Contributions of Stator and Rotor PMs in Torque Production of Multi-Tooth Dual-PM Machines With Different Stator/Rotor Pole Number Combinations

This paper investigates the torque contributions of stator and rotor permanent magnets (PMs) in multi-tooth dual-PM machines accounting for stator/rotor pole number combinations. The influences of different total PM volume constraints during optimisation, armature pole number, split tooth number, and key parameters are also considered. It is found that (a) the significance of torque contributions of stator and rotor PMs is dictated by the relationship between stator pole number and rotor pole number, but is not affected by different total PM volume constraints during optimisation, armature pole number, split tooth number, and key parameters; (b) rotor PMs have a more significant torque contribution than stator PMs in the machines with fewer rotor pole number than stator pole number, and stator PMs have a more significant torque contribution than rotor PMs in the machines with fewer stator pole number than rotor pole number; (c) the multi-tooth dual-PM machines with fewer rotor pole number than stator pole number can generate higher average torque. Two prototypes are built and tested to validate the FEA results and analyses.