Design Optimization of a High Torque Density Spoke-Type PM Motor for a Formula e Race Drive Cycle

Alireza Fatemi, Dan M. Ionel, Mircea Popescu, Yew Chuan Chong, Nabeel A.O. Demerdash

Research output: Contribution to journalArticlepeer-review

96 Scopus citations


Performance trade offs for achieving high torque density and high drive-cycle efficiency in spoke-type permanent magnet (PM) motors are investigated. Unlike the traditional method, which relies on analytical equations, this trade-off study is conducted through a statistical analysis of the Pareto-optimal design candidates resulting from a large-scale design optimization of an example traction machine over a Le Mans-based drive cycle. In the design optimization process, both low-speed and extended-speed/field-weakening operating regions are evaluated using high-fidelity electromagnetic finite element (FE) simulations with an objective to simultaneously increase the torque density and decrease the power losses over the high energy-throughput-zones of the machine torque-speed plane. The resultant 3400 design candidates are utilized to investigate the impact of increasing power density on other important performance metrics such as power losses, PM demagnetization, and torque ripple. This analysis is supplemented by multiphysics simulation of three counterpart optimized designs and successful experimental verification of a prototype of one of those three designs which represents a record high power density motor in traction applications.

Original languageEnglish
Article number8374899
Pages (from-to)4343-4354
Number of pages12
JournalIEEE Transactions on Industry Applications
Issue number5
StatePublished - Sep 1 2018

Bibliographical note

Publisher Copyright:
© 1972-2012 IEEE.


  • Drive-cycle design optimization
  • electric race vehicles
  • power density
  • spoke-type PM motors
  • torque density
  • traction motors

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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