Qualification: 
Ph.D
Email: 
manjulagnair@am.amrita.edu

Dr. Manjula G. Nair did her B.Tech in Electrical & Electronics Engineering and M.Tech in Power Systems from the University of Calicut, in 1992 and 2000 respectively. Her M.Tech thesis was on ‘Fuzzy based Control of FACTS devices’. She did her PhD in Power Electronics from the Indian Institute of Technology, Delhi, in 2007. Her dissertation was on ‘Shunt Active Power Filtering for Power Quality Improvement’.

Dr. Manjula G. Nair joined Amrita Institutions in the year 1992 as faculty in Amrita Institute of Computer Technology (AICT), Cochin, Kerala, where she served for a period of two years (1992-93). She joined the Department of Electrical & Electronics Engineering, Amrita School of Engineering, Ettimadai, Coimbatore in 1995 and was with the department till 2008, undertaking teaching and research for B.Tech, M.Tech and Ph.D students. From 2008-2012, she served in the Department of Electrical & Electronics Engineering, Amrita School of Engineering, Bangalore campus, as Professor and later as Chairperson of the department. In October 2012, she moved to Amritapuri campus as Professor in the Department of Electrical & Electronics Engineering.

Manjula Nair has guided several B.Tech and M.Tech research projects. She has also guided two Ph.D students in the area of Electric Power Quality Improvement and Renewable Energy sources. She has to her credit, a three year funded research project under the Young Scientist Fast Track Scheme sponsored by Department of Science & Technology (DST-SERC), Ministry of Human Resource Development (MHRD), Government of India, which she completed in 2012 and another project funded by Amrita, Ettimadai campus, completed in 2008.

She has served as reviewer for research papers in IEEE Transactions in Industrial Electronics and IEEE Transactions in Power Delivery since 2005. She has also served as technical committee member and reviewer for many IEEE international conferences and other international conferences.

Her research interests include Electric Power Quality Analysis & Improvement, Renewable Energy Systems, Grid interconnection Issues of Renewable Energy Systems, Flexible AC Transmission Systems, Fuzzy & ANN controllers, Digital Signal Processing, Signal Processing & analysis of Hindustani and Carnatic musical ragas for Music therapy.

Publications

Publication Type: Conference Paper

Year of Publication Publication Type Title

2017

Conference Paper

P. K. Preetha, S. Babu, S., and Dr. Manjula G. Nair, “DC link voltage regulation in active filter using drainage power from distribution transformer”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


Non-linear loads constitute a major part of loads in the modern industrial and commercial utilities. They inject harmonics to the system and the normal delta-star distribution transformer traps the injected triple-n harmonics in the primary delta winding. This leads to the deterioration and reduction in the life of transformer. Hence, a three winding star-star-delta-utilized transformer is used to trap this harmonic or drainage power in the non-linear power system. This drainage power can be used to power auxiliary loads connected across the tertiary delta winding. Also, drainage power recovery makes the system performance better as triple-n harmonics are eliminated from supply line. For balanced and unbalanced secondary non-linear loads, the tertiary power can be recovered. Also, it can be stored in rechargeable batteries to power regulated loads. In this paper, the use of battery stored drainage power for the voltage regulation in shunt active filters is being discussed. The shunt active filter using Icosφ algorithm provides better harmonic elimination of non-linear load. When a load fluctuation occurs, the dc link capacitor voltage in the filter also fluctuates. Usually, the power needed for voltage regulation is supplied by the grid. In the proposed system, the drainage power stored in the battery is used for the voltage regulation. For using shunt active filter in the YYD-utilized transformer system, the control algorithm of the filter needs to be modified in order to sustain the triple-n harmonics in the system. The power recovered from triple-n harmonics can be stored in a battery and can be further used as the energy storage element of the filter. Results analyzed using MATLAB/SIMULINK reveals that the YYD-utilized system along with shunt active filter gives better utilization of drainage power and the overall system provides harmonic elimination. © 2016 IEEE.

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2017

Conference Paper

V. Raveendran, Krishnan, N. N., and Dr. Manjula G. Nair, “Active power compensation by Smart Park in DC metro railways”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


Smart Park associated shunt active filter has the potential to support the main grid with respect to harmonic, reactive and active power needed by the load. By incorporating modified Icos - controller, active power support capability of Smart Park is studied in accordance with the SOC of master battery and the source current as constraints. The results of simulation prove the effectiveness of active power compensation capability of Smart Park together with harmonic and reactive power compensation for a 750V DC metro traction system. © 2016 IEEE.

