Torque Contributions of Stator and Rotor PMs in Multi-tooth Dual-PM Machines Accounting for 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 armature pole number and number of split teeth 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 armature pole number and number of split teeth; (b) the torque contribution of rotor PMs is more significant than that of stator PMs in the machines with rotor pole number fewer than stator pole number, and the torque contribution of stator PMs is more significant than that of 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 back-EMF and average torque.