Model-order reduction of coupled DAE systems via technique and Krylov subspace method

For a class of coupled systems which include differential-algebraic equation (DAE) subsystems, we discuss model-order reduction (MOR) for them via ε - embedding technique and Krylov subspace method. First we change the coupled system into a closed-loop form. Then, both one-sided and two-sided Arnoldi algorithms are used to reduce the closed-loop system. To preserve the interconnected structure, each subsystems can be reduced by the two same algorithms. Next, we show some facts on the error, stability, and passivity for the resulted systems. Finally, we demonstrate the effectiveness of our approach in two examples.