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2017

Conference Paper

P.N. Seema, Deepa, V., and Dr. Manjula G. Nair, “Implementation of consumer level intelligence in a smart micro-grid along with HEMS based price prediction scheme”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


The consumer demand is increasing day-by-day with the emergence of new technologies for human comfort. The growing demand is expeditiously leading to the depletion of resources and increasing tariff. The improvised structure of the conventional grid namely, smart grid is rapidly gaining attention with its scheme for efficient meeting of the growing demand and the integration of renewables. The implementation of smart grid requires extensive communication methodology and structured control strategy. In this paper, the controls over the smart grid have been segregated into three as primary, secondary and tertiary. This paper deals with the intelligence associated with the primary and secondary levels placed in regard with the consumer and micro-grid operation. A price prediction scheme as a part of Home Energy Management System (HEMS) has also been designed to increase the consumer awareness. The role of the consumer as well as micro-grid in intelligent demand management has been demonstrated in this paper through simulations in MatLab using fuzzy logic. This system was also verified in hardware and the implementation details have been provided. © 2016 IEEE.

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2016

Conference Paper

Sreelekshmi R.S., Prasad, A., and Dr. Manjula G. Nair, “Control and operation of microgrid connected Hybrid Energy Storage System”, in 2016 International Conference on Energy Efficient Technologies for Sustainability, ICEETS 2016, 2016, pp. 356-360.[Abstract]


The high penetration of the Renewable Energy Sources (RES) can create stability, reliability and power quality problems in the main electrical grid due to their stochastic nature. Microgrids can be analysed as a solution capable of guaranteeing a controlled injection of energy generated by the renewable energy technologies. The use of storage system in a MG plays an essential role in order to ensure energy balance and in maintaining high power quality. Due to the technical limitations of the currently available storage systems, it is necessary to use more than one storage technology to satisfy the requirement of microgrid applications. In order to satisfy the above constraints, this paper proposes the association of a supercapacitor (SC) and a lithium ion battery in a Hybrid Energy Storage System (HESS). A novel control strategy is adopted for the control of the HESS. Hierarchical control is used for the control of the inverter in islanding and grid connected mode. Self synchronization control ensures smooth transition between islanded and grid connected modes. Simulation of the system is carried out in MATLAB/Simulink. More »»

2012

Conference Paper

K. Ilango, Bhargav, A., Trivikram, A., Kavya, P. S., Mounika, G., and Dr. Manjula G. Nair, “Performance Comparison of Shunt Active Filter Interfacing Algorithm for Renewable Energy Sources”, in IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES 2012), Central Power Research Institute (CPRI), Bengaluru, 2012.[Abstract]


The renewable energy source interfacing with grid is the major issue in the electric utility side. The various types of grid interfacing converter topology have been proposed by researchers to improve quality of power and efficiency of the system. This paper focuses the shunt active filter interface for the renewable energy source with an efficient modified IcosΦ algorithm for controlling the grid /source side power flow and renewable energy power with linear static loads. The proposed shunt active filter interfacing algorithm is compared with the well known algorithm of Instantaneous Reactive Power Theory (IRPT) with modifications for reactive power compensation and real power control from the renewable energy source. The performance of the both the algorithms have been simulated and tested in MATLAB/Simulink. More »»

2012

Conference Paper

K. Ilango, Ram, S., and Dr. Manjula G. Nair, “A hybrid photovoltaic-battery powered DC-DC converter with high conversion ratio and reduced switch stress”, in IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES 2012), Central Power Research Institute (CPRI), Bengaluru, 2012.[Abstract]


In this paper, a new hybrid photovoltaic-battery powered DC-DC converter topology is proposed. The proposed topology is realized by cascading buck-boost converter with high step-up converter. High voltage conversion ratio has been achieved using hybrid switched capacitor technique. This proposed topology limits the voltage stress across the semiconductor devices to half of the output voltage. A 400W hybrid photovoltaic-battery powered system with 220V DC output is designed and simulation results have been verified using MATLAB/SIMULINK. More »»

2012

Conference Paper

K. Ilango, P.V., M., and Dr. Manjula G. Nair, “An enhanced controller for shunt active filter interfacing renewable energy source and grid”, in IEEE International Conference on Sustainable Energy Technologies, ICSET, Kathmandu, 2012, pp. 305-310.[Abstract]


Developing efficient interfacing technologies to interconnect renewable energy sources with grid is a promising research area in renewable energy related applications. The interfacing unit becomes crucial as renewable energy sources when directly connected to grid, can inject harmonic components that may deteriorate the quality of power. This paper proposes a mechanism to use shunt active filter as an interface between renewable energy sources and grid with a modified and efficient control scheme. The shunt active filter with this modified controller controls the real power supplied by the grid (source) in addition to its usual functions such as reactive power compensation, power factor correction and harmonic elimination. Performance of the modified IcosΦ controller is compared with that of IRPT control algorithm. Two nonlinear loads are considered here namely AC voltage controller as soft starter for induction motor and a diode bridge rectifier feeding resistive load. Simulation of proposed system proves the effectiveness of using a shunt active filter as the interfacing unit for grid integrated renewable energy systems. ©2012 IEEE.

