Qualification: 
M.Tech, B-Tech
Email: 
lekshmichandran@am.amrita.edu

Lekshmi R. Chandran currently serves as Assistant Professor in the Department of Electrical and Electronics Engineering at Amrita School of Engineering, Amritapuri. She has completed B. Tech. in EEE from Amrita School of Engineering, Amritapuri in the year 2011 and M. Tech. in Power Electronics from  Amrita School of Engineering in the year 2013. She is currently pursuing Ph.D.

Publications

Publication Type: Journal Article

Year of Publication Title

2021

Lekshmi R. Chandran, Babu, G. S. Ajith, Dr. Manjula G. Nair, and Ilango Karuppasamy, “A review on status monitoring techniques of transformer and a case study on loss of life calculation of distribution transformers”, Materials Today: Proceedings, vol. 46, pp. 4659-4666, 2021.[Abstract]


Transformer failure is one of the main causes of distribution faults. Factors like an inter-winding failure, over current, oil leakage, ambient temperature, electrical faults, etc. are few of the main reasons for transformer failures. In this paper, various monitoring techniques are reviewed along with their advantages and disadvantages so that a proper monitoring technique for various transformer applications can be chosen. A case study is performed on a 500 KVA substation transformer using IEC 60076-7 specified thermal model of transformer. The parameters like top oil temperature and hot-spot temperature are calculated using differential method and exponential method to estimate the loss of life of the transformer and both the methods are compared with one another to decide on the best suited method for calculation of loss of life of the transformer.

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2019

Lekshmi R. Chandran, Ilango Karuppasamy, and Dr. Manjula G. Nair, “Voltage quality enhancement in distribution systems using dynamic voltage restorer with adaptive fuzzy pi controller”, COMPUSOFT: An International Journal of Advanced Computer Technology, vol. 8, 2019.[Abstract]


Distribution of quality power to the consumers is one of the greatest challenges in power industry. In practice, the presence of various nonlinear/sensitive loads disturbs the quality of power supplies in distribution system. Dynamic voltage restorer (DVR) is a custom power device which helps to improve voltage quality in distribution system. In this paper three single phase H-Bridge PWM inverters are used for each phase so as to reduce the voltage rating of the series converters. Synchronous Reference Frame (SRF) theory along with In-phase compensation and Adaptive Fuzzy PI is used as control strategy for DVR. The poor performance by conventional PI controller with fixed gains when the system parameters and operating condition changes is improvised using Adaptive Fuzzy PI controller. The proposed DVR with control strategy is able to improve voltage quality by mitigating voltage sag, voltage swell, phase shift and harmonic problems.

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2015

Lekshmi R. Chandran and Chandran, C., “Analysis Of A Two Switch Buck Boost Ac Dc Converter”, International Conference on Recent Innovations in Engineering and Technology Travanocre College Of Engineering, 2015.

2015

Nandagopal J. L., Lekshmi R. Chandran, R, R., and Vijay, V., “Design and testing of a novel single-stage half-bridge AC-DC converter for battery charging”, The Journal of CPRI, vol. 12, no. 2, 2015.[Abstract]


AC-DC converters are used in most of the electrical utility applications especially in battery charging. Here, a novel topology for single-stage bridgeless ac-dc converter is presented which can give an isolated output voltage and input power factor correction. The input current to an ac-dc converter is rich in low order harmonics and so the total harmonic distortion is high and input power factor is poor. Hence Power Factor Correction (PFC) schemes have been implemented. The effectiveness of the converter is tested and verified in PSIMTM simulation software and in experimental hardware prototype. This topology is found to have reduced losses and better power factor correction compared to the single-stage PFC ac to dc converters with full-bridge diode rectifier. This topology is suitable for battery charging application with reduced losses and better power quality.

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Publication Type: Conference Paper

Year of Publication Title

2020

V. G. Pillai and Lekshmi R. Chandran, “Verdict Prediction for Indian Courts Using Bag of Words and Convolutional Neural Network”, in 2020 Third International Conference on Smart Systems and Inventive Technology (ICSSIT), Tirunelveli, India, 2020.[Abstract]


All courts in India publish judgment by statistically analyzing the data of different cases and understanding the verdict from precedents judgments and the statute law. The approach of our study is to highlight the importance of Convolutional Neural Network (CNN) and Natural Language Processing (NLP) in the legal domain. The Bag of Words technique is being proposed i.e., one of the NLP tool to analyze the text of the court proceedings to extract the keywords from the text and CNN to classify each case into its charges (as per judicial law of India), to predict whether it is a bailable or a non-bailable offence and to give an approximate judicial decision. The results show that this method has an average accuracy of 85% in prediction based on the IPC (Indian Penal Code) which is extracted from the case files. This research work data is taken from the judicial pronouncement and the constitution of India.

