Purdue Prof. Scott Sudhoff and team complete a successful test of a new type of electric motor
Researchers at Purdue University’s Elmore Family School of Electrical and Computer Engineering have completed a successful test of the world's first (and presently only) dual rotor homopolar alternating current machine, or DHAM for short, a new type of electric motor. Scott Sudhoff, Michael and Katherine Birck Professor of ECE, says the machine is designed to reduce the need for heavy rare earth materials in electric and hybrid vehicle motors, though there are many other applications.
He says until now, permanent magnet alternating current (PMAC) machines have been the dominant source of motors in the car market and other applications that need power dense AC machines. Sudhoff says these machines typically utilize rare earth materials for their construction. He says non-rare earth PMAC machines have been realized; however, they suffer from lower power densities. Sudhoff says the DHAM can be constructed without rare-earth materials while meeting the torque requirements of the vehicular market. He says the US Department of Energy provided most of the funding for this research out of the Vehicle Technology Office. Sudhoff says the agency has been seeking alternatives to the use of heavy rare-earth materials, which have significant price volatility.
“One of the features of this new machine is that we can get away with very relatively low performance, less expensive, magnets,” he says. “This is a machine that's going to be potentially a lot easier and less expensive to make, which will help reduce the price of electric and hybrid vehicles.”
Sudhoff says the magnets in the DHAM don’t require rare earth materials because of the machine’s superior cooling qualities. He says it also has a wide constant power speed range, making it ideal for not only electric vehicles, but also applications such as energy storage systems.