Development of impedance analysis software implementing a support function to find good initial guess using an interactive graphical user interface

Abstract

We developed an impedance analysis software implementing new function for finding an appropriate initial parameter set for impedance spectrum analysis using an interactive graphical user interface (GUI). This new function can be applied without limitation of the equivalent circuits on the basis of a measurement model. The initial parameter values of an equivalent circuit model, which is represented by a peculiar script, can easily be obtained by selecting a data point using a cursor on the logarithm of frequency versus imaginary part of impedance plot by GUI operation and setting a partial impedance element on the graphic control panel. The partial impedance elements include a resistor, capacitor, inductor, a resistor parallelly connected to a capacitor, Warburg impedance, Gerischer impedance, and Havriliak-Negami impedance. Calculating and setting the initial values of the parameters are performed through GUI control, that is, by simply dragging a cursor and clicking buttons. On the basis of this GUI function, users can easily avoid the divergence of complex nonlinear least square process because the calculation can start from an adequate initial guess.