Research rticle Design and Robustness Analysis of Multiple Extended State Observer Based Controller (MESOBC) for AVR of the Power System Ravi Gandhi, 1 S. B. Masikana, 2 Gulshan Sharma , 3 and Emre Çelik 4 1 School of Engineering, jeenkya DY Patil University, Pune 412105, India 2 Department of Electrical Engineering, Mangosuthu University of Technology, Durban & Department of Electrical Engineering Technology, University of Johannesburg, Johannesburg 2006, South frica 3 Department of Electrical Engineering Technology, University of Johannesburg, Johannesburg 2006, South frica 4 Department of Electrical and Electronics Engineering, Engineering Faculty, D¨ uzce University, D¨ uzce, Turkey Correspondence should be addressed to Gulshan Sharma; gulshanmail2005@gmail.com Received 25 September 2022; Revised 30 October 2022; Accepted 1 March 2023; Published 10 March 2023 Academic Editor: Ramesh Chand Bansal Copyright © 2023 Ravi Gandhi et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Automatic voltage regulator (AVR) is installed on the synchronous generators in the power system and plays a very important role in maintaining the generator output voltage besides changes in load demand, parametric uncertainties, and operating tem• perature. As the load is continuously varying in the system, the AVR needs controllers to track and regulate the voltage of the synchronous generator much faster. Tis paper shows an initial attempt to design a robust multiple extended state observer (MESO) to estimate the variation in lump disturbances (i.e., load demand and parametric uncertainties) from all the components of the AVR. MESO•based controller (MESOBC) can track such matching and mismatching of both types of irregularities and regulate the terminal voltage of the generator accordingly. MESOBC performance is matched with strong published AVR designs for a standard condition, ±30% load voltage variation and for simultaneous changes in AVR parameters with ±30% load voltage variations. Integrated square error (ISE) is chosen as an objective function to compare the output of MESOBC with other published AVR designs in view of graphical AVR responses and by calculating various numerical values for AVR responses. At last, the robustness of MESOBC is also checked through sensitivity analysis, and it is seen that MESOBC guaranteed robust performance for the AVR of the power system under diverse operating conditions. 1.Introduction Te modern power system is complex and getting wider and wider these days to meet the continuous electrical energy demands of the society and nation. Any successful power system needs to maintain the voltage and frequency of the power system very tightly to its nominal value. However, due to the shifting of consumers’ electrical energy demands, it is very difcult to maintain these electrical parameters, and ultimately it results in the insufciency of the power system to deliver quality electrical energy to various customers. Te AVR is a feedback control system which measures the current synchronous generator output voltage and matched it with the reference voltage value, and hence an error signal is generated. Tis error signal is used to manage the exci• tation of the synchronous generator, and thus the AVR can increase or decrease the generator output voltage consid• ering that voltage should be within its tight band as per the system requirements. However, synchronous generator output voltage shows a very slow response due to varying load and high alternator feld windingsinductance [1]. Hence, a controller is a must for the AVR of the power system to achieve a faster response with minimum over• shoot, reduced settling time, and zero steady•state error for various disturbances. Various types of controllers such as PID, PID with acceleration (PID•A), fractional order de• veloped PID, and controllers built on various concepts of fuzzy logic are available for the AVR in [2–6]. Recently, Hindawi International Transactions on Electrical Energy Systems Volume 2023, Article ID 1869840, 15 pages https://doi.org/10.1155/2023/1869840