Parameter Estimation of 2R-1C Circuit Using Embedded Hardware and Measured Impedance Modulus

Abstract

2R-1C equivalent circuit is widely used in electrochemical impedance spectroscopy (EIS), such as modelling of lithium-ion batteries, bioimpedance analysis and water quality monitoring. It allows for an analysis of the basic electrical behavior of electrochemical systems and understanding of the underlying principles. However, the reported parameter estimation methods are usually deployed on the PC-based processing units that limit in-situ and unsupervised applications, where estimation results are free from user inputs. This paper presents a novel methodology for extracting the values of 2R-1C equivalent circuit by solely utilizing the measured impedance modulus. Unlike iterative and PC-based estimation methods, this approach eliminates user inputs in terms of a need for an initial guess, addressing a significant drawback of those approaches. The proposed work was validated by simulated and experimentally obtained impedance. Moreover, details of deployment on the PC-based and embedded hardware were also reported. The utilization of embedded hardware platform (Mega2560) enables an efficient processing of EIS data (80 milliseconds for 100 datapoints) by creating opportunities for in-situ parameter extraction of equivalent electrical circuits.