Additive Manufacturing of Shaped Profile Windings for Minimal AC Loss in Electrical Machines

Metal additive manufacturing enables production of copper and aluminium parts exhibiting unmatched geometric freedom, giving rise to new possibilities in the winding design of electrical machines and wound passive components. Early adopters of additive manufacturing are primarily concerned with improving power-density or efficiency by increasing slot fill-factor, optimizing end-winding topology or incorporating cooling channels into the conductors. In this article, a method of minimizing the elevated ac loss present in open slot electrical machine topologies is presented, in which individual conductor profiles are shaped according to their magnetic environment. Such shaped profile windings are shown to exhibit operating mode dependent loss behavior giving them potential for efficiency improvement in applications with a dominant operating mode such as electric vehicle traction, aerospace propulsion fans, and generators. For the first time, the conductor shaping method and associated benefits are demonstrated by the retrospective design, additive manufacture, and experimental test of a three-phase set of shaped profile windings for a concentrated wound, open slot, permanent magnet electrical machine.