System Identification of an AVR and it’s Control using Finite Dimensional Repetitive Controller

Abstract

This paper presents the application of Finite Dimensional Repetitive Control (FDRC) strategy along with Proportional-Derivative (PD) and Proportional Integral Derivative (PID) controller to an Automatic Voltage Regulator (AVR) for tracking of the periodic reference signal or rejecting periodic disturbances with a known period. In various laboratories and Industrial applications, AVR has mostly used equipment which needs to provide steady regulated output in presence of different fluctuating signals. The whole effort is consist of modeling and order reduction, validated through fitness test with an actual model using standard system identification toolbox, of AVR and development of FDRC. In FDRC, a special type of Repetitive Control (RC), the problem of instability in case of RC occurred due to an infinite number of high-frequency poles, is minimized by introducing a low pass filter in the RC loop which in turn nullifies the effects of high-frequency poles of RC. The developed FDRC system subjected to periodic reference input is applied to reduced order AVR model in the absence of periodic disturbances as well as in the presence of periodic disturbances. Comparative study of conventional controllers and FDRC based PD and PID controller in terms of performances in both time and frequency domains are done to validate the effectiveness of the FDRC over the conventional ideas.