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Search Results: 1 - 10 of 143 matches for " Seyezhai Ramalingam "
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Comparative Analysis of Analog and Digital Controllers for Negative Output Superlift Luo Converter (NOSLC)  [PDF]
Chamundeeswari Vinayagam, Seyezhai Ramalingam
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.78146
Abstract: This paper focuses on the comparative study of analog and digital control techniques for Negative Output Superlift Luo converter (NOSLC). NOSLC is a high gain converter in which the positive source voltage is converted into a negative load voltage. Though the negative load voltage is produced effectively, there is lot of non-linearities that affects the voltage level. To overcome this, analog controllers like Proportional-integral (PI), fuzzy PI and a sliding mode controller (SMC) were proposed for NOSLC. However PI controller does not respond to changes in operating point, fuzzy PI is based on the systematic approach and proved to be a trial and error oriented method and SMC brings an oscillation in the duty cycle. Therefore, to overcome these drawbacks, a digital control technique using PIC microcontroller is proposed in this paper which provides high versatility and programmability approach. Simulation studies are carried out in MATLAB and the performances of these controllers have been investigated for the proposed DC-DC converter. A prototype of the NOSLC converter is built by employing digital control and the results are verified experimentally.
Modeling and Analysis of Variable Frequency Inverted Sine PWM Technique for a Hybrid Cascaded Multilevel Inverter  [PDF]
M. Sudhakaran, R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79228
Abstract: In cascaded H-bridge multilevel inverter, a variable frequency inverted sine PWM technique is modeled for hybrid electric vehicles. It has a particular advantage of increasing power which is achieved using series connection of H-bridge and also this topology is capable to produce superior spectral quality with considerable improvement of fundamental voltage. The variable frequency inverted sine PWM technique produces lesser torque ripple and enhances the fundamental output voltage mainly at lower modulation index ranges. The topologies of multilevel inverter are flying capacitor, diode clamped and cascaded inverter. In the paper, we will discuss about the cascaded multilevel inverter based on inverted sine PWM technique. The two switching strategies widely used to control multilevel inverters are constant frequency inverted sine PWM (CF-ISPWM) and variable frequency inverted sine PWM (VF-ISPWM). This implies that switch utilization substantially reduces 32.35% of the constant frequency inverted sine PWM switching technique. The performance of the technique is validated in terms of Total Harmonic Distortion (THD) and Torque ripple which significantly reduces when compared to constant frequency ISPWM. The analysis of conventional triangular PWM inverter and inverted sine PWM inverter using constant and variable switching scheme is done in MATLAB Simulink and verified experimentally by FPGA Spartan 3E processor.
Design and Experimentation of FPGA-Based Soft-Switched Interleaved Boost Converter for Telecommunication System  [PDF]
? Chitravalavan, Dr. R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79233
Abstract: This paper proposes the design and experimentation of digital control of soft-switched interleaved boost converter using FPGA for Telecommunication System. The switching devices in the proposed converter are turned on and off with Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS) respectively. The circuit is operated in Continuous Conduction Mode (CCM) with various load ranges having duty cycle of more than 50%. The proposed converter is studied by developing the simulation module in MATLAB/SIMULINK. A PI controller is designed and implemented in FPGA to obtain a regulated DC output for line and load variations. Simulation and experimentation results are verified with a prototype development of the proposed converter. The results indicate that the converter performance is enhanced with closed loop control.
Modified Diode Assisted Extended Boost Quasi Z-Source Inverter for PV Applications  [PDF]
N. Hemalatha, R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.710279
Abstract: Thedesign, simulation and implementation of modified diode assisted extended boost q-ZSI(MDAEB q-ZSI) for photovoltaic application are proposed in this paper. It is the most efficient topology that provides a single stage conversion for PV systems by providing high input voltage gain, reduced number of components count, increased voltage boost property, reduced voltage ratings, reduced voltage stress across the switches and simplified control strategies. Its unique capability in single stage conversion with improved voltage gain is used for voltage buck and boost function. The operating modes and the steady statetheoretical analysis of voltage boost, control methods and a system design guide for the proposed topology are investigated in this paper. A simulation model of the PV system based on MDAEB q-ZSI has been built in MATLAB/ SIMULINK. Performance parameters such as Total harmonic distortion (THD), voltage gain, voltage stress and boost factor are computed and compared with the conventional quasi z-source inverter. The prototype model for MDAEB q-ZSI is developed and the results are validated.
Investigation of Current Control Techniques of AC-DC Interleaved Boost PFC Converter  [PDF]
A. Inba Rexy, R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.74027
Abstract: This paper presents the comparison of various current control strategies employed for an interleaved power factor correction (PFC) boost converter for improving the power quality. The major control strategies discussed in this paper are: peak current control, average current control, hysteresis control, borderline current control and non-linear control. These strategies are implemented in MATLAB/SIMULINK and the performance of the proposed converter is compared under open loop and closed loop operation. From the results, the input current waveform was close to input voltage waveform implying improved power factor and reduced total harmonic distortion for nonlinear current control technique. Experimental results validate the proposed method.
Simulation and Implementation of Solar Powered Electric Vehicle  [PDF]
A. Bharathi Sankar, R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76055
Abstract: The rise in the price of oil and pollution issues has increased the interest on the development of electric vehicles. This paper discusses about the application of solar energy to power up the vehicle. The basic principle of solar based electric vehicle is to use energy that is stored in a battery to drive the motor and it moves the vehicle in forward or reverse direction. The Photo Voltaic (PV) module may be connected either in parallel or series, and the charge controllers direct this solar power to the batteries. The DC voltage from the PV panel is then boosted up using a boost DC-DC converter, and then an inverter, where DC power is converted to AC power, ultimately runs the Brushless DC motor which is used as the drive motor for the vehicle application. This paper focuses on the design, simulation and implementation of the various components, namely: solar panel, charge controller, battery, DC-DC boost converter, DC-AC power converter (inverter circuit) and BLDC motor for the vehicle application. All these components are modeled in MATLAB/SIMULINK and in real-time, the hardware integration of the system is developed and tested to verify the simulation results.
An Approach towards Pulse Data Transmission Using Modified Negative Luo Converter (MNLC) for Telecoms  [PDF]
V. Chamundeeswari, Dr. R. Seyezhai
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79234
Abstract: Telecom sectors generally operate at negative voltages to reduce the effect of corrosion caused in the metallic wire due to electrochemical reaction while communicating signals. To feed those lines and to have an effective digital data transmission, a power electronic converter referred as Modified Negative Luo Converter (MNLC) is proposed in this paper. MNLC is a high gain converter in which the output voltage increases in geometric progression. This paper portrays a novel concept of a 50 Hz pulse data transmission throughRLCG (Resistance-inductance-capacitance with a shunt conductance) transmission line using MNLC. Signal frequency of 50 Hz to be transmitted is anded with a high frequency pulse that charges and discharges MNLC and produces the boosted negative output voltage. The boosted output is again transmitted through the RLCG transmission line from which 50 Hz data pulse is retrieved at the output of the transmission line by comparing with a comparator signal. This sort of MNLC aided data transmission not only introduces less loss in its transmitted data but also overcomes various health hazards of conventional radio frequency (RF) communication. This technique also proves that any data bit stream can be transmitted and retrieved using the proposed high gain DC-DC converter. The simulation model of the proposed system is implemented in MATLAB for various switching frequencies with its prototype of the converter developed and the results are verified.
Oscillatory and Asymptotic Behavior of Solutions of Second Order Neutral Delay Difference Equations with “Maxima”  [PDF]
Ramalingam Arul, Manvel Angayarkanni
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.52009
Abstract:

