Identification of the fractional impedance of ultracapacitors

Abstract

Ultracapacitor are devices used to store energy in which diffusion phenomena are important. This paper obtains an identification of a double layer ultracapacitor using impedance spectroscopy. It has been observed from experimental data, that the ultracapacitor has a fractional behaviour. In order to get a good accuracy, conventional models use a lot of parameters. This paper proposes the two novel methods modelling ultracapacitors in the frequency domain, based on the fractional calculus with a few parameters. Copyright © 2006 IFAC.