Electromagnetic Review of Rotor/Stator Misalignment in Permanent Magnet Axial Flux Motor

摘要

This paper presents the findings of a finite element analysis (FEA) investigation into the effect of rotor/stator misalignment on motor performance in a single rotor, dual stator, axial flux electric motor (AFM). Results obtained from the FEA are in good agreement with experimental measurements giving confidence in the use of the model. The results are useful to machine designers who wish to determine the sensitivity of rotor/stator misalignment, due to assembly errors or tolerance stack on machine performance. Axial offset of the rotor in the air gap is found to cause unbalanced axial forces on the rotor of up to 1400 N. The difference in iron loss between stators increased by 17 and 40% at high speed under open- and short-circuit conditions, respectively. Conversely, angular offset between the two stators was found to have little impact on unbalanced rotor forces and iron loss but a relatively large impact on recirculating currents within the machine which lead to uneven heating of the two stators. For an angular offset of 10 elec. deg. a recirculating current of 93 A was found for a phase current of 175 A. Torque ripple was found to decrease from 8 to 6%.