No-Load Magnetic Field Prediction of Surface-Mounted Permanent Magnet Machines with a Quasi-Regular Polygon Rotor Core Based on the Conformal Mapping Method

In this article, a new analytical model based on the conformal mapping (CM) method is proposed to address the special construction of surface-mounted permanent magnet (SPM) machines with a quasi-regular polygon rotor core (QPRC). The proposed model divides the upper surface of the QPRC into several segments to ensure that the CM method can deal with this special structure. The equivalent-current method treats PMs as current layers, and the CM method transforms the actual machine into an equivalent regular rectangular model. Then, the no-load air-gap magnetic field can be predicted by solving the complex potential generated by the equivalent currents. Finally, the accuracy of the proposed model can be verified by the finite-element analysis and the experiment.