Faster. Smaller. Smarter. For new faculty member Eric Severson, these three qualities are the key to reducing wasted electrical energy. Severson, who joined the Department of Electrical and Computer Engineering and the Grainger Institute for Engineering in fall 2017, is passionate about developing clean technologies and finding better, more efficient ways to use energy.
“Right now, there’s a tremendous amount of energy in the U.S. that’s wasted by motors in large industrial systems. In fact, 20hp and larger industrial motors consume up to 15 percent of U.S. electric energy and waste up to 80 percent of that,” he says.
And with 45 percent of the world’s electric energy being consumed by electric motor systems, the need to replace inefficient, outdated motor systems with new, highly efficient technology is a challenge he is excited to address.
Severson’s current research has the potential to significantly reduce global energy consumption. “My focus area in the near term is on magnetic levitation,” he says. “It’s a way to take an electric motor’s existing magnetic field and use it to create magnetic bearing forces—a technology I call bearingless motors.”
Eliminating the bearings means that motors can operate much faster, which allows them to be significantly smaller. Without bearings, there’s no drag, or loss of energy, and more motors can fit into a compact area. And because bearings are typically the first component in a motor system to fail, the absence of bearings is a game changer for the durability and reliability of the motor.
Severson’s take on bearingless motor technology actually developed as a result of his PhD research on flywheel energy storage at the University of Minnesota. Flywheel energy storage—when a motor stores up kinetic energy by spinning a rotating mass up to a high speed—already has many advantages over other utility-scale energy storage technologies, like pumped hydroelectric, batteries and compressed air energy storage. Not only do flywheels allow renewable energies onto the power grid, but they’re also highly responsive and environmentally safe. The disadvantages? The intrinsic loss and low durability of the motor’s bearings. However, the use of bearingless motors in flywheel energy storage could have very meaningful societal impacts.
Applications for bearingless motors run the gamut from electric energy storage for autonomous vehicles to large industrial systems, like HVAC compressor chillers and wastewater aeration treatment. For example, one aspect of the U.S. Clean Water Act dictates that treat our sewage by injecting air into it to help bacteria biodegrade organic waste. There are about 15,000 treatment facilities in the United States and the motors currently used for wastewater aeration treatment fall into the category of motors that waste 80 percent of their energy. Not only that, but these motors are sized for sewage flow in the event of a hurricane or other worst-case scenario, injecting more than quadruple the flow of air needed a majority of the time.
“We need more intelligent motor systems with the ability to vary the power output instead of always drawing fixed power from the grid,” says Severson. “I’m working on solving challenges like these to help us be more sustainable and have cleaner energy sources, as well as use our energy more efficiently.”
Severson is very interested in shaping technology and the way we use it. That’s why, after spending some time in the private sector and considering starting his own company, he ultimately decided to return to research. “The ability to collaborate with people and not worry about competition, as well as the freedom to bring a vision to fruition, is all very exciting to me,” he says. “I’m very excited about the multidisciplinary mission of the Grainger Institute for Engineering, an idea that’s also wholeheartedly embraced by the entire university. Exciting things can happen when you collaborate and work together.”
In fall 2017, Severson is teaching Fundamentals of Magnetically Levitated Motor Systems, a special topics graduate student course based on his research.
Author: Adrienne Nienow