MATLAB: Frequency dependent parameters in Simulink

Question

Hi all,

I am a beginner with Simulink and is trying to build a model of an electromagnetic actuator, single-degree-of-freedom-system. The actuator has frequency dependent resistance and inductance (due to induced eddy currents) and also (I believe) frequency dependent damping (due to structural damping in a mechanical spring). My goal is to get the transfer function of the system (force/voltage) in the relevant frequency range 100-10 000Hz. My source is currently a chirp signal.

My question is how can I implement these frequency dependent parameters? I realize that I need to use look-up tables, but I don’t know how to get the current frequency of the signal. Is it possible to use the “invfreqs”-function somehow? Are there any examples of this avaliable?

Thanks in advance for any input on this,

Johan Gustafsson

Answer 1

My suggestion would be to use the System Identification Toolbox to create an estimated mathematical model with your frequency-domain data. You can then use this model in Simulink with the IDMODEL block.

There's an example here of using frequency-domain data to estimate models. This example uses the programmatic approach, but you can also use the GUI approach. See also Supported Models for Frequency-Domain Data.

HTH,

Arnaud