Comparison of Axial Flux Permanent Magnet Synchronous Machines With Electrical Steel Core and Soft Magnetic Composite Core

This paper presents a comparison of axial flux permanent magnet machines (AFPMs) with an electrical steel core and that with a soft magnetic composite (SMC) core. SMCs have several advantages such as low core loss and low eddy current loss. However, compared with electrical steel, SMCs have poor magnetic properties such as low flux density saturation and unsaturated relative permeability. The analysis of the electromagnetic characteristics in a wide frequency range revealed that for an AFPM using an electric steel core, the performance was excellent in a low-frequency range; however, for an AFPM using an SMC core, the performance improves with an increase in frequency. Finally, the operation area of an AFPM using an SMC core is proposed.