In a free public seminar at 3:30 PM on February 20, in room 1115 of the Wisconsin Energy Institute, UW–Madison assistant professor of electrical and computer engineering Dan Ludois will give a talk on advanced electric machines for sustainable energy applications.
Electric machines (motors) are a cornerstone of our modern civilization, constituting 45% of all electricity utilization. The baseline high-tech motor technology in many applications are permanent magnet (PM) synchronous machines utilizing rare earth chemistries. These machines largely consist of three materials - steel, copper, and rare earth PM. Direct drive versions of these machines (no gearbox) use large amounts of rare earth PMs, especially magnet chemistries based on neodymium and dysprosium. Sources of electrical loss in these lower speed machines are predominantly resistive joule heating in the windings, putting copper in high demand to keep conduction losses low. In low speed machines, e.g. hundreds of RPM, PM material and copper are approximately ~10% and ~20% respectively, of the machine mass. Parallel to this, the embodied energy of materials, i.e. the energy used to produce the raw material prior to manufacturing, should also be taken into account. Despite PMs being only 10% of an electric machine’s mass, they are 50% of the total embodied energy of the raw materials. Machines are materials intensive. This talk will focus on two paths my group is pursuing to eliminate rare earth magnets form electric machines at a high level. Path 1) Replacing PMs with liquid cooled electromagnets powered by wireless power transfer, Path 2) Changing the fundamental force in the machine that makes torque, i.e. magnetostatics to electrostatics.