Fallout of the Mover Eccentricity on the PM Eddy Current Loss of Quasi-Halbach T-LSMs

The paper is aimed at an investigation of the effects of the mover eccentricity on the PM eddy current loss of tubular-linear synchronous machines (T-LSMs) equipped with quasi-Halbach magnetized PMs. The study is initiated by an analytical prediction of the no-load spatial repartition of the flux density taking into account the non-coaxiality of the mover and stator, and its validation by a 3D finite element analysis (FEA). Then a special attention is paid to an analytical formulation of the PM eddy current loss in presence of eccentricity. This is achieved considering the case of the radially-magnetized PMs and the axially-magnetized ones. The developed model enables the investigation of the eddy current loss versus the mover eccentricity and the armature magnetic reaction harmonic content range. The obtained results are validated by 3D FEA. This latter is extended to the PM eddy current loss density mapping and loops considering a given range of the armature magnetic reaction harmonic content.