Reduction of the Detent Force in a Flux-Switching Permanent Magnet Linear Motor

Abstract

In this paper, the detent force caused by the end effect in a flux-switching permanent magnet linear motor (FSPMLM) with 6 slots and 5 poles is investigated and reduced by two different methods. Firstly, the detent force is diminished by adjusting the position of end teeth of primary side and injecting compensation current into compensation windings wound around the end teeth. Based on the linear relationship between compensation current and compensation force, the proper compensation current is derived and analyzed. Then, to avoid the magnetic coupling between compensation windings and phase windings, a novel compensation module with independent magnet circuit is presented and attached to the primary side of FSPMLM. Thirdly, the two detent force reduction methods are compared with each other, and the compensation module is proved to be more effective. Finally, a prototype of FSPMLM with compensation modules is manufactured and tested to validate the proposed compensation method. Index Terms-Flux-switching linear permanent magnet motor (FSPMLM), detent force, compensation coil, compensation module. I. INTRODUCTIONINEAR MOTORS possess several advantages such as rapid dynamic response, high precision, excellent reliability and quiet operation. Therefore, this kind of motor is greatly required in the occasions where linear motion is needed, such as rail transit, ropeless elevator, and electromagnetic launch [1][2][3][4][5]. However, for the applications demanding extremely long secondary, such as rail transit and ropeless elevator, the conventional permanent magnet linear synchronous motor (PMLSM) is inappropriate, because large amount of expensive permanent magnets or copper windings are indispensable. Flux-switching linear permanent magnet motor (FSPMLM) is more appropriate for the long secondary occasions, because its permanent magnets and windings are all installed in the primary side. Its secondary side only consists Manuscript

A new design approach for reduction of force ripple in permanent magnet flux‐switching linear motor

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A comprehensive analysis on a novel DC‐Excited Flux‐Switching Linear Motor as a new linear vehicle for transportation systems

“…Two compensator windings at both sides of a PM‐FSLM is proposed in Ref. [12] to detent force reduction by analytical equations, and the FEM and experimental results are presented for validation. A six‐phase low‐speed PM‐FSLM for direct‐drive systems is analysed in Ref.…”

“…The FSLMs have two main types, which are investigated by researchers. In the first type, the PM is used for excitation [2,[7][8][9][10][11][12][13][14][15] and in the second, the field winding is employed for DC field production [1,3,[16][17][18][19]. In both the mentioned types, most of the papers are focussed on the structure proposal and characteristic analysis, where the FEM or basic analytical equations are considered for studies.…”

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“…Linear permanent magnet (PM) machines, which can directly produce thrust force without rotary to linear transmission mechanism, are going to replace traditional rotary machines in linear-driven applications, e.g. transportation system, wave energy generation system and ropeless elevator (Cao et al , 2013; Farrok et al , 2018; Huang et al , 2017; Liu et al , 2013; Zhao et al , 2019). Compared with other linear machines, flux-switching permanent magnet (FSPM) linear (FSPML) machines inherit the advantages of linear switched reluctance machines (simple and robust structure) and conventional linear PM machines (high power/force density), having more potential for further research (Gysen et al , 2008; Zhou et al , 2012; Cao et al , 2015).…”