Axial Design Guidelines for Torque Ripple Reduction in Additively Manufactured Synchronous Reluctance Rotors

Torque ripple can cause noise and vibration in electric machines. To counteract this, various methods such as short pitch winding or sinusoidal pole contour are used to reduce flux density harmonics in the air gap and the resulting torque ripple. The stator or rotor can also be skewed to reduce the influence of slot harmonics. However, all these methods have the disadvantage of reducing the fundamental spatial harmonic of the flux density and therefore the mean torque. This paper investigates an alternative approach for synchronous reluctance machines based on analytical equations to reduce torque ripple using additively manufactured rotors and compares them with existing approaches.