Calculation and Analysis of Electromagnetic Characteristics of Double-Fed Linear Motor

This paper presents the calculation analysis of the electromagnetic characteristics in double-fed linear motor (DFLM). First, the one-dimensional electromagnetic field model of DFLM is established. In addition, the analytical formulas of airgap magnetic field and average electromagnetic thrust are derived in the condition of full-filled and half-filled endslots DFLM. To elaborate the reason why longitudinal dynamic end effect is neglected, the composition of airgap magnetic flux density is detailedly analyzed. Second, the simulation waveforms of airgap magnetic flux density are obtained by modeling and simulating the short rotor DFLM with ANSYS EM, which are compared with analytical results of linear induction motor (LIM). The analysis results show that the airgap magnetic field of DFLM, unlike LIM, is mainly composed of two fundamental travelling magnetic fields caused by stator and rotor, and the end effect wave has little influence on the magnetic field distortion.