RL-Ladder Circuit Models for Eddy-Current Problems With Translational Movement

This article proposes an adaptive equivalent
$RL$
-circuit model for eddy-current devices with a single electrical port (one terminal voltage and current) and translational movement. The device is first characterized by means of frequency-domain finite-element computations in the relevant frequency and position intervals, for subsequently fitting constant-coefficient
$RL$
-ladder circuits of adjustable size (i.e., variable number of branches and loops). The accuracy of the ladder-circuit model is assessed in both the frequency and time domains. The time-varying position involves the force computation from the circuit and the coupling with the mechanical equation. By way of validation, we study the axisymmetric magnetic-levitation device of TEAM Workshop problem 28. Results exhibit good convergence to reference finite-element ones with increasing number of branches.