A unified approach for controller reduction in delta domain

A Unified framework for controller reduction in the complex delta domain is presented. The frequency domain method computes the parameters of a low order; easily implementable controller in an approximate Pade' sense by matching the frequency response of the plant cascaded with high order controller. The reduction algorithm is applicable to single-input-single-output (SISO) systems. It further produces a low order discrete-time controller at course sampling frequency and a low order analog controller at high sampling frequency. Example is included to illustrate the usefulness of the method.