Order reduction by error minimization technique

Modeling physical systems usually results in system of higher order whose order is greater than two. It is often desirable to approximate these models by reduced order models. A computationally simple approach is proposed for order reduction of linear time invariant discrete systems. The reduced order model is obtained by using the stability equation method and where the reduced order denominator polynomial constant term is obtained from the original higher order system transfer function. The proposed method assures the stability of the system under the reduced order model case. The validity of the proposed method is illustrated by solving few numerical examples and the results are compared with the existing techniques.