A New Technique for the Reduced-Order Modelling of Linear Dynamic Systems and Design of Controller

In this article, a new system diminution technique is proposed for the reduction in complexity and controller design of the higher-order models. This method is based on the Mihailov stability method which ensures the stability of the obtained simplified/micro-model if the higher-order plant is stable. In this technique, the reduced characteristic equation of the simplified plant is obtained by using the Mihailov stability technique and the reduced numerator equation is determined by using the improved Padé approximation technique. By using this reduced-order model, the PID controller is designed for the large-scale system. The accuracy and effectiveness of the proposed method are validated by comparing the step responses of the complete and lower-order models. The performance of the recommended technique is shown in terms of step responses and performance error indices. Three standard numerical systems are finally provided to validate the effectiveness and accuracy of the designed controller and the performance of the proposed model-order reduction technique.