Electric generators have a plethora of uses—ranging from automotive to aircraft to microgrids. There is currently a strong desire to reduce the size and increase the efficiency of the devices.
Researchers at Purdue University have come up with an effective way to reduce the size and increase the efficiency of the moderate- to low-power electric generators used in those applications.
A wound rotor synchronous machine contains a field winding—a group of insulated current-carrying coils—on the rotor used to create a rotating magnetic field and regulate the output voltage. Associated with this winding are losses, which generate heat that must be removed from the spinning rotor. Permanent magnets can also be used to generate the magnetic field with much less loss and heat generation, but this approach does not facilitate output voltage regulation.