Abstract: A synchronous machine and related systems include a stator and rotor separated by an air gap. The rotor includes a rotating DC power supply coupled to exciter windings disposed adjacent the air gap. Power from air gap harmonics, including air gap slot harmonics induce current in the exciter windings, which is rectified and supplied to the rotor field windings. In operation, a desired current level in the rotor field windings can be achieved through control of the DC power supply or superposition of harmonics into the stator winding current which induces the prescribed current in exciter windings.

Abstract: The subject matter described herein includes a multiphase fractional slot concentrated winding machine. One such machine includes a machine module including a rotor and a stator. The stator includes a plurality of radially extending teeth. Each tooth is individually wound with a coil. The machine further includes a multiphase series converter circuit physically connected to an end of the machine module to energize the coils for multiphase operation.

Abstract: The subject matter described herein includes a fan assembly for cooling an electric machine and an electric machine incorporating such a fan assembly. One exemplary fan assembly according to the subject matter described herein includes a first fan annulus for surrounding a portion of an electric machine. The fan assembly further includes a fan drive circuit for driving the first fan annulus separately from a drive mechanism of the electric machine. The first fan annulus is configured to be, when rotating to cool the electric machine, mechanically disconnected from a housing and a rotor of the electric machine and separated from the housing by radial gap.

Abstract: A rotor for an electric machine is provided that includes a magnet and a non-magnetic region located adjacent the magnet. The non-magnetic region has an intrusion extending into the non-magnetic region.