Modeling and flux leakage analysis for long-stator PM linear motor including longitudinal end effects

The main advantages of long-stator permanent magnet (PM) linear motor are light mover and fixed cables. But it has longitudinal end effects, which causes uneven airgap magnetic field distribution. The equivalent magnetic circuit model in long-stator linear motor differs from that in rotary and short-stator counterparts. The purpose of this paper is to establish accurate equivalent magnetic circuit model including longitudinal end effects for long-stator PM linear motor. The free parameter representing uneven flux conditions is introduced in the model. Further, flux leakage coefficients are calculated and compared by proposed model and electromagnetic fields analysis. Finally the revised mathematical expression of unload electromotive force (EMF) are presented and experiment validate the accuracy of analysis results.