Natural Balancing of the Neutral Point Potential of a Three-Level Inverter with Improved Firefly Algorithm

M. Gnanasundari,M. Rajaram,Sujatha Balaraman 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

Modern power systems driven by high-power converters have become inevitable in view of the ever increasing demand for electric power. The total power loss can be reduced by limiting the switching losses in such power converters; increased power efficiency can thus be achieved. A reduced switching frequency that is less than a few hundreds of hertz is applied to power converters that produce output waveforms with high distortion. Selective harmonic elimination pulse width modulation (SHEPWM) is an optimized low switching frequency pulse width modulation method that is based on offline estimation. This method can pre-program the harmonic profile of the output waveform over a range of modulation indices to eliminate low-order harmonics. In this paper, a SHEPWM scheme for three-phase three-leg neutral point clamped inverter is proposed. Aside from eliminating the selected harmonics, the DC capacitor voltages at the DC bus are also balanced because of the symmetrical pulse pattern over a quarter cycle of the period. The technique utilized in the estimation of switching angles involves the firefly algorithm (FA). Compared with other techniques, FA is more robust and entails less computation time. Simulation in the MATLAB/SIMULINK environment and experimental verification in the very large scale integration platform with Spartan 6A DSP are performed to prove the validity of the proposed technique.

Natural Balancing of the Neutral Point Potential of a Three-Level Inverter with Improved Firefly Algorithm

Gnanasundari, M.,Rajaram, M.,Balaraman, Sujatha The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

Modern power systems driven by high-power converters have become inevitable in view of the ever increasing demand for electric power. The total power loss can be reduced by limiting the switching losses in such power converters; increased power efficiency can thus be achieved. A reduced switching frequency that is less than a few hundreds of hertz is applied to power converters that produce output waveforms with high distortion. Selective harmonic elimination pulse width modulation (SHEPWM) is an optimized low switching frequency pulse width modulation method that is based on offline estimation. This method can pre-program the harmonic profile of the output waveform over a range of modulation indices to eliminate low-order harmonics. In this paper, a SHEPWM scheme for three-phase three-leg neutral point clamped inverter is proposed. Aside from eliminating the selected harmonics, the DC capacitor voltages at the DC bus are also balanced because of the symmetrical pulse pattern over a quarter cycle of the period. The technique utilized in the estimation of switching angles involves the firefly algorithm (FA). Compared with other techniques, FA is more robust and entails less computation time. Simulation in the MATLAB/SIMULINK environment and experimental verification in the very large scale integration platform with Spartan 6A DSP are performed to prove the validity of the proposed technique.

A binder-free wet chemical synthesis approach to decorate nanoflowers of bismuth oxide on Ni-foam for fabricating laboratory scale potential pencil-type asymmetric supercapacitor device

Shinde, N. M.,Xia, Qi Xun,Yun, Je Moon,Singh, Saurabh,Mane, Rajaram S.,Kim, Kwang-Ho Royal Society of Chemistry 2017 Dalton Transactions Vol. No.

<▼1><P>The synthesis and asymmetric supercapacitor application of a bismuth oxide (Bi2O3) electrode consisting of arranged nano-platelets for evolving a flower-type surface appearance on nickel-foam (Bi2O3–Ni–F) are described.</P></▼1><▼2><P>The present study involves the synthesis of a bismuth oxide (Bi2O3) electrode consisting of an arranged nano-platelets for evolving a flower-type surface appearance on nickel-foam (Bi2O3–Ni–F) by a simple, inexpensive, binder-free and one-step chemical bath deposition (CBD) method, popularly known as a wet chemical method. The as-prepared Bi2O3 on Ni-foam, as an electrode material, demonstrates 557 F g<SUP>−1</SUP> specific capacitance (SC, at 1 mA cm<SUP>−2</SUP>), of which 85% is retained even after 2000 cycles. With specific power density of 500 kW kg<SUP>−1</SUP>, the Bi2O3–Ni–F electrode documents a specific energy density of 80 Wh kg<SUP>−1</SUP>. Furthermore, a portable asymmetric supercapacitor device, <I>i.e.</I> a pencil-type cell consisting of Bi2O3–Ni–F as an anode and graphite as a cathode in 6 M KOH aqueous electrolyte solution, confirms 11 Wh kg<SUP>−1</SUP> and 720 kW kg<SUP>−1</SUP> specific energy and specific power densities, respectively. An easy and a simple synthesis approach for manufacturing a portable laboratory scale pencil-type supercapacitor device is a major outcome of this study, which can also be applied for ternary and quaternary metal oxides for recording an enhanced performance. In addition, we presented a demonstration of lighting a light emitting diode (LED) using a home-made pencil-type supercapacitor device which, finally, has confirmed the scaling and technical potentiality of Bi2O3–Ni–F in energy storage devices.</P></▼2>

Ultra-rapid chemical synthesis of mesoporous Bi₂O₃ micro-sponge-balls for supercapattery applications

Shinde, Nanasaheb M.,Xia, Qi Xun,Yun, Je Moon,Shinde, Pritamkumar V.,Shaikh, Shoyebmohamad M.,Sahoo, Rakesh K.,Mathur, Sanjay,Mane, Rajaram S.,Kim, Kwang Ho Elsevier 2019 ELECTROCHIMICA ACTA Vol.296 No.-

