Generation of State Equations for Circuits with Excess Elements

In this paper is presented a procedure able to obtain the state equations in normal form for electrical circuits, for both cases of circuits with and without excess elements. The method starts from the symbolic hybrid representation of the circuit, previously developed by the authors for circuits without excess elements. The symbolic state matrix is very useful for example during LR iterations which compute the approximate expressions of poles and zeros. To illustrate this approach, three examples of circuits with excess elements are given, one containing an inductor cut-set, one containing a capacitor loop, and one containing both an inductor cut-set and a capacitor loop.