Analysis and modeling of modular curved linear permanent magnet motor

The curved PM linear motor is a particular type of linear motor that can satisfy some special utilities. This paper presents an analytical model of the motor based on harmonics analysis. The harmonics of magnetic field induced from PMs and armature windings are obtained using the equivalent MMF source and the slot star, respectively. The effect of the armature slots on the flux distribution is analyzed by equivalent magnetic flux lines in the gap. The relationship between the harmonics of flux density, MMF and magnetic permeance is revealed. Based on the magnetic field analysis, the inductance expressions for the curved PM linear motor are deduced which are useful in improving the design. Comparison of the result of the analytical method and the FEM shows that analytical model has satisfactory precision.