Optimal Current Excitation for the Time-Domain Estimation of the Electrochemical Impedance

Abstract

For the real-time fault detection of electrochemical cells in automotive applications, time-domain based impedance estimation schemes, together with broad-band current excitation signals, have been developed. Whereas the appropriate choice of the estimator is necessary as to prevent a systematic estimation bias, the choice of the applied excitation signal is of equal crucial importance as thereby the covariance of the estimate, and therefore the resulting accuracy of the estimation scheme, is directly influenced. In this work, an optimization of the applied current excitation signal, based on the Fisher information matrix, is proposed and its influence on the estimation accuracy is investigated.