18-090 Shifted Fractional Pitch Wye-Delta Multilayer Winding of AC Machines for Space Harmonic Elimination

April 27, 2018

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Phase windings of AC electric machines are housed in stator slots. Conventional windings are fully pitched meaning the angle between stator coils is equal to the angle between rotor poles. Concentrated wound designs have lower end-winding length and lower stator conductor losses but higher harmonics that increase iron loss, decrease power factor, and increase torque ripple.

This novel winding concept has the positive features of concentrated windings and eliminates issues with space harmonics from stator MMF. Resulting machines have:

  • enhanced torque-producing winding factor with shorter end winding length
  • compact structure
  • improved torque density, efficiency, and power factor
  • reduced core losses, torque ripple, and conductor losses.

This proposed winding concept is applicable for both double and multilayer wound electric machine topologies including but not limited to the permanent magnet synchronous machine, synchronous machine, reluctance machine, induction machine for both inner and outer rotor configuration.


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