Design Optimization of a Direct-Drive Wind Generator With a Reluctance Rotor and a Flux Intensifying Stator Using Different PM Types

Ali Mohammadi, Oluwaseun A. Badewa, Yaser Chulaee, Donovin D. Lewis, Somasundaram Essakiappan, Madhav Manjrekar, Dan M. Ionel

Research output: Contribution to journalArticlepeer-review


This paper presents a large-scale multi-objective design optimization for a direct-drive wind turbine generator concept that is based upon an experimentally validated computational model for a small-scale prototype motor of the same type. By integrating an outer reluctance -type rotor and a segmented stator with toroidally wound single-coil modules containing spoke -type PMs, the design optimization aims to minimize losses, active mass, and torque ripple while adhering to a power factor constraint. The AC windings and PMs are positioned in the stator and this concept enhances flux concentration, enabling the use of more affordable high energy non-rare- earth (special type) magnets. The exterior rotor follows a simplified reluctance -type configuration, eliminating active electromagnetic components. The operational principle, described in detail, guides design studies using electromagnetic 2D finite element analysis (FEA), showcasing the potential of this configuration to match rare- earth PM performance, with special type PMs, thus addressing cost and supply challenges. Furthermore, alternative materials including the substitution of aluminum wire for copper wire, have also been investigated in this study. The proposed multi-objective design optimization uses the response surface method (RSM) to initiate the optimization and the results on a 3MW, 15 rpm generator, highlight the benefits of this topology, achieving competitive metrics like goodness, specific thrust, and efficiency without rare- earth permanent magnets.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalIEEE Transactions on Industry Applications
StateAccepted/In press - 2024

Bibliographical note

Publisher Copyright:


  • Direct-drive generator
  • Generators
  • Prototypes
  • Rotors
  • Stator windings
  • Topology
  • Wind turbines
  • Windings
  • design optimization
  • double-salient
  • flux-intensifying topology
  • flux-reversal
  • flux-switching
  • spoke permanent magnets
  • synchronous machine
  • toroidal winding
  • wind turbine

ASJC Scopus subject areas

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


Dive into the research topics of 'Design Optimization of a Direct-Drive Wind Generator With a Reluctance Rotor and a Flux Intensifying Stator Using Different PM Types'. Together they form a unique fingerprint.

Cite this