Reactive Power Control and Neutral Current Elimination of Four Wire Five Level NPC Inverter based STATCOM using 3D-SVPWM Technique

Palanisamy R.,Karthikeyan D.,Vidyasagar S.,Kalyanasundaram V.,Selvakumar K.,Vijayakumar K.,Selvabharathi D. 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

In this paper, three phase four wire fi ve level Neutral Point Clamped Inverter (NPCI) based Static synchronous Compensator (STATCOM) is implemented for reactive power control and neutral current elimination. Three dimensional Space Vector Pulse Width Modulation (3D-SVPWM) control strategy is developed to control this 5-level NPC inverter. The behaviour of static synchronous compensator is analyzed and reactive power control is done using constant DC voltage. The objective of this compensating method is to provide balanced and sinusoidal source currents under unbalanced and nonlinear load conditions and reactive power control. The 3D-SVPWM technique provides reduced harmonic content in output voltage and current, controlled source current, minimized common mode voltage and improved output voltage. In 3D-SVPWM, switching pulses are generated with non-redundant switching states, which lead to reduce the complexity in switching time calculation and computational time is less. The highlights of the paper includes the neutral current is reduced to 0.25A, source current harmonics is minimized and it provides balanced and sinusoidal source currents with help of STATCOM compensation. The simulation and experimental results demonstrates the sinusoidal and harmonics free source current and minimized neutral current for four wire fi ve level NPCI based STATCOM.

Influence of Switchgrass Generated Producer Gas Pre-adaptation on Growth and Product Distribution of Clostridium ragsdalei

Karthikeyan D. Ramachandriya,Mark R. Wilkins,Krushna N. Patil 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

Gasification-fermentation is a thermo chemicalbiologicalprocess for the production of fuels and chemicals. Producer gas cleanup is a major issue that must beaddressed for integration of these platforms. Pre-adaptationof producer gas fermenting microbes to gas impurities hasimproved tolerances to impurities and production of alcoholsin certain bacteria. In this research, the effect of switchgrassgenerated producer gas was studied with adapted andunadapted cultures of C. ragsdalei and compared tofermentations with a control of clean custom producer gas. Results indicated no inhibition to microbial growth withunadapted cells and final cell mass concentrations were22% higher when cells were exposed to switchgrass-basedproducer gas compared to control. The ethanol productivitywith adapted cells was 1.9 and 2.8 times higher thanunadapted and control treatments, respectively. Similarly,the ethanol yield (YETOH/X) of C. ragsdalei adapted toproducer gas was 119% more than the control and 35%greater than the unadapted cells used in this study. Thepresence of switchgrass-based producer gas also inducedmetabolic shifts resulting in reduction of acetic acid toethanol that increased ethanol to acetate ratios from 0.7 g/gin control to 4.9 g/g with unadapted cells and 13.7 g/g withadapted cells. Isopropanol was also observed as a productwhen switchgrass generated producer gas was used. Weconclude that cultural adaptation of C. ragsdalei to biomassgenerated producer gas during preculture stages could beused as an important strategy to enhance ethanol yields forintegrating gasification and fermentation platforms usingC. ragsdalei.

Development of a Switched Diode Asymmetric Multilevel Inverter Topology

D. Karthikeyan,Vijayakumar Krishnasamy,Mohd. Ali Jagabar Sathik 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This paper presents a new asymmetrical multilevel inverter with a reduced number of power electronic components. The proposed multilevel inverter is analyzed using two different configurations: i) First Configuration (with a switched diode) and ii) Second Configuration (without a switched diode). The presented topologies are compared with recent multilevel inverter topologies in terms of number of switches, gate driver circuits and blocking voltages. The proposed topologies can be cascaded to generate the maximum number of output voltage levels and they are suitable for high voltage applications. Various power quality issues are addressed for both of the configurations. The proposed 11-level inverter configuration is simulated using MATLAB and it is validated with a laboratory based experimental setup.

