Design and tests of a four-layer fractional-slot Interior Permanent Magnet motor

This paper deals with the design and test of an Interior Permanent Magnet (IPM) machine which exhibits advanced features. At first it adopts fractional-slot (FS) non-overlapped coil windings which reduces the end winding length and then Joule losses and machine cost. As a consequence higher rated current can be supplied and therefore higher torque density and higher efficiency in a wide operating region can be reached. Then, the rotor saliency increases the performance in flux-weakening operating region and the fault-tolerance capability.