Segmented Hairpin Topology for Reduced Losses at High-Frequency Operations

Eraldo Preci, Stefano Nuzzo, Giorgio Valente, David Gerada, Davide Barater, Michele Degano, Giampaolo Buticchi, Chris Gerada

Research output: Journal PublicationArticlepeer-review

25 Citations (Scopus)


Nowadays, one of the key challenges in transport electrification is the reduction of components' size and weight. The electrical machine plays a relevant role in this regard. Designing machines with higher rotational speeds and excitation frequencies is one of the most effective solutions to increase power densities, but this comes at the cost of increased losses in cores and windings. This challenge is even more pronounced in preformed windings, such as hairpins, which enable higher slot fill factors and shorten manufacturing cycle times. In this work, an improved hairpin winding concept is proposed, aiming to minimize high-frequency losses while maintaining the benefits deriving from the implementation of hairpin windings onto electrical machines. Analytical and finite element models are first used to assess the high-frequency losses in the proposed winding concept, namely the segmented hairpin, proving the benefits compared to conventional layouts. Experimental tests are also performed on a number of motorettes comprising both conventional and proposed segmented hairpin configurations. Finally, these experimental results are compared against those collected from motorettes equipped with random windings, demonstrating the competitiveness of the segmented hairpin layout even at high-frequency operations.

Original languageEnglish
Pages (from-to)688-698
Number of pages11
JournalIEEE Transactions on Transportation Electrification
Issue number1
Publication statusPublished - 1 Mar 2022


  • AC losses
  • analytic model
  • automotive
  • electrical machine
  • end winding
  • experimental
  • hairpin winding
  • high frequency
  • mass production
  • random
  • segmented hairpin
  • winding

ASJC Scopus subject areas

  • Automotive Engineering
  • Transportation
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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