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2018

Ajay, Venugopal, P., S, C., Lekshmi R. Chandran, and Krishna, V. D., “Sensor less Speed Control Method for Brushless DC Motors Using Back EMF Method”, in 2018 3rd IEEE International Conference on Recent Trends in Electronics, Information Communication Technology (RTEICT), 2018.[Abstract]


The attributes of a typical BLDC motor consist of high power to weight ratio, high speed, electronic control, high efficiency, low maintenance and silent operation therefore has gained good competence in the current market. The potential of this motor is exercised for most of the industrial applications and automobiles. These motors do not have any brushes for commutation and thus necessities usage of position detecting sensors which would have increased the total cost. To compromise this problem sensorless zero crossing back emf method with PI controller is proposed in this paper. Simulation has been done to verify the proposed scheme. More »»

2017

A. Varghese, Lekshmi R. Chandran, and A. Rajendran, “Power flow control of solar PV based islanded low voltage DC microgrid with battery management system”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


The use of low voltage DC microgrids is a promising concept that makes improvements in power quality and reliability to end users through different control techniques. A coordinated control strategy is addressed within DC microgrid for proper power management between sources and loads and regulation of DC bus voltage. For this; different modes of operation are performed based on state of charge of battery and DC bus voltage. Droop control is an effective solution for power sharing between solar PV; battery and loads. A separate control strategy has been developed for battery charging and discharging. MATLAB/SIMULINK simulation results are presented to demonstrate the effectiveness of the proposed power control strategy with battery management system during various operating conditions. © 2016 IEEE.

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2017

N. Balakrishnan, T. S. Angel, and Lekshmi R. Chandran, “PV-battery system for smart green building using transformer coupled DC-DC converter”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


Power from Solar is absolutely perfect for use with irrigation systems for gardens; allotments; greenhouses and also for supporting the main grid. Since the power generation of PV system is highly depends upon the environmental conditions such as availability of sunlight; atmospheric temperature; wind speed etc. Combining a storage device with PV is one of the viable solutions to deal with the intermittency of renewable energy sources. Conventional methods of combining these components involve multistage converters and single-stage converters. The no of stages and switches increases the overall efficiency of the system decreases. In the conventional system an individual converter is used for maximum power point tracking and also a battery charge controller. These two individual converters are not used in every time. Transformer coupled dual input DC-DC converter is discussed in the system which integrates both the MPPT and battery charging discharging control. A coordinated control is used for making the system to work in four different modes of operation and there by satisfying the efficient MPPT and battery current tracking. The system is simulated and studied under various conditions in MATLAB/Simulink platform. © 2016 IEEE. More »»

2017

C. C. Chandrasekhran, Lekshmi R. Chandran, and A. Rajendran, “Power flow control in low voltage AC microgrid using photovoltaic system and battery energy storage”, in 1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016, 2017.[Abstract]


An ac micro grid mainly consists of distributed generators an energy storage system and loads where the coordinated power management between these elements should be properly done in order to ensure efficient utilization of renewable energy resources. Since the renewable energy sources are inherent sources of supply the energy storage system plays an important role in managing the power flow between each and every elements of the microgrid by keeping the SoC of the ESS under safe region. In this study an autonomous power flow is proposed which is done through bus signaling method and the SoC conditions of ESS. The proposed control algorithm uses local controllers for regulating the bus voltage and frequency of the microgrid. Hence basic power management and voltage and frequency regulation is done within the microgrid. © 2016 IEEE.

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2015

C. Chandran and Lekshmi R. Chandran, “Two Switch Buck Boost converter for Power Factor correction”, in 2015 International Conference on Technological Advancements in Power and Energy (TAP Energy), Kollam, India, 2015.[Abstract]


Now-a-days the usage of power electronic systems has expanded to new and wide application range but the presence of harmonics is a major problem. The nonlinear operation of power semi converters and presence of bridge rectifiers in electronic devices for AC-DC conversion resulted in a high Total Harmonic Distortion (THD) and low Power Factor (PF). Thus there arise the need for a power factor correction circuit along with the power converters for limiting the allowable harmonics on the power lines, and hence to improve the power factor. This paper aims to develop an active power factor correction (PFC) for single phase AC/DC converter, along with a Two Switch Buck- Boost converter. The converter is designed for a load of 1kW at 220V. More »»

2015

S. P. S and Lekshmi R. Chandran, “Bridgeless flyback converter for low power lighting application”, in 2015 International Conference on Technological Advancements in Power and Energy (TAP Energy), Kollam, India, 2015.[Abstract]


