Accurate time domain extraction of supercapacitor fractional-order model parameters

In this paper we propose using a non-linear least squares fitting process to estimate the impedance parameters of a fractional order model of supercapacitors from their collected step response datasets, without requiring direct measurement of the impedance or frequency response. Experimentally estimated parameters from 1 F supercapacitors verify the proposed time domain method showing less than 2% relative error between the simulated response (using the extracted fractional parameters) and the experimental step response, over the entire dataset.