Influence of Variation of Recoil Permeability of Bonded Magnets on Demagnetization Characteristics of Permanent Magnet Assisted Synchronous Reluctance Motor

Demagnetization analysis is complicated in the case of motors with bonded magnets, which have unique B-H curves and do not exhibit clear knee points. We have proposed a permanent magnet assisted synchronous motor (PMASynRM) containing bonded magnets, and examined its demagnetization characteristics in the case where the recoil relative permeability (µ
rec
) was assumed to be constant. However, µ
rec
in fact depends on the reverse magnetic field from the stator and the temperature. This study therefore investigates the irreversible demagnetization characteristics of a PMASynRM taking the variation of µ
rec
for the bonded magnets into account. The analysis results are compared to those when µ
rec
is assumed to be constant. The results indicate that there is no problem with assuming a constant µ
rec
of 1.15 and an analysis model having mainly the reluctance torque.