A Thrust Fluctuation Identification Method for PMLSM Combined with FEA and Least Square

Thrust fluctuation is an important factor which restricts Permanent Magnet Synchronous Linear Motor (PMLSM)’s application in high precision control field. In order to study the thrust fluctuation, a method combining Finite Element Analysis (FEA) and Recursive Least Squares (RLS) is proposed to identify force ripple. Firstly, the finite element model of PMLSM is established. The thrust fluctuation curve is obtained by simulation analysis. Then, spectral analysis is done on the curve, and the main harmonics are obtained, which shows that thrust fluctuation is a periodic function of linear motor pole pitch. Furthermore, data collected on the linear motor test platform is used to identify the fluctuation amplitude with RLS method. Compared with the data measured by sensor, this method has good recognition ability.