Considerations on the Preliminary Sizing of Electrical Machines with Hairpin Windings

Abstract— Although the standard preliminary sizing of electrical machines equipping random windings is well
consolidated and is worldwide acknowledged to be a good starting point for the design, there is no proof of accuracy and
confidence when it comes to hairpin windings. This winding technology is gaining extensive attention due to its inherently
high slot fill factor, good heat dissipation, strong rigidity, and short end-windings. These features make hairpin windings a
potential candidate for some traction application to enhance power and/or torque densities. In this paper, a comparative
design is done using the classical sizing tools available in the literature between two surface-mounted permanent magnet
synchronous machines, one featuring a random winding and one with a hairpin layout. The study aims at highlighting the hairpin
winding challenges at high frequency operations and at showing limits of applicability of these standard approaches when
applied to this technology. For verification purposes, finite element evaluations are also performed.

© 20XX IEEE.  Personal use of this material is permitted.  Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.