Analytical Solution of the Magnetic Field in Permanent-Magnet Motors Taking Into Account Slotting Effect: No-Load Vector Potential and Flux Density Calculation

We present a general computation taking into account the slotting effect on the no-load magnetic field distribution in multipole surface mounted permanent-magnet motors (SMPMM). A new analytical solution based on 2-D analysis in polar coordinates is developed. It includes both radial and parallel magnetization and the main originality is to consider the stator slotting. The saturation effect of the magnetic circuit is neglected. The 2-D analytical calculation of the no-load magnetic field with the slotting effect has been validated by a corresponding finite-element analysis (FEA). The analytical results are in very good agreement with those obtained by the FEA, considering both amplitude and waveform.