Photocatalytic degradation of synthetic dye by immobilised doped nanoparticles on polyurethane foam reactor using RSM

T. Usharani,R. Baskar,B. Palanisamy 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.5

The aim of this work is to optimize the functional factors that influence the efficiency of the photodegradation of methyleneblue using SiO2–TiO2 nanoparticles on polyurethane foam reactor by UV-TiO2 photocatalytic process. The experimentalfactors like dye concentration, pH value, temperature, reaction time are analyzed by RSM (Response Surface Methodology)to achieve the efficacy of the best textile dye decomposition. The effect of operational factors to check the photodegradationefficiency of the methylene blue (MB) for SiO2 nanoparticles and SiO2-TiO2 nanoparticles are examined by response surfacemethodology and contour plots. The degradation percentage of MB by SiO2 and SiO2-TiO2 nanoparticles are 40.32% and67.01% respectively. The best values of MB decomposition is achieved by SiO2-TiO2 with 10 ppm initial dye concentration, pH6.88, temperature of 32 oC and 480 min reaction time. The satisfactory results is obtained through the correlation of theexperimental values and predicted data by regression analysis (R2 = 0.9984).

A Hysteresis Current Controller for PV-Wind Hybrid Source Fed STATCOM System Using Cascaded Multilevel Inverters

Palanisamy, R.,Vijayakumar, K. The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

This paper elucidates a hysteresis current controller for enhancing the performance of static synchronous compensator (STATCOM) using cascaded H-bridge multilevel inverter. Due to the rising power demand and growing conventional generation costs a new alternative in renewable energy source is gaining popularity and recognition. A five level single phase cascaded multilevel inverter with two separated dc sources, which is energized by photovoltaic - wind hybrid energy source. The voltages across the each dc source is balanced and standardized by the proposed hysteresis current controller. The performance of STATCOM is analyzed by connecting with grid connected system, under the steady state & dynamic state. To reduce the Total Harmonic Distortion (THD) and to improve the output voltage, closed loop hysteresis current control is achieved using PLL and PI controller. The performance of the proposed system is scrutinized through various simulation results using matlab/simulink and hardware results are also verified with simulation results.

A Hysteresis Current Controller for PV-Wind Hybrid Source Fed STATCOM System Using Cascaded Multilevel Inverters

R. Palanisamy,K. Vijayakumar 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

This paper elucidates a hysteresis current controller for enhancing the performance of static synchronous compensator (STATCOM) using cascaded H-bridge multilevel inverter. Due to the rising power demand and growing conventional generation costs a new alternative in renewable energy source is gaining popularity and recognition. A five level single phase cascaded multilevel inverter with two separated dc sources, which is energized by photovoltaic - wind hybrid energy source. The voltages across the each dc source is balanced and standardized by the proposed hysteresis current controller. The performance of STATCOM is analyzed by connecting with grid connected system, under the steady state & dynamic state. To reduce the Total Harmonic Distortion (THD) and to improve the output voltage, closed loop hysteresis current control is achieved using PLL and PI controller. The performance of the proposed system is scrutinized through various simulation results using matlab/simulink and hardware results are also verified with simulation results.

A SVPWM Control Strategy for Capacitor Voltage Balancing of Flying Capacitor Based 4-Level NPC Inverter

R. Palanisamy,V. Shanmugasundaram,S. Vidyasagar,V. Kalyanasundaram,K. Vijayakumar 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

A Space Vector Pulse Width Modulation (SVPWM) control strategy is implemented for capacitor voltage balancing of Flying Capacitor (FC) based 4-level Neutral Point Clamped (NPC) inverter. This fl ying capacitor based 4-level NPC inverter is developed for medium voltage and high power applications. This system includes 6 power switching devices, 2 clamping diodes and 2 fl ying capacitors per leg. The fl ying capacitors ensure to operate inverter normally and all the switching devices share the voltage stresses in identical manner. Also it controls the voltage across each capacitor and maintained at V dc /3 times of applied dc voltage. The proposed SVPWM method takes advantage of utilizing redundancy switching states to control and balance the voltage across the capacitor using nearest switching state vector selection method. Moreover, this system provides reduced total harmonic distortion (THD), and minimized voltage stress. The control technique is implemented without using any look-up tables or eff ective logic tables or trigonometric functions. The simulation and experimental results of this proposed verifi ed are verifi ed using Matlab-simulink and FPGA controller respectively.

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.

Facile, Morphology-Controlled and Mass Production of 0D-Ag/2D-g-C3N4/3D-TiO2 Nano-Composite Materials: Effect of Silver Morphology and Loading on the Electrochemical Performance

R. Ranjithkumar,P. Lakshmanan,N. Palanisami,P. Devendran,N. Nallamuthu,S. Sudhahar,M. Krishna Kumar 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.2

The 0D-Ag/2D-g-C3N4/3D-TiO2 nano-composite materials were fabricated by simple and mass production method. It involvesthe combination of incipient wetness impregnation and thermal spreading techniques. By changing the order of impregnationand thermal spreading, silver nanoparticles with “on-top” and “embedded” morphologies could be selectively controlled. Thethermal spreading followed by impregnation (TS-IM) leads to the “on-top” structure [Ag/g-C3N4/TiO2] while, the reverseorder (IM-TS) produces the embedded silver nanoparticles [g-C3N4/Ag/TiO2]. The 16%Ag/g-C3N4/TiO2 (TS-IM) sampleexhibited the best performance due to the presence of very small and highly dispersed silver nanoparticles over g-C3N4/TiO2 sample. The loading of silver not only doubled the specific capacitance but also stabilized the recycling performanceagainst deactivation. This study reveals easy and performance tunable synthesis of Ag/g-C3N4/TiO2 nano-composite materialstowards energy-storage applications.

CFD analysis of heat transfer and pressure drop in helically coiled heat exchangers using Al2O3 / water nanofluid

P. C. Mukesh Kumar,K. Palanisamy,J. Kumar,R. Tamilarasan,S. Sendhilnathan 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2

In this investigation, the heat transfer coefficient and pressure drop of a helically coiled tube heat exchanger handling Al2O3/ waternanofluids is made by using computational fluid dynamics fluent (CFD) software package. This was done under laminar flow conditionin the Dean number (De) range of 1650-2650 and the nanoparticles volume concentration of 0.1%, 0.4% and 0.8%. The effect of someimportant parameters such as nanoparticle volume concentration and Dean number (De) on heat transfer and pressure drop is studied. The coiled tube side Nusselt number (Nu) is found to be 30% higher than water at maximum De. The maximum pressure drop is found to be9% higher than water. It is also found that the Nu and pressure drop significantly increase with increasing particle volume concentrationand De. It is also found that the experimental friction factor increases with increasing the particle volume concentration and De. The CFDNu and pressure drop results have been compared with the experimental and theoretical results. On comparison, it is found that the CFDsimulation results show good agreement with the experimental and theoretical results. It is concluded that the CFD approach gives goodprediction for heat transfer coefficient and pressure drop in a shell and helically coiled tube heat exchanger using Al2O3/ water nanofluids. The average relative error between experimental Nu, pressure drop results and CFD results are found to be 8.5% and 9.5% respectively.