Use the [Magnetic] Force for Good: Sustainability Through Magnetic Levitation

Electric motors pump our water, heat and cool our homes and offices, drive critical medical and surgical equipment, and, increasingly, operate our transportation systems. Approximately 99% of the world’s electric energy is produced by a rotating generator and 45% of that energy is consumed by an electric motor. The efficiency of this technology is vital in enabling our energy sustainability and reducing our carbon footprint. The reliability and lifetime of this technology have severe, and sometimes life-altering, consequences. Today’s motor technology largely relies upon mechanical bearings to support the motor’s shaft. These bearings are the first components to fail, create frictional losses, and rely on lubricants that create contamination challenges and require periodic maintenance. In short, bearings are the Achilles’ heel of modern electric motors.

This seminar will explore the use of actively controlled magnetic forces to levitate the motor shaft, eliminating mechanical bearings and the problems associated with them. The working principles of traditional magnetic levitation technology (active magnetic bearings) will be reviewed and used to explain why this technology has not been successfully applied to the most high-impact motor applications. Research into “bearingless” motors offers a new levitation approach by manipulating the inherent magnetic force capability of all electric motors. While traditional motors are carefully designed to prevent shaft forces, the bearingless motor concept controls these forces to make the motor simultaneously function as an active magnetic bearing. The seminar will showcase the potential of bearingless technology to revolutionize motor systems of critical importance for energy and sustainability—from industrial compressors and blowers, such as those found in HVAC systems and wastewater aeration equipment, to power grid flywheel energy storage devices and electric turbochargers in fuel-efficient vehicles.


Prof. Eric Severson
University of Wisconsin-Madison

Eric Severson received his PhD from the University of Minnesota in 2015. In 2017, Severson joined the faculty of the Electrical and Computer Engineering Department at the University of Wisconsin-Madison. He currently holds the University of Wisconsin College of Engineering’s named Grainger Assistant Professorship and is an associate director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC). Severson received the 2020 NSF CAREER award for electric machines that can be actuated across all six degrees of freedom. Severson’s research interests include design and control of electric machines and power electronics, with focus areas in bearingless motors, magnetic bearings, flywheel energy storage, and off-highway vehicle and hydraulic system electrification. He is currently the guest editor of a special issue of the IEEE Transactions on Industrial Applications journal on Magnetically Levitated Motor Systems.

Read the full article at: