DESIGN OF DISCRETE CONTROLLERS USING REDUCED ORDER MODELLING

Abstract

Work deals with the design of discrete controller using reduced order modelling.. Any -high order system can be simplified to a lower order system by. using reduced order models such that its transient and steady state behavior remains the same in time domain.. Employing reduced order. , modelling ' for designing • a discrete controller is quite Justifiable able as it makes designing a task of few seconds. It saves the computational labour as well as the accuracy is quite comparable - with that of direct design controller. After transforming . higher order system to lower one, design is done in the s-plane using root locus or • frequency response matching techniques to drive -a - satisfactory controller'. Having designed analog controller, we convert the designs to digital control by considering analog - controller to be filter transfer function and applying any of the conventional techniques to discretize it. Finally we convert the digital controller which is specified in form of ratio of polynomials in z-form or ' a . pulse transfer function to a numerical algorithm . and solve it in real time by digital computer..: