| In this paper, the multilayer analytical model of the permanent magnet synchronous linear motor with fractional slot concentrated windings has been presented based on the expressions of winding current distribution and the body current density equivalence of permanent magnet. The variation of magnet field in z direction has been neglected. The analytical expression of magnetic field distribution has been abstained through solving the Passions equation and Laplace equation in different field by the method of variables separation and Fourier series. According to the analytical flux density formulas of airgap field and permanent magnet field derived by the Fourier series, the motor magnetic fields generated by winding current and permanent magnet have been analyzed, respectively. Due to the unacceptable calculation inaccuracy of FSCW-PMSLM 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. And the calculation results have been improved comparing with the traditional method.Based on the already obtained magnet field distribution expressions, the influences of structural parameters such as pole arc coefficient, height of permanent magnet, pole-slot combination and airgap length on the motor thrust have been analyzed. The accuracy of the presented analytical method has been verified by finite element method. The thermal field of the motor has also been researched, all of which can provide preferences for magnetic field calculation and optimization of the FSCW-PMSLM. |
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