Iowa State engineer working to increase efficiency of electric motors by optimizing performance in preferred direction of rotation

26 January 2012

Supported by a five-year, $400,000 grant (Award Nº 0846337) from the National Science Foundation’s Faculty Early Career Development Program, Iowa State University assistant professor of electrical and computer engineering Dionysios Aliprantis is working to increase the efficiency of electric motors by optimizing performance in a preferred direction of rotation.

The objective of his “Sculpting Electric Machines for Unidirectional Motion” project is to study the improvement in electric machine operation when unidirectional motion is taken into account, since the vast majority of generators and motors rotate in a single direction.

The approach is to sculpt precisely the stator and rotor surfaces, thus affecting the electromagnetic field in the air gap so that the production of electromechanical torque is increased. The transformative value of this approach rests in its generality, being applicable to rotating machines of any power rating, material, or type.

The research involves analysis using the electromagnetic finite element method embedded inside an optimization loop, by adapting shape sensitivity-based design methods.

The goal is to get more power out of the same size motor. Or, that could mean getting the same power with a smaller motor. I’m looking for a little bit of increase, maybe 5 percent or 1 percent. But multiply that number by the number of hybrid cars, let’s say, and you could get savings in the billions of dollars. The potential here could be huge.

—Dionysios Aliprantis

The teeth that hold coils of wire within an electric motor, for example, have typically been built with a symmetrical shape that maintains performance in either direction. By making the teeth asymmetrical, the engineers hope the motor can pick up some power when rotating in the preferred direction.

We are trying to develop a systematic way of getting to the right shape. This idea is very simple, but motors are still being designed using techniques that are essentially one hundred years old.

—Dionysios Aliprantis