Mixed complete Padé model reduction: a useful formulation for closed loop design

A simple formulation for derivation of reduced order models for linear time invariant systems by mixed complete Padé approximation is presented. Various reduced order models of the same order with different combinations of the number of matched Markov parameters and time moments can be derived by equations that resemble the simple Padé equations for approximation at a single point. The advantages of obtaining models by a complete Padé approximation is emphasised.