Investigation on Winding Theory for Short Primary Linear Machines

The winding theory is a crucial tool for analyzing the electric machines. However, some special phenomena in short primary linear machines (SPLMs) cannot be explained by the traditional theory, which is commonly applied in rotary machines (RMs). In this paper, an improved winding theory for SPLMs is presented. Starting with the magnetic field produced by a single conductor, the difference between winding theory for SPLMs and RMs is analyzed. According to the proposed theory, the pulsating magneto-motive force (MMF) and the asymmetry of the three-phase windings can be analyzed and calculated in details. It is very useful for perceiving, analysis and optimal design for the winding in SPLMs. The proposed theory is verified by 2-D finite-element analysis (FEA) and experiment.