Comparison of electromagnetic performance on E-core axial field flux-switching permanent magnet machines

E-core axial field flux-switching permanent magnet machine (AFFSPMM) is a novel topology. It can be applied in the field of electric and hybrid vehicles because of the short axial size, large torque density and fault tolerance. The filed windings can be wounded around the middle tooth of the E-core topology to carry out the hybrid excitation. In the paper, the E-core topologies with and without field windings are investigated by 3D finite element analysis (FEA). The characteristics of the two topologies are compared, including back-EMF, inductance and torque etc. The FE-predicted results show the torque and fault tolerance in the E-core AFFSPMM without field windings is higher than those in the machine with field windings, while the operation range can be extended in the E-core AFFSPMM with field windings since the field current in the field windings can regulate the flux linkage in each phase windings. Meanwhile, the open-circuit and short-circuit fault is investigated and analyzed by transient analysis. It is also validated that the AFFSPMM without field windings has better fault tolerance.