Analysis of Field Modulation Effect in Consequent Pole Permanent Magnet Machines with Concentrated Windings

In this paper, the torque production mechanism of consequent pole permanent magnet (CPPM) machines is analyzed from the perspective of field modulation effect (FME). In order to reveal the working harmonics in CPPM machines, a simplified permeance model is established accounting for stator slotting effect. The Maxwell stress tensor method is utilized to provide the insight of the effective harmonics contributing to the torque production in CPPM machines. Based on the finite element (FE) method, four CPPM and four surface-PM (SPM) machines with different rotor pole pairs and single- or double-layer concentrated windings, are analyzed and compared. It is shown that the FME in CPPM machines contributes more the electromagnetic torque than its SPM counterparts.