IMPROVED MODAL TRUNCATION APPROXIMANT: A HYBRID APPROACH

Abstract

A hybrid method using modal truncation and singular perturbation to derive the reduced order model for a stable higher order system is presented. The approach is based on retaining the dominant modes of the system and truncating comparatively the less significant once. As the reduced order model has been derived from retaining the dominant modes of the original high order stable system, the reduced order model preserves the stability. The strong demerit of the modal truncation method is that, the steady state value of the reduced model does not match with the original system. This demerit has been overcome by applying singular perturbation approach of the balanced truncation method. Results obtained show the effectiveness of the proposed technique. Numerical examples are carried out to illustrate the procedure. Further it has been also applied to a system of order 1006 to check its applicability to large scale systems as well.