Project · Creator and maintainer
Choke AC model fitting
Fitting measured choke impedance to an equivalent circuit a SPICE simulator can use.
Updated
Context
An EMC filter simulation is only as good as the choke model inside it, and a real choke stops behaving like an inductor well below the frequencies the filter is supposed to handle.
Constraint
The datasheet gives an inductance value, not an impedance curve. Without the parasitics, the simulation predicts attenuation the hardware will not deliver.
Contribution
I wrote a MATLAB routine that fits impedance-versus-frequency measurements from an LCR meter to an AC equivalent circuit that drops straight into a SPICE simulation.
Approach
Import helpers read the export formats of the common bench instruments directly, so the measurement reaches the fit without manual reformatting, and the fitted parameters are printed for inspection rather than silently consumed.
Outcome
Filter and converter simulations run on a measured component model instead of a nameplate value.
Evidence
The public repository holds the fitting routine, the impedance model, the instrument import helpers, and sample measurements of three 120 microhenry chokes from different manufacturers.