An Improved Sub-Domain Model of Flux Switching Permanent Magnet Machines Considering Harmonic Analysis and Slot Shape

The flux switching permanent magnet motor is a kind of double-salient machine with good speed regulation performances and application prospects. However, in traditional sub-domain models which are used to exactly calculate the magnetic field of the flux switching permanent magnet motor, the orders of major harmonics can not be intuitively obtained. The computational efficiency and practicality of the sub-domain models are limited. Meanwhile, some errors are caused in the equivalent process of iron slot shapes. Aiming at these problems, an improved sub-domain model is proposed in this paper. The major magnetic field harmonics are selected in advance for each sub-domain region by the magnetic permeance function model of the air gap. In addition, the influence of the slot shape equivalence is corrected by the magnetic permeability of slots, and the accuracy of the sub-domain calculation is improved. The proposed model is verified to have the advantages of high accuracy and fast computing speeds by 2-D finite element analysis. A convenient and reliable approach for flux switching permanent magnet motor designs is provided thereby.