Analytical Calculation of No-Load Eletromotive Force and Thrust in Permanent Magnet Linear Synchronous Motors

In view of the complexity of the current magnetic field analytical model of permanent magnet linear synchronous motors (PMLSMs), and in order to improve the computational efficiency of the analytical model, an improved two-dimensional (2D) relative permeance function is used to calculate the no-load eletromotive force(EMF) and thrust of the PMLSM when the slotting effect is considered. The analytical model of slotless PMLSM is established firstly, and an improved 2D relative permeance function is given to solve the tangential relative permeance distribution. According to the analytical model of slotted PMLSM, the normal and tangential magnetic densities are calculated. Based on the analytical model, the no-load EMF and thrust of the PMLSM with different slot-pole combinations are obtained, and the influence of slot-pole combinations, slot width and winding distribution on the electromagnetic parameters is discussed. The accuracy of the analytical method is proved by the finite element method (FEM). Under the condition of accuracy, the proposed method is suitable for the electromagnetic parameter calculation of integral slot and fractional slot PMLSM. It has the characteristics of simple and convenient, low computational burden and good universality, which is conducive to the rapid electromagnetic design and performance optimization of the motor. © 2021, Electrical Technology Press Co. Ltd. All right reserved.