Feature Investigation of a Segmented Pole Quasi- <italic>Halbach</italic> Tubular-Linear Synchronous Machine

Abstract

The paper is aimed at an investigation of the features of a tubular-linear synchronous quasi-Halbach machine (T-LSM) where the radially-magnetized PMs are substituted by four equal segments with parallel magnetization. This substitution is done in an attempt to improve the machine cost-effectiveness which makes it a viable candidate to equip free-piston engine-based series hybrid propulsion systems. The study is initiated by an analytical formulation of the air gap flux density considering (i) the case of the conventional quasi-Halbach T-LSM and (ii) the case of the segmented pole one. The comparison between the two T-LSMs is extended to a 3D finite element analysis (FEA)-based investigation of their no- and on-load features. Following the prototyping of the quasi-Halbach T-LSM with segmented poles, selected features predicted by 3D FEA are experimentally-validated. It is shown that while the PM segmentation slightly affects the machine back-EMF and cogging force, it has a remarkable fallout on its force production capability which makes it necessary the assessment of the cost-performance trade-off.

Keywords

• Halbach PM tubular-linear synchronous machine%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> Quasi-<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Halbach</italic> PM tubular-linear synchronous machine
• segmented poles
• analytical model
• 3D finite element analysis
• no- and on-load features
• cost-performance trade-off