Comparison of vector and matrix format tangential interpolation for FDNE

Abstract

Vector format tangential interpolation (VFTI) framework for deriving controllable and observable descriptor state space model using Loewner matrix pencil from the transfer matrix data has been recently proposed for VLSI circuits. It uses data sampled directionally i.e. two columns or two rows of the transfer matrix, called tangential interpolation data. In VFTI the information contained in the frequency samples is not fully utilized and the accuracy gets affected with large number of samples. Matrix format tangential interpolation (MFTI) has been proposed as an enhancement to VFTI in the literature which uses the entire transfer matrix so that all the information contained in the samples is fully utilized. This paper investigates the applicability of MFTI for state space modeling of power system FDNEs and proposes a novel MATLAB® based implementation for Loewner matrix construction. Properties of MFTI such as convergence speed, accuracy, stability and passivity are compared with vector fitting (VF) and VFTI. Impact of number of samples is also studied.