End Force Modeling and Modular-Secondary Optimization of Long-Secondary Permanent Magnet Linear Synchronous Motor

The modular and long secondary permanent magnet linear synchronous motor (PMLSM) is applied to logistics and industrial production lines because its stroke and trajectory can be flexibly adjusted. However, the modular-secondary (MS) structure leads to a great fluctuation of detent force with different fluctuation characteristics from continuous-secondary (CS) structure. When the primary structure is determined, optimizing the MS structure can solve this problem. Based on the different combinations of primary and unit-secondary (US), the laws of harmonic distributions of single-end end force are obtained. Based on this, single-end end force's piecewise function model is established to obtain the variation rules of end force amplitudes, which reflect the variation trend and period of different sub-harmonic amplitude values of detent force. Further, it reflects the variation curve of the peak-to-peak values of detent force and gives the best value point of spacing between US. This is a simple and convenient method for optimizing the MS structure and suppressing the detent force without changing primary structure. The theoretical analysis is also verified by the experiments of single-end end force and detent force.