Design to Reduce Rotor Losses in Fault-Tolerant Permanent-Magnet Machines

This paper designs a new rotor topology of a fault-tolerant permanent-magnet (FTPM) machine with fractional-slot concentrated winding in order to reduce rotor losses, demagnetization risk, and temperature. The key is the appropriate flux barriers, which are designed in rotor yoke. First, the structure feature and losses of rotor are analyzed. An analytical expression is derived by the simplified permeance model to evaluate the armature reaction magnetic field of the newly designed FTPM machine. Second, both the newly designed and the original machines are optimized for a given set of specifications, and their performances are comparatively analyzed by using finite-element method. Finally, some experiments on the prototypes of both FTPM machines are carried out for validation.