System reduction using eigen spectrum analysis and Pade approximation technique

A mixed method is proposed for deriving reduced-order models of high-order linear time invariant systems using the combined advantages of eigen spectrum analysis and the Pade approximation technique. The denominator of the reduced-order model is found by eigen spectrum analysis, and the dynamics of the numerator are chosen using the Pade approximation technique. This method guarantees stability of the reduced model if the original high-order system is stable. The method is illustrated by three numerical examples.