A Design of Modular Interior Ferrite Magnet Flux-Switching Linear Motor for Track Transport

A novel topology of modular ferrite magnet flux-switching linear motor (FMFSLM) use for track transport is presented in this paper, which enables more ferrite magnets to be inserted into the primary iron core. The motor has a significant low-cost advantage in long-distance linear drive. The proposed FMFSLM's structure and working principle were introduced. Further, the thrust force expression of the motor was established. The thrust force components triggering thrust force ripple were investigated, and their expressions can be obtained according to the inductances' Fourier series expressions. Resultantly, the relationship between the harmonics of thrust force and that of self- and mutual inductances was revealed clearly. Based on the relationship, a skewed secondary should be practical to reduce the thrust force ripple. Thus, the effect of employing a skewed secondary to the proposed FMFSLM was investigated, and an optimized skewing span distance was determined. Finite element analysis (FEA) was conducted to validate the exactness of the theoretical analysis. The simulation results indicate that the strategy of suppressing thrust force ripple has a significant effect. Meanwhile, the motor maintains a good efficiency characteristic. The results of the prototype experiment are in good agreement with FEAs, which further verifies the proposed modular interior FMFSLM's practicability.