Magnetic field analytical calculation of the permanent magnet synchronous linear motor with fractional slot concentrated windings

In this paper, the multilayer analytical model of a permanent magnet synchronous linear motor with fractional-slot concentrated-winding has been presented. According to the analytical flux density formulas of magnet field derived by the Fourier series, the motor magnetic field generated by winding current and permanent magnet has been analyzed, respectively. Due to the unacceptable calculation inaccuracy of the motor magnetic fields with the traditional method based on the Carter coefficient, the distributed Carter coefficient function has been proposed in order to consider the effect of slotted primary core on the magnetic field. Influences of geometrical parameters such as pole arc coefficient, airgap length, permanent magnet height, and pole slot combination on motor thrust have been analyzed based on the proposed method. The analytical results have been verified by finite element method.