Development of a Switched Diode Asymmetric Multilevel Inverter Topology

Karthikeyan, D.,Krishnasamy, Vijayakumar,Sathik, Mohd. Ali Jagabar The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This paper presents a new asymmetrical multilevel inverter with a reduced number of power electronic components. The proposed multilevel inverter is analyzed using two different configurations: i) First Configuration (with a switched diode) and ii) Second Configuration (without a switched diode). The presented topologies are compared with recent multilevel inverter topologies in terms of number of switches, gate driver circuits and blocking voltages. The proposed topologies can be cascaded to generate the maximum number of output voltage levels and they are suitable for high voltage applications. Various power quality issues are addressed for both of the configurations. The proposed 11-level inverter configuration is simulated using MATLAB and it is validated with a laboratory based experimental setup.

ANALYSIS OF SOLUTIONS FOR THE BOUNDARY VALUE PROBLEMS OF NONLINEAR FRACTIONAL INTEGRODIFFERENTIAL EQUATIONS INVOLVING GRONWALL'S INEQUALITY IN BANACH SPACES

KARTHIKEYAN, K.,RAJA, D. SENTHIL,SUNDARARAJAN, P. The Korean Society for Computational and Applied M 2022 Journal of applied mathematics & informatics Vol.40 No.1-2

We study the existence and uniqueness of solutions for a class of boundary value problems of nonlinear fractional order differential equations involving the Caputo fractional derivative by employing the Banach's contraction principle and the Schauder's fixed point theorem. In addition, an example is given to demonstrate the application of our main results.

Reconfiguration of Photovoltaic Arrays under Partial Shading Conditions Using LSG Method for Maximum Power Extraction

Karthikeyan M.,Manimegalai D. 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

The foremost goal of this paper is to analyse output power, power Mismatch Loss (ML), Fill-Factor (FF), and efficiency metrics for different configurations. The aim of this research work is to investigate and quantify the performance of various configurations under different shading patterns. Partial shading is a significant impediment to photovoltaic (PV) array performance. This problem has the solution of reconfiguring the panels in the case of partial shadowing to give better outcomes. MATLAB/SIMULINK model was used to discuss, analyse, and compare various pv arrangements such as Series-Parallel (SP), Total-Cross-Tied (TCT), SuDoKu, and Logic-based Square Grid (LSG). The implementation and evaluation of all configurations are described using a simulation approach. The LSG method has the maximum power output of 9624 W, the highest efficiency of 11.6%, the Fill Factor of 0.61, and the lowest Mismatch Loss of 6056 W in Long-Wide (LW) shading pattern compare to all the configurations. Also, maximum power enhancement by LSG method is verified by experimentally using 7 × 7 PV array. The results shows that maximum power is enhanced by LSG method are 5.29, 8.44, 6.34, 4.26 and 8.24% when compared with TCT configuration under SN, SW, LN, LW and Diagonal shading patterns respectively.

MODEL-BASED CONTROL OF AN ELECTROPNEUMATIC BRAKE SYSTEM FOR COMMERCIAL VEHICLES

P. KARTHIKEYAN,D. B. SONAWANE,S. C. SUBRAMANIAN 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.4

A properly functioning brake system is critical for ensuring the safe operation of any vehicle on roadways. Commercial vehicles such as trucks, tractors-trailers and buses are equipped with an air brake system that uses compressed air as the energy transmitting medium. This paper presents a model-based control scheme for an electropneumatic brake system for use in commercial vehicles. A mathematical model for an electropneumatic brake system was developed and corroborated with experimental data. A control scheme was developed based on this model and was used to regulate the pressure of air inside the brake chamber according to a desired pressure trajectory. This control scheme was implemented on an experimental test bench, and its performance was studied for various values of the controller parameter. The control scheme was tested for various desired pressure trajectories reflecting actual brake operation.

Performance Analysis of Layer Pruning on Sphere Decoding in MIMO Systems

Madurakavi Karthikeyan,D. Saraswady 한국전자통신연구원 2014 ETRI Journal Vol.36 No.4

Sphere decoding (SD) for multiple-input and multipleoutputsystems is a well-recognized approach forachieving near-maximum likelihood performance withreduced complexity. SD is a tree search process, whereby alarge number of nodes can be searched in an effort to findan estimation of a transmitted symbol vector. In this paper,a simple and generalized approach called layer pruning isproposed to achieve complexity reduction in SD. Pruninga layer from a search process reduces the total number ofnodes in a sphere search. The symbols corresponding tothe pruned layer are obtained by adopting a QRM-MLDreceiver. Simulation results show that the proposedmethod reduces the number of nodes to be searched fordecoding the transmitted symbols by maintainingnegligible performance loss. The proposed techniquereduces the complexity by 35% to 42% in the low andmedium signal-to-noise ratio regime. To demonstrate thepotential of our method, we compare the results withanother well-known method — namely, probabilistic treepruning SD.