In this paper, we study the oscillatory and asymptotic behavior of second order neutral delay difference equation with “maxima” of the form?\"\"

Examples are given to illustrate the main result.

Recognizing Expression Variant and Occluded Face Images Based on Nested HMM and Fuzzy Rule Based Approach  [PDF]
Parvathi Ramalingam, Shanthi Dhanushkodi
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.76083
Abstract: The face recognition with expression and occlusion variation becomes the greatest challenge in biometric applications to recognize people. The proposed work concentrates on recognizing occlusion and seven kinds of expression variations such as neutral, surprise, happy, sad, fear, disgust and angry. During enrollment process, principle component analysis (PCA) detects facial regions on the input image. The detected facial region is converted into fuzzy domain data to make decision during recognition process. The Haar wavelet transform extracts features from the detected facial regions. The Nested Hidden markov model is employed to train these features and each feature of face image is considered as states in a Markov chain to perform learning among the features. The maximum likelihood for the input image was estimated by using Baum Welch algorithm and these features were kept on database. During recognition process, the expression and occlusion varied face image is taken as the test image and maximum likelihood for test image is found by following same procedure done in enrollment process. The matching score between maximum likelihood of input image and test image is computed and it is utilized by fuzzy rule based method to decide whether the test image belongs to authorized or unauthorized. The proposed work was tested among several expression varied and occluded face images of JAFFE and AR datasets respectively.
Design and Development of Hybrid Multilevel Inverter employing Dual Reference Modulation Technique for Fuel Cell Applications
R. Seyezhai,Banuparvathy Kalpana
International Journal of Power Electronics and Drive Systems , 2011, DOI: 10.11591/ijpeds.v1i2.99
Abstract: MultiLevel Inverter (MLI) has been recognized as an attractive topology for high voltage DC-AC conversion. This paper focuses on a new dual reference modulation technique for a hybrid multilevel inverter employing Silicon carbide (SiC) switches for fuel cell applications. The proposed modulation technique employs two reference waveforms and a single inverted sine wave as the carrier waveform. This technique is compared with the conventional dual carrier waveform in terms of output voltage spectral quality and switching losses. An experimental five-level hybrid inverter test rig has been built using SiC switches to implement the proposed algorithm. Gating signals are generated using PIC microcontroller. The performance of the inverter has been analyzed and compared with the result obtained from theory and simulation. Simulation study of Proportional Integral (PI) controller for the inverter employing the proposed modulation strategy has been done in MATLAB/SIMULINK. Keywords: Multilevel inverter, SiC , dual reference modulation, switching losses, PI
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