Analysis of Influence of Rotor Eccentricity in Double Fed Induction Machine

Rotor eccentricity is a common fault in doubly fed induction machines (DFIMs) after long-term operation and bearing aging, which causes uneven air gap thus leading to unbalanced magnetic tension as well as additional vibration and noise. This paper provides a detailed analysis of the impact of rotor eccentricity on the DFIM’s operational performance. The analytical expression of radial electromagnetic force under rotor eccentricity is established, and verified using finite element model. The results indicate that both static and dynamic eccentricity can enrich the harmonic content of radial electromagnetic force, generate odd order force waves, and increase motor vibration and torque ripple. When the eccentricity increases, the indicators are further deteriorate.