Benefits of increasing the number of stator phases in terms of winding construction technology in high-power electric machines

The adoption of multi-phase stator topologies in electrical machine design brings well-known advantages in terms of power segmentation, reliability and performance. In addition to these functional benefits, which are independent of machine size, this paper highlights how the use of more than three phases can lead to construction advantages when applied to electric machines of large size. The advantages relate to the winding manufacturing technology, which can be retained similar to that of small machines in presence of a multi-phase solution, while a traditional three-phase one would imply a more costly Roebel bar construction. The point is justified in terms of machine sizing equations and is assessed referring to some built high-power multi-phase machines for industrial and ship propulsion use.