U. Kim et Dk. Lieu, MAGNETIC-FIELD CALCULATION IN PERMANENT-MAGNET MOTORS WITH ROTOR ECCENTRICITY - WITHOUT SLOTTING EFFECT, IEEE transactions on magnetics, 34(4), 1998, pp. 2243-2252
An analytical technique for predicting the instantaneous magnetic held
distribution in the air gap region of permanent magnet motors with ro
tor eccentricity is developed, The governing equations and associated
boundary conditions are formulated and solved by a perturbation method
. The predicted solutions are verified by the results of a correspondi
ng finite element analysis. The results show the effectiveness of usin
g the perturbation method for this eccentric field calculation, Accord
ing to this study, the additional flux density due to rotor eccentrici
ty is proportional to the amount of the eccentricity in a small range
and has a quite different distribution from the normal flux density wi
thout rotor eccentricity, Accordingly, rotor eccentricity mag cause un
desirable effects on brushless permanent magnet motors.