Influences of Magnet Arrangements on Air-Gap Field Modulation Effects in Interior Consequent-Pole PM Machines

Abstract

This article comprehensively investigates and compares the influences of permanent magnet (PM) arrangements on air-gap field modulation effects (AFMEs) in interior consequent-pole PM (ICPM) machines. Four typical single-layer PM structures, i.e., flat-type, spoke-type, U-shaped, and V-shaped magnet designs, are exemplified in order to identify how different rotor structures perform AFMEs due to a double-side slotting and affect the torque behavior. The contributed torque components and corresponding torque proportions of the main air-gap flux density working harmonics are quantificationally distinguished by adopting the Maxwell stress tensor (MST) method. It shows and confirms a fact that the flat-type and V-shaped ICPM cases present the lowest and the highest torque proportions due to their AFMEs, respectively. In addition, the influences of rotor PM parameters on AFMEs of the four single-layer ICPM machines are subsequently studied. Finally, the prototype of the ICPM machine with V-shaped PM structure is manufactured. The corresponding experimental results are conducted to validate the theoretical and finite element (FE) analyses.