Hybrid Analysis Method Considering the Axial Flux Leakage in Spoke-Type Permanent Magnet Machines

In this article, a novel hybrid analysis method for spoke-type permanent magnet (PM) machines (STPMMs) is presented, which considers axial flux leakage using the machine's lumped magnetic circuit. The STPMM can increase its air-gap flux density due to its effective flux concentration, but high flux leakage occurs in the axial end of its PMs. This results in a discrepancy between conventional 2-D finite-element analysis results and experimental data. To correct the discrepancy resulting from the unwanted axial flux leakage, a virtual residual flux density of the PM is proposed through equivalent circuits and a finite analysis model. The modified residual flux density is applied to 2-D numerical analyses, and the accuracy and usefulness of the proposed method are confirmed through 3-D numerical analyses.