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2012

Conference Paper

K. Ilango, P.V., M., and Dr. Manjula G. Nair, “An Enhanced Controller for Shunt Active Filter Interfacing Renewable Energy Source and Grid”, in Sustainable Energy Technologies (ICSET), 2012 IEEE Third International Conference on, 2012.[Abstract]


Develoving efficient interfacing technologies to interconnect renewable energy sources with grid is a promising research area in renewable energy related applications. The interfacing unit becomes crucial as renewable energy sources when directly connected to grid, can inject harmonic components that may deteriorate the quality of power. This paper proposes a mechanism to use shunt active filter as an interface between renewable energy sources and grid with a modified and efficient control scheme. The shunt active filter with this modified controller controls the real power supplied by the grid (source) in addition to its usual functions such as reactive power compensation, power factor correction and harmonic elimination. Performance of the modified Icosφ controller is compared with that of IRPT control algorithm. Two nonlinear loads are considered here namely AC voltage controller as soft starter for induction motor and a diode bridge rectifier feeding resistive load. Simulation of proposed system proves the effectiveness of using a shunt active filter as the interfacing unit for grid integrated renewable energy systems.

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2008

Conference Paper

Ga Bhuvaneswari, Charles, Sa, and Dr. Manjula G. Nair, “Power quality studies on a soft-start for an induction motor”, in Transmission and Distribution Exposition Conference: 2008 IEEE PES Powering Toward the Future, PIMS 2008, Chicago, IL, 2008.[Abstract]


Three-phase induction motor of ratings beyond 50 kW take very large low power factor currents while being started directly from a 3-phase supply. Normally soft-starts are used for avoiding this problem and to achieve smooth starting of large capacity induction motors. A 3-phase AC voltage controller is employed as a soft-start. But, this takes harmonic-rich current especially while operating at large firing angles. In this paper, the effect of inserting a shunt active filter to provide harmonic and reactive power compensation in a soft-start has been studied. The shunt active filter has been inserted between the AC voltage controller and power supply to take care of the reactive power requirement of the motor and AC voltage controller and also to provide harmonic compensation. Both simulation hardware studies have been done on a 22 kW induction motor with and without soft-start arrangement. The shunt-active filter uses the IcosΦ control algorithm for calculating the compensation currents. The results with the insertion of shunt active filter show a substantial reduction in the current drawn from the source and its harmonic content. This will be a very useful scheme especially in industries where multiple induction motors of large capacity are frequently started from a 3-phase supply. ©2008 IEEE.

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2008

Conference Paper

M. R. Sindhu, Dr. Manjula G. Nair, and Nambiar, T. N. P., “An ANN based digital controller for a three-phase active power filter”, in 2008 Joint International Conference on Power System Technology POWERCON and IEEE Power India Conference, POWERCON 2008, New Delhi, 2008.[Abstract]


Three-phase shunt active power filters are designed to effectively compensate for the current harmonics and reactive power requirements in a three-phase system with harmonic loads. An ANN (artificial neural network) based controller selects the amount of harmonic current injection based on the percentage of harmonic distortion present in the source current and also on the reactive power requirement of the load. The selection is done by the ANN with the help of a properly tuned knowledge base. © 2008 IEEE. More »»

2002

Conference Paper

Dr. Manjula G. Nair and Nambiar, T. N. P., “Fuzzy logic based facts controller for damping oscillations”, in Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference, Yokahama, 2002, vol. 3, pp. 2019-2022.[Abstract]


This paper describes the modeling and fuzzy based control to enhance the dynamic stability of a single machine connected to a large system through flexible ac transmission system. A linear model of a synchronous machine with excitation system characterized by a single time constant and gain is adopted for this purpose. The synchronous machine is described in terms of six parameters derived on the basis of operating conditions and line reactance. The flexible ac transmission system adjusts the line reactance by turning on/off series capacitance added to the transmission line. The effect of change in line reactance on the parameter values of the machine model is found and the most sensitive parameters are identified. The response of the machine for different disturbances and natural damping coefficients is evaluated by modifying the most sensitive parameters using the fuzzy knowledge-based FACTS controller. The simulation studies bring out the effectiveness of the control scheme. More »»

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