A system identification approach to the modelling of pulsed eddy-current systems

The purpose of this article is to present a novel approach in the modelling of pulsed eddy-current systems. Frequency-domain finite element analysis is used to build up a z-domain, finite impulse response (FIR) model. The FIR model allows excitation to be varied without need for the field analysis to be performed again. Furthermore, the proposed approach to the modelling of the system function allows unequal spacing of the frequency samples. This enables greater accuracy of the modelling in the frequency range where the magnitude or phase response of the system varies greatly. The proposed approach was validated on a pulsed remote-field eddy-current system in a ferromagnetic tube. Excellent agreement between predicted and measured response was achieved.