Air-Gap Flux Density Characteristics of Salient Pole Synchronous Permanent-Magnet Machines

The detailed knowledge of the field distribution in the air gap is of main importance for predicting and optimizing the performance of electric machines. In this paper, the air-gap flux density of a salient pole permanent-magnet (PM) synchronous machines is determined and investigated using a new analytical model. The stator slotting and rotor saliency effect, and also the air-gap MMF harmonics are considered. Different no-load and under load simulations are performed to show the permeance effect (rotor saliency and stator slotting) on the air-gap flux density characteristics of this type of machine. The simulations results show that as results of the permeance harmonics additional harmonics are induced on the air-gap flux density and these harmonics are very sensitive on the rotor pole shape parameters. Furthermore, the time domain analysis shows also that the permeance harmonics leads to the fluctuation of the resulting air-gap flux density harmonics with the time.