Two-step order reduction of IC conducted emission models

This paper addresses the order reduction of IC conducted emission models. These models are mathematically described by singular matrices of high order. Usually the order of the matrices can be reduced by the multipoint Krylov based order reduction. To achieve an even lower order we introduce a two step order reduction. The first step is the order reduction method based on the multipoint approximation of system matrices by utilizing the Krylov subspace. The second step is based on the rejection of the dispensable part of a system. To recognize the remaining dispensable system part Lyapunov equations are used. Thus this paper introduces the efficient solutions of the Lyapunov equations. With two-step order reduction a high speed-up in frequency analysis can be achieved.