By combining permanent magnets and field winding into a wound rotor system, researchers at Purdue University have come up with a way to reduce the size of some moderate-to-low electric generators while also increasing the efficiency.    What is a Wound Rotor System? A wound-rotor synchronous machine, like the one used in this study, contains a field winding on the rotor. This field winding is a group of insulated current-carrying coils that are used to create a rotating magnetic field and regulate the output voltage.   Introducing: The Parallel Inner-Magnet Device In the new device, called the Purdue parallel inner-magnet device, a rotating magnetic field regulates the output voltage thanks to a wound rotor. Regulation with this device comes with lower losses than a conventional machine thanks to the device’s hybrid solution, which “creates some of the field with a permanent magnet and some of the field with a field winding,” said Scott Sudhoff, the Michael and Katherine Birck Professor of Electrical and Computer Engineering in Purdue’s College of Engineering. Losses are still associated with this winding, as it produces heat that has to be eliminated from the spinning rotor.    Permanent magnets can also be used to generate the magnetic field with less loss and heat generation, but this approach doesn’t aid in voltage regulation as this device does. The electric generators used in this study can be found in cars, aircraft, and microgrids, where there’s a strong desire to reduce the size and increase the efficiency of the devices.    How can it be used?  According to Omar Laldin, a former Ph.D. student of Sudhoff, the device can be used in a variety of AC (alternating current) and DC (direct current) generator applications. The main issues right now are finding the best machine architecture in terms of merging the two field sources, electromagnetic damping, and fault performance. The team has worked with the Purdue Research Foundation Office of Technology Commercialization to patent the technology and is looking for commercialization partners.   Stay Up-to-Date on All Things Magnetic with Apex Magnets  There are always exciting things going on in the world of magnetism. To stay up-to-date on this story and others like it, subscribe to our newsletter