Lighting system management and optimization have turned into the most important research trend in lighting electronics. Solar LED lighting scheme is a major kind of light sources in the coming decades because of the efficiency concerns and renewable energy utilization. Conventional LED driving circuit is the combination of diode bridge rectifier and input PFC stage. Diode bridge rectifier at the front end of driving circuit will cause reduced conversion efficiency and power factor. This paper deals with reliable lighting scheme which can be supplied from both solar panel and conventional supply. A battery storage unit is also used to store the energy from PV panel and it also reduces the peak loading while it charging from conventional supply. The dc supply from grid connection is obtained by using bridgeless flyback converter which has inherent power factor correction capability. A MATLAB/Simulink model of proposed scheme is developed for validating the theoretical explanation and the relevant results are also discussed.

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2015

S. P. S and Lekshmi R. Chandran, “Analysis of bidirectional flyback converter”, in International Conference on Computation of Power, Energy, Information and Communication (ICCPEIC), Chennai, India, 2015.[Abstract]


Power converters have great importance in this technically advanced world because many electronic devices use controlled source. Thus new converting topologies are developing to get better operation in terms of efficiency. This paper deals with a bridgeless flyback converter topology which have bidirectional power flow capability. This converter have great importance in the inverters for residential use because, a single converter can be used as AC-DC converter for battery charging and DC-AC conversion while battery discharging. Conventional flyback converter is modified to the proposed bidirectional flyback converter. It is an integration of two flyback converters. The steady state operation and its switching strategy were presented here. Bidirectional flyback converter has been designed with the requirement of 40W, 24 V output in rectification operation and inverting operation aims for the single phase AC voltage of 230V. A battery storage unit is charged by the flyback converter and is discharging through the same converter for the residential AC load, when there is no conventional supply. Matlab/Simulink model has also been developed and relevant results are also discussed in this paper. Simulation results show good correlation with theory. More »»

2015

C. Chandran and Lekshmi R. Chandran, “Performance analysis of Two Switch Buck Boost Converter fed DC motor”, in 2015 International Conference on Computation of Power, Energy, Information and Communication (ICCPEIC), 2015.[Abstract]


This paper deals with the Two Switch Buck-Boost AC-DC converter in CCM mode driving a separately exited dc motor. In order to reduce the risk of damage of motor due to high starting current a three point starter is used in series with the motor. The two switch buck boost converter is controlled in such a way so that the output voltage remains constant despite of variation of the input voltage. Hence the motor is maintained at a constant speed. In this paper a MATLAB/Simulink model of a separately exited dc motor of 5hp, 220V, 16.2A and 1220 rpm driven by a Two Switch Buck Boost Converter has been modeled and simulated. More »»

2015

Lekshmi R. Chandran and S, S. P., “Analysis and PWM control of bridgeless flyback Rectifier”, in International Conference on Recent Innovations in Engineering and Technology Travanocre College Of Engineering, 2015.

2015

J. Freeman, Keerthi, K. Sb, and Lekshmi R. Chandran, “Closed loop control system for a heliostat field”, in Proceedings of IEEE International Conference on Technological Advancements in Power and Energy, TAP Energy 2015, 2015, pp. 272-277.[Abstract]


The alarming energy crisis, heightened by the continuing depletion of fossil fuels, accentuates the need for the development of renewable energy technology, knowledge, and infrastructure. A Central Receiver (Power Tower) Solar Energy system uses heliostats (motorized planar reflectors) to continuously reflect direct radiation from the sun onto a central receiver. This paper discusses a novel closed loop control system for a heliostat field. In this system, rough adjustment of the heliostat is performed using an Inertial Measurement Unit (IMU). Precision adjustment of the heliostat is performed by inducing a small mechanical vibration in the heliostat's reflective surface, using a piezoelectric actuator. This vibration creates time-dependent changes in the light waves reflected from the heliostat, which can be detected by photo-sensors surrounding the thermal receiver target. The position of misaligned heliostats can be corrected once they are identified by FFT analysis of the light waves received by the photo-sensors. This technique can, in principle, control thousands of heliostats simultaneously. The control system is coded using MATLAB. © 2015 IEEE.

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2014

R. Remya, Lekshmi R. Chandran, and Nandagopal J. L., “Design and Simulation of a Single-Stage Half-Bridge AC-DC Converter for Power Factor Correction”, in International Conference On Computation Of Power, Energy, Information and Communication (ICCPEIC), 2014.

2013

Dr. Balamurugan S. and Lekshmi R. Chandran, “Dynamic Voltage Restorer for Voltage Quality Improvement in Distribution System”, in National Conference on Technological Advancements in Power and Energy (TAP Energy), Amrita School of Engineering, Amritapuri, 2013.