Surface Permanent Magnet Synchronous Machines: High Speed Design and Limits

Gianvito Gallicchio, Mauro Di Nardo, Marco Palmieri, Mohammad Reza Ilkhani, Michele Degano, Chris Gerada, Francesco Cupertino

Research output: Journal PublicationArticlepeer-review

4 Citations (Scopus)


Surface permanent magnet synchronous machines are one of the most widely adopted machine topologies in high-speed applications where efficiency and power factor cannot be compromised. Although the design of such machine type has been extensively investigated in both industry and academia, this work aims at addressing its limitations when applied in high-speed applications. First, this paper proposes an accurate design methodology for continuous-duty high-speed surface-mounted permanent magnets synchronous machines, capable of accounting for the rise of the speed-dependent losses and structural needs with a limited impact on the computational burden. The outlined approach can be used to speed-up the initial design stage as it allows to reduce the number of solutions to evaluate before commencing the refinement stages required before the definition of the final design. Indeed, the introduced design approach is used to systematically assess the maximum power capability as function of the maximum speed and the airgap thickness for a given outer envelope and cooling system. The influence of the high-speed limiting factors is deeply investigated also considering their effects on the machine geometries providing the highest torque. The selection of the final design is discussed and justified. Experimental results of the 4.2 kW-80 kprm prototype validate the design methodology.

Original languageEnglish
Pages (from-to)1311-1324
Number of pages14
JournalIEEE Transactions on Energy Conversion
Issue number2
Publication statusPublished - 1 Jun 2023
Externally publishedYes


  • Analytical design
  • finite element analysis
  • high speed
  • permanent magnet motor
  • power density
  • sleeve
  • structural rotor design
  • synchronous motor

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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