Introduction and Preview

Abstract

The classical state-space model for a proper system, corresponding to a set of ordinary di.erential equations (ODEs), can be obtained by selecting a minimal set of variables (known as state variables). However, there are practical situations where physical variables (referred to as descriptor variables) cannot be chosen as state variables in a natural way to provide a mathematical model in a state-space form. Usually, descriptor variables chosen naturally are not minimal in the sense that they may be related algebraically. This may result in a singular system model since some of the relationships of these variables are dynamic while others purely static.