An Accurate No-Load Analytical Model of Flat Linear Permanent Magnet Synchronous Machine Accounting for End Effects

Abstract

This article proposes an improved analytical model of slotted linear permanent magnet synchronous machines (LPMSMs) to fast and accurately obtain the magnetic field distribution and detent force. Considering the secondary end effect can optimize the thrust performance in terms of machine control, while there are few research works focusing on this study. Combined with the periodic extension method, both the primary and secondary end effects are taken into consideration, which is the major contribution of this article. The analytical model containing seven subdomains (SDs) is conducted in Cartesian coordinates. The magnetic distributions in air-gap, slots, and end regions are obtained by solving Maxwell equations with various interface conditions. The thrust and normal forces are subsequently calculated based on the Maxwell stress tensor. The corresponding finite element (FE) model produces numerical results to validate the analytical results. A prototype is manufactured and tested. The experimental results show that the improved analytical model is accurate and efficient in no-load performance calculation. The investigation shows that this proposed method can be applied to all of the LPMSMs with similar structures.