Shape Optimization of Discontinuous Armature Arrangement PMLSM for Reduction of Thrust Ripple

Jun-Hwan Kwon,Euy-Sik Jeon,Jae-Kyung Kim

doi:10.3390/app112211066

Jun-Hwan Kwon, Euy-Sik Jeon + Show 1 more

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https://doi.org/10.3390/app112211066

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Journal: Applied sciences	Publication Date: Nov 22, 2021
License type: CC BY 4.0

Affiliation: Kongju National University

Abstract

The aim of this paper is to present the optimal design process and an optimized model for a discontinuous armature arrangement permanent magnet linear synchronous motor (PMLSM). The stator tooth shapes are optimized to reduce detent force. When the shape of the stator is changed to reduce the detent force, the saturation magnetic flux density and the back electromotive force characteristics change. Multi-objective optimization is used to search for the local lowest point that can improve the detent force, saturation magnetic flux density, and back EMF characteristics. To reduce the detent force generated at the outlet edge, a trapezoidal auxiliary tooth was installed and the performance was analyzed. The experiment’s response surface methodology is used as an optimization method and all the experimental samples are obtained from finite-element analysis. The validity of this method is verified by comparing the optimized FEA model to the initial FEA model.

Highlights

Shape optimization of the armature core was performed to reduce the detent force and back EMF harmonic components that act as thrust ripple in a permanent magnet linear synchronous motor (PMLSM) system with a discontinuous armature arrangement, degrading the operating performance of the system and preventing tooth saturation
Auxiliary teeth in a trapezoidal shape were installed to reduce the detent force generated at the ends of the armature, and an optimal shape was determined for minimizing the detent force
The derived main shape parameters were optimized through the multi-objective optimization based on the response surface methodology (RSM)

Summary

Introduction

A PMLSM with a discontinuous placement of armatures was proposed to address this limitation [3] With such a PMLSM, the quantity of armatures required is reduced, and the material cost and installation time can be minimized; a challenge is that a greater detent force can be generated owing to an increase in the number of ends of the armatures, without the placement of the armatures [4]. The ripple components caused by the detent force may be highly problematic for low-speed driving of the permanent magnet machine and for precise control of the position. The magnet skew, which has been widely used to minimize the cogging force, has been applied to the discontinuous armature arrangement of the PMLSM to reduce the slot and end effects [10].

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