In order to meet the demand of high-power density, high-precision positioning and low cost direct drive system
in ropeless lifting, precision machining and other fields, the modular secondary structure with permanent magnet
synchronous magnetization is adopted in this paper, and the secondary permanent magnet flux-switching
linear machine (SPMFSLM) is proposed. Compared with the traditional primary permanent magnet fluxswitching
linear machine (PPMFSLM), it reduces the thrust ripple and strengthens the primary structure.
According to the topology and operation principle of the machine, starting from the air-gap magnetic field
modulation principle and the convex tooth effect, the contribution of the air-gap flux density harmonics of the
permanent magnet magnetic field and the armature magnetic field for the two machines to the average thrust
is compared and analyzed, reflecting the similarities and differences between the two FSLMs in the thrust generation
mechanism. In addition, the no-load characteristics for back-EMF and the thrust characteristics for
two machines under equal load are calculated and compared. Finally, the multi-objective optimization of the
key structural parameters of the machine is carried out by combining the response surface method (RSM) with
the NSGAII algorithm. Then, the 3D simulation of the machine was carried out and cross-validated with the
2D results. Finally, a double-sided SPMFSLM (DS-SPMFSLM) is proposed from the practical point of view.
The performance of DS-SPMFSLM is significantly superior to that of single-sided SPMFSLM, which verifies
the advantages of the secondary permanent magnet structure scheme.