Reluctance actuator characterization via FEM simulations and experimental tests

Abstract

Modeling the reluctance of an electromagnetic actuator is a critical step to analyze its dynamics and design model-based controllers. On the one hand, analytical expressions based on either theoretical or empirical models often lack accuracy due to model inconsistencies. On the other, numerical methods are much more precise but require exact information about the system geometry, materials and winding configuration. In this paper we present a new method that brings together the good properties of the finite element method and of system identification techniques to obtain an accurate description of the reluctance and its derivative. Since the method is designed to identify the unknown parameters of the system, it is particularly well suited for modeling existing commercial devices. An application on a safety valve used in gas lines is included to illustrate the method and a discussion on the results shows the advantages of our proposal.

An efficient dynamical model of reluctance actuators with flux fringing and magnetic hysteresis

“…Regardless of the input choice, the dynamic equation has the same structure, φ = f φ (z, φ, H c , u), (18) where the input u can be υ coil or i coil .…”

“…The gap reluctance and its derivative have been previously characterized for different positions from FEM simulations using the geometry presented in Fig. 4b [18]. In order to make use of these data in a dynamical model, the reluctance for any feasible position can be approximated through some type of interpolation.…”

On the Stability of Electromechanical Switching Devices: An Analytic Study of Hysteretic Switching Behaviors

“…A wide variety of methodologies can be found in the literature to obtain such function. Despite the detailed descriptions that can be obtained by numerical methods [29], [30], the nature of the study to be performed makes analytic expressions advantageous in this case. Two different expressions for the reluctance are used in this paper, which in turn result in two different dynamical models for the actuator.…”

Hybrid Dynamical Model for Reluctance Actuators Including Saturation, Hysteresis, and Eddy Currents

“…where R air is the reluctance of the gap which, given that the air is a magnetically linear material, is a function only of z. This reluctance may be obtained by several approaches, but it is highly recommended to use a method that accurately describes the effects of flux fringing [31]. FEM models [2], [14] and analytical expressions [32] are valid options to consider.…”