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Numerical Modal Analysis of Vibrations in a Three-Phase Linear Switched Reluctance Actuator

Salvado, J. A. C. ; Calado, M.R.A. ; Santo, A. Espírito ; Guerman, A.

Modelling and Simulation in Engineering Vol., Nº 2017, pp. 1 - 18, April, 2017.

ISSN (print): 1687-5605
ISSN (online): 1687-5591

Scimago Journal Ranking: 0,15 (in 2017)

Digital Object Identifier: 10.1155/2017/3258376

This paper addresses the problem of vibrations produced by switched reluctance actuators, focusing the linear configuration of this type of machines. The primary objective is to characterize the actuator regarding the structural vibrations and to establish the vibration frequencies and the associated mode shapes. The complexity of the mechanical system, the vast number of parts used, and the lack of a priori knowledge puts serious restrictions on the effectiveness of an analytical approach. We build the 3D model of the actuator and use finite element method (FEM) simulation software to find its natural frequencies. The focus is on frequencies within the range up to nearly 1.2 kHz which is considered relevant, based on preliminary simulations and experiments. Spectral analysis results of audio signals from experimental modal excitation are also shown and discussed. The obtained data support the characterization of the linear actuator regarding the excited modes, its vibration frequencies, and mode shapes, with high potential of excitation due to the regular operation regimes of the machine. The results reveal abundant modes and harmonics, and the symmetry characteristics of the actuator, showing that the vibration modes can be excited for a different configuration of the actuator. The identification of the most critical modes is of great significance for the definition of the actuator's control strategies by avoiding excitation regimes that might cause resonances. This analysis also provides significant information to adopt solutions to reduce the vibrations at the design stage of the actuator.