Controller order reduction of large-scale plants using preferred frequency weighted functions

In this paper, the order reduction of both large-scale plant and controller for three approaches in a specified frequency bandwidth of operation are investigated. The three order reduction. approaches are: 1) approximation of a given controller on a closed loop system with preferred frequency weights; 2) synthesis of a controller on a closed loop system using any well known method such as LQG, and then reducing the order of the resulting loop shaped controller; 3) synthesis of a reduced order controller by first reducing the order of the weighted plant model.