015, 6 weeks after the birth of his daughter! (Eric’s wife Annie brought Marie along to support him during the presentation.)

Eric feels very fortunate to have had Prof. Mohan as an advisor. “He gave me the freedom and encouragement to define my own project, while still keeping me focused and on track. Apart from research, Prof Mohan has a strong teaching focus and encourages all of his students to get involved in some way. For me, this meant helping with his renewable energies curriculum reform faculty workshops and working as a part time TA for one of his graduate level courses. It is very nice to get perspective beyond the nitty gritty of one’s research and engage with the larger community.”

Under his guidance, Eric started researching the challenges of flywheel energy storage. The power grid typically cannot dictate the generation of wind and solar power because they are dependent on weather conditions. When you have a lot of such renewables-based generation on the power grid, stable power supply can be a problem, but one that can be solved by storing energy. Flywheels are an interesting alternative to conventional batteries for storage because they do not contain hazardous chemicals and you can charge and discharge them an infinite number of times. Batteries on the other hand wear out after a few thousand charge/discharge cycles. However, the challenge with flywheel energy storage is that it traditionally has very high upfront material costs as well as a high rate of self-discharge. For Eric, the goal was to create a flywheel energy storage module that was inexpensive enough to be used on the power grid to enable higher levels of renewable generation.

So Eric’s research evolved into the development of a type of bearingless motor called an AC homopolar motor. A bearingless motor, as the name suggests, is a motor without bearings. It uses its magnetic field (the same magnetic field that is used to create torque in any type of motor) to also create magnetic bearing forces to keep its shaft centered. The goal with the new flywheel system is to reduce cost by eliminating the need for separate magnetic bearing hardware, and solve the self-discharge problem.

Bearingless motor technology has historically had performance challenges—you either get good magnetic bearing capabilities or good motor capabilities. Eric spent a lot of time working on overcoming this performance trade-off, and ultimately filed a patent application.

Taking it to the Market

Seeing the value in commercializing such a high impact technology and making it accessible, Eric has reached out to resources within the University that can support him in his task. He participated in MIN-CORP’s course titled STARTUP (MGMT 4100/6100), offered through the Carlson School of Management.

“The course was eye-opening for me in a lot of ways,” says Eric. “I learned about customer discovery and how to make cold calls and network my way to key decision makers. The goal was to validate that customers really want what we think they want.”

With the help of the intensive 2-credit course, Eric zeroed in on his target market in turbine-driven machinery, where his bearingless motor will offer customers the highest value in terms of cost savings and energy efficiency.

Besides the STARTUP course, Eric has also drawn on the resources offered by the University’s Office of Technology Commercialization. He is especially grateful for the support he has received from Kevin Nickels, business development specialist, as he learns the details of starting a business.

“The goal,” Eric says, barely concealing the excitement in his voice, “is to create a University startup to develop and manufacture these bearingless motors. In the coming months, I will be working with OTC’s Venture Center to make this happen.”

And that is just one of the things that electrical engineers do.