Venkata Sunil Nag currently serves as Assistant Professor at the Department of Electronics and Communication Engineering, Amrita School of Engineering, Coimbatore Campus. He joined Amrita Vishwa Vidyapeetham in the year 2006. He completed his B.Tech in Instrument Technology from University college of Engineering, Andhra University, Andhra Pradesh in 2000 and M.Tech in Electrical Engineering with specialization in Control and instrumentation in 2001 from IIT Delhi. At present he is working towards his PhD at Amrita University. He worked in Bhabha Atomic Research Centre, Trombay as a Scientific Officer from 2002 to 2005 before joining Amrita. His areas of interest are in instrumentation and control and specifically in the area of "fault diagnosis of equipment and processes". He is a member of IETE.

Research Expertise

Application of state estimation techniques for model based fault diagnosis of synchronous generators (Phd area).


Process control, control engineering, digital control systems, industrial automation, network analysis, industrial instrumentation, electrical and electronic measurements, electronics circuits, fibre optics and laser instrumentation, microcontrollers and applications


Publication Type: Journal Article

Year of Conference Title


P. V. Sunil Nag, Silla, G. K., Gummadi, V. H. V., Harishankar, C. B., Ray, V. K., and Dr. Santhosh Kumar C., “Model Based Fault Diagnosis Of Low Earth Orbiting (LEO) Satellite Using Spherical Unscented Kalman Filter”, IFAC-PapersOnLine, vol. 49, pp. 635-638, 2016.[Abstract]

Model based fault detection and diagnosis (FDD) using a non-linear estimation technique is presented here. The non-linear estimation technique namely spherical Unscented Kalman Filter (UKF) has been applied to other kinds of estimation problems but has never been applied to the FDD problem of a Low Earth Orbiting (LEO) satellite. It has been shown in this work that compared to the standard UKF, which is a derivative free estimation technique unlike the popular Extended Kalman Filter (EKF), the spherical UKF can perform better in terms of computational savings without sacrificing accuracy. Hence it is better suited for real-time fault diagnosis. A planar model of the satellite is used to demonstrate the technique. © 2016 IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. More »»


P. V. Sunil Nag, Nair, S. R. P., Gowtham, M., Sibichakravarthy, V., Shivendran, T. D., and Manjunath, S., “Kalman filtering techniques for fault detection and diagnosis in continuously stirred tank reactor (Cstr)”, International Journal of Applied Engineering Research, vol. 10, pp. 37346-37350, 2015.[Abstract]

Fault detection and isolation is one of the major challenges every chemical industry is concerned with, because it deals with the performance of the machinery. Fault detection methods play an essential role in reducing costs, increasing safety and minimizing the effect on the surroundings[1]. To study and compare various Fault detection and isolation techniques, the mathematical model of a continuously stirred tank reactor (CSTR) is implemented in MATLAB. The output, which is obtained from this model, is fed to Kalman filter, which in turn gives a residue that is used to detect the faults present in the system. The difference between the measured process variables and their estimate is called a residue[2]. The same method is used for detecting faults for non-linear state equations with Extended Kalman filter and the residue is obtained from the same. From the residues obtained from Kalman and Extended Kalman filter a conclusion is made that the Extended Kalman filter gives more accurate results. © Research India Publications. More »»


D. Kumar J, .N, H., .S, K., .N, M., S, S., .L, V., and Nag, P. V. Sunil, “Wavelet based Fault Detection for Wind Turbine”, IJCA Proceedings on International Symposium on Devices MEMS, Intelligent Systems & Communication (ISDMISC), pp. 7-10, 2011.[Abstract]

Renewable energy sources are gaining high prominence in today’s world. However, these sources do not supply energy throughout the year and hence efficiency is required when extracting energy from them. Wind energy is a recently developing area of common interest. Efficiency of a wind turbine is however, very low. Hence, detection of fault in the system becomes very essential so as to increase the efficiency. Fault detection is the primary step in FDI (Fault Detection and Isolation) and hence has to be executed using methods giving highest accuracy in predicting the occurrence of a fault. Wavelet transformation is a method which is used to separate the output signal from the faulty signals. Executing wavelet transformation for various sub-systems in the wind turbine, faults in different sub-systems can be detected. Here, we have used a benchmark model for the wind turbine and we have attempted to show how wavelet transform can be used to detect faults. More »»

Publication Type: Conference Proceedings

Year of Conference Title


M. Aravind, Harish, V., B. Sree, L. Sai, Sharma, S., and Nag, P. V. Sunil, “Interfacing and PID control of Liquid Level in a tank using MATLAB”, Proceedings of SARC-ITR International Conference. Chennai, pp. pp. 92-95, 2014.[Abstract]

This paper discusses about control of liquid level in a tank which has an external Yokogawa PID controller UT32A and supports serial communication using RS485 protocol with the PC. The present MODBUS RTU communication via Intouch graphical interface is imitated by opencontrolmodbus serial OPC server and MATLAB (as client). Also, the UT32A controller is replaced by a soft coded PID controller in MATLAB. The open loop curve figures and the PID parameters that are calculated are shown in results which can be further used for fault detection and diagnosis More »»


R. .Sudharma, .Anurudhya, K., .Manoja, M., Taunk, V. H., and Nag, P. V. Sunil, “Controller Design and Graphical User interface Development for a Cascade Level Control System”, Proceedings of SARC-ITR International Conference. Chennai, 2014.[Abstract]

Graphical user interface is a type of user interface that allows user to interact with electronic devices through graphical icons and visual indicators. The actions in GUI are performed through direct manipulations of graphical elements. GUI provides the digital version for users who are not well acquainted with the system. MATLAB is used in the creation of GUI. The proposed scheme includes the interfacing of PID controller with the computer and obtains real time values and displays them. More »»


V. S. Abitha, Jayasankar, V., Divya, A., Joseph, J., and Nag, P. V. Sunil, “Design of PID controller and state observer for flow control system using MATLAB”, Proceedings of SARC-ITR International Conference. Chennai, 2014.[Abstract]

In this paper a scheme for developing PID controller and state observer for a flow control system in MATLAB is proposed. The flow control system is interfaced with MATLAB using OPC toolbox. A digital PID controller is constructed based on position algorithm which enables the user to control the system performance. State space model for the system is developed using System Identification. State observer is constructed in MATLAB by employing the system parameters acquired. The estimation error of the observer should converge to zero to track the system properly. More »»


A. R, M.R., J., J, K. Kumar, V, K., H.K., M., and Nag, P. V. Sunil, “Tuning of fuzzy controller using reinforced sequential search based GA”, ELECTRON - Technical Report of Department of ECE, Special Issue, Proceedings of the First National Conference on Recent Trends in Communication and Signal Processing , vol. 1. pp. pp:246-251, 2009.


P. V. Sunil Nag, V, L., V, M., B, M. Kumar, R, N., and D, V., “Detection and isolation of sensor faults”, Proceedings of the First National Conference on Recent Trends in Communication and Signal Processing (RTCSP’09), vol. 1. pp. pp:252-259, 2009.


J. Mukherjee, Nag, P. V. Sunil, V. Kumar, D., Karmakar, D., and Gantayet, L. M., “Determination of vapour characteristics: Generated by High energy source”, IVSNS-2003. Trombay, Mumbai, 2003.