GeneratorSE: A Sizing Tool for Variable-Speed Wind Turbine Generators

Latha Sethuraman, Katherine Dykes

Research output: NRELTechnical Report


This report documents a set of analytical models employed by the optimization algorithms within the GeneratorSE framework. The initial values and boundary conditions employed for the generation of the various designs and initial estimates for basic design dimensions, masses, and efficiency for the four different models of generators are presented and compared with empirical data collected from previous studies and some existing commercial turbines. These models include designs applicable for variable-speed, high-torque application featuring direct-drive synchronous generators and low-torque application featuring induction generators. In all of the four models presented, the main focus of optimization is electromagnetic design with the exception of permanent-magnet and wire-wound synchronous generators, wherein the structural design is also optimized. Thermal design is accommodated in GeneratorSE as a secondary attribute by limiting the winding current densities to acceptable limits. A preliminary validation of electromagnetic design was carried out by comparing the optimized magnetic loading against those predicted by numerical simulation in FEMM4.2, a finite-element software for analyzing electromagnetic and thermal physics problems for electrical machines. For direct-drive synchronous generators, the analytical models for the structural design are validated by static structural analysis in ANSYS.
Original languageAmerican English
Number of pages91
StatePublished - 2017

NREL Publication Number

  • NREL/TP-5000-66462


  • cost
  • doubly-fed induction
  • efficiency
  • electrically excited synchronous generator
  • mass
  • permanent magnet generator
  • squirrel cage


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