Synthesis and characterization of graphitic mesoporous carbon using metal-metal oxide by chemical vapor deposition method

Atchudan, R.,Perumal, S.,Karthikeyan, D.,Pandurangan, A.,Lee, Y.R. Elsevier 2015 Microporous and mesoporous materials Vol.215 No.-

<P>Mn/MgO was prepared by wet impregnation method and was used as a catalytic template for the growth of graphitic mesoporous carbon (GMC) using acetylene gas as carbon precursor at 900 degrees C by CVD method. The deposited carbon nanostructured material was separated from the catalytic template by the acid treatment, and was investigated by various physico-chemical techniques such as XRD, BET, SEM, TEM, and Raman spectroscopy. The BET surface area of GMC is ca. 200 m(2) g(-1). The XRD pattern and Raman spectroscopic techniques revealed the crystallinity and the degree of graphitization of mesoporous carbon. The interlayer distance of graphene sheet in GMC is around 0.34 nm. All the analytical results strongly support that the prepared mesoporous carbon to be highly ordered and well in graphitic nature. Further, the results demonstrate that the GMC synthesized by using a Mn/MgO might be a promising contender for the large-scale synthesis. (C) 2015 Elsevier Inc. All rights reserved.</P>

Anti-pyretic and anti-inflammatory activity of chloroform extract of Croton roxburghii in standard animal models

T Sivakumar,R Rajavel,D Karthikeyan,R Duraisamy,K Srinivasan,S Suresh kumar,Subhas S Karki 경희대학교 융합한의과학연구소 2008 Oriental Pharmacy and Experimental Medicine Vol.8 No.3

The chloroform extract of Croton roxburghii (Family: Euphorbiaceae) was evaluated for its antipyretic effects in Brewer’s yeast induced hyperthermia in rats. The anti-inflammatory effect of the Croton roxburghii was also evaluated by using carrageenan, dextran, histamine, serotonin induced rat paw oedema and cotton pellet induced granuloma (chronic) models in rats. The chloroform extract of Croton roxburghii (CECR) exhibited significant anti-pyretic and antiinflammatory effect at the dose 50, 100 and 200 mg/kg. Maximum inhibition (55.32%) was noted at the dose of 200 mg/kg after 3 h of drug treatment in carrageenan induced paw oedema, whereas the Indomethacin (standard drug) produced 61.33% of inhibition. The extract exhibited significant anti-inflammatory activity in dextran induced paw edema in a dose dependent manner. In the chronic model (cotton pellet induced granuloma) the CECR (200 mg/kg) and Indomethacin (10 mg/kg) showed decreased formation of granuloma tissue by 52.32% and 56.32% respectively. The extract also exhibited a significant antipyretic response in Brewer’s yeast induced pyrexia in rats. Thus, the present study revealed that the CECR exhibited significant antipyretic and anti-inflammatory activity in the tested animal models. The chloroform extract of Croton roxburghii (Family: Euphorbiaceae) was evaluated for its antipyretic effects in Brewer’s yeast induced hyperthermia in rats. The anti-inflammatory effect of the Croton roxburghii was also evaluated by using carrageenan, dextran, histamine, serotonin induced rat paw oedema and cotton pellet induced granuloma (chronic) models in rats. The chloroform extract of Croton roxburghii (CECR) exhibited significant anti-pyretic and antiinflammatory effect at the dose 50, 100 and 200 mg/kg. Maximum inhibition (55.32%) was noted at the dose of 200 mg/kg after 3 h of drug treatment in carrageenan induced paw oedema, whereas the Indomethacin (standard drug) produced 61.33% of inhibition. The extract exhibited significant anti-inflammatory activity in dextran induced paw edema in a dose dependent manner. In the chronic model (cotton pellet induced granuloma) the CECR (200 mg/kg) and Indomethacin (10 mg/kg) showed decreased formation of granuloma tissue by 52.32% and 56.32% respectively. The extract also exhibited a significant antipyretic response in Brewer’s yeast induced pyrexia in rats. Thus, the present study revealed that the CECR exhibited significant antipyretic and anti-inflammatory activity in the tested animal models.