Model reduction for descriptor system

A model reduction method to match the coefficient of the transfer function G(s) of descriptor system is presented to obtain reduced order descriptor system. By projecting G(s) to the transfer function of discrete time system, the model reduction problem for the descriptor system is transformed to Markov parameters matching model reduction problem of the corresponding discrete time normal systems. The impulse structure is preserved in the model reduction procedure. A numerical example is provided to demonstrate the effectiveness of the proposed method.