Algebraic characterizations for positive realness of descriptor systems

Abstract

In this paper, algebraic characterizations for the positive realness of descriptor systems are studied. It is shown that the positive realness of descriptor systems can be determined by solving a linear matrix inequality, and hence the celebrated positive real lemma for standard state space systems is extended to descriptor systems. In addition, the lossless positive realness of both standard state space systems and descriptor systems is characterized explicitly based on the controllable staircase forms of standard state space systems and the generalized controllable staircase forms of descriptor systems, respectively. © 2008 Society for Industrial and Applied Mathematics.