<P><B>Abstract</B></P> <P>Polycrystalline and mesoporous bismuth oxide (Bi<SUB>2</SUB>O<SUB>3</SUB>) micro-sponge-balls of 4–7 μm in diameter comprising of 58–65 (±2) nm upright standing petals, separated by 100–700 (±50) nm crevices, are synthesized directly onto 3D Ni-foam at room-temperature (27 °C) using Tritonx-100 surfactant-mediated soft wet chemical method. After knowing the phase purity, surface area, pore-size distribution, micro-sponge-ball-type surface morphology, elemental analysis and binding energy confirmations of Bi<SUB>2</SUB>O<SUB>3</SUB>, a material with quasi-faradaic redox reactions responsible for supercapattery type behavior, are measured and explored. At a low scan rate, the specific capacitance of Bi<SUB>2</SUB>O<SUB>3</SUB> sponge-ball electrode, measured from 0.4 to 1.80 A g<SUP>−1</SUP> current density, decreases from 559 to 211 F g<SUP>−1</SUP> which is equivalent to a capacity from 155 to 58 mAh.g<SUP>−1</SUP>. An asymmetric supercapacitor (ASC) device assembly of Bi<SUB>2</SUB>O<SUB>3</SUB> sponge-ball electrode with graphite i.e. Bi<SUB>2</SUB>O<SUB>3</SUB>//graphite demonstrates excellent electrochemical properties with 8 Wh kg<SUP>−1</SUP> energy density at 2040 W kg<SUP>−1</SUP> power density, and about 80% cycling retention over 5000 redox cycle operations. A demonstration of LED with full-bright intensity during discharge process of the Bi<SUB>2</SUB>O<SUB>3</SUB>//graphite ASC device suggests its practical potentiality and industrial viability.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Tailoring the morphology followed by the electrochemical performance of NiMn-LDH nanosheet arrays through controlled Co-doping for high-energy and power asymmetric supercapacitors

Singh, Saurabh,Shinde, Nanasaheb M.,Xia, Qi Xun,Gopi, Chandu V. V. M.,Yun, Je Moon,Mane, Rajaram S.,Kim, Kwang Ho Royal Society of Chemistry 2017 Dalton Transactions Vol. No.

<▼1><P>A NiCoMn-LDH (10%)//rGO asymmetric supercapacitor device with 574 Wh kg<SUP>−1</SUP> energy density at 749.9 W kg<SUP>−1</SUP> power density and 89.4% retention even after 2500 cycles has been explored.</P></▼1><▼2><P>Herein, we tailor the surface morphology of nickel–manganese-layered double hydroxide (NiMn-LDH) nanostructures on 3D nickel-foam <I>via</I> a step-wise cobalt (Co)-doping hydrothermal chemical process. At the 10% optimum level of Co-doping, we noticed a thriving tuned morphological pattern of NiMn-LDH nanostructures (NiCoMn-LDH (10%)) in terms of the porosity of the nanosheet (NS) arrays which not only improves the rate capability as well as cycling stability, but also demonstrates nearly two-fold specific capacitance enhancement compared to Co-free and other NiCoMn-LDH electrodes with a half-cell configuration in 3 M KOH, suggesting that Co-doping is indispensable for improving the electrochemical performance of NiMn-LDH electrodes. Moreover, when this high performing NiCoMn-LDH (10%) electrode is employed as a cathode material to fabricate an asymmetric supercapacitor (ASC) device with reduced graphene oxide (rGO) as an anode material, excellent energy storage performance (57.4 Wh kg<SUP>−1</SUP> at 749.9 W kg<SUP>−1</SUP>) and cycling stability (89.4% capacitive retention even after 2500 cycles) are corroborated. Additionally, we present a demonstration of illuminating a light emitting diode for 600 s with the NiCoMn-LDH (10%)//rGO ASC device, evidencing the potential of the NiCoMn-LDH (10%) electrode in fabricating energy storage devices.</P></▼2>

Structurally Enhanced Correlation Tracking

( Mayur Rajaram Parate ),( Kishor M. Bhurchandi ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.10

In visual object tracking, Correlation Filter-based Tracking (CFT) systems have arouse recently to be the most accurate and efficient methods. The CFT's circularly shifts the larger search window to find most likely position of the target. The need of larger search window to cover both background and object make an algorithm sensitive to the background and the target occlusions. Further, the use of fixed-sized windows for training makes them incapable to handle scale variations during tracking. To address these problems, we propose two layer target representation in which both global and local appearances of the target is considered. Multiple local patches in the local layer provide robustness to the background changes and the target occlusion. The target representation is enhanced by employing additional reversed RGB channels to prevent the loss of black objects in background during tracking. The final target position is obtained by the adaptive weighted average of confidence maps from global and local layers. Furthermore, the target scale variation in tracking is handled by the statistical model, which is governed by adaptive constraints to ensure reliability and accuracy in scale estimation. The proposed structural enhancement is tested on VTBv1.0 benchmark for its accuracy and robustness.

An Exploratory Study of Cloud Service Level Agreements - State of the Art Review

( Saravanan K ),( Rajaram M ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.3

Cloud computing evolve as a cost effective business model for IT companies to focus on their core business without perturbing on infrastructure related issues. Hence, major IT firms and Small & Medium Enterprises (SME) are adopting cloud services on rental basis from cloud providers. Cloud Service level agreements (SLA) act as a key liaison between consumers and providers on renting Anything as a Service (AaaS). Design of such an agreement must aim for greater profit to providers as well as assured availability of services to consumers. However in reality, cloud SLA is not satisfying the parties involved because of its inherent complex nature and issues. Also currently most of the agreements are unilateral to favour the provider. This study focuses on comprehensive, 360-degree survey on different aspects of the cloud service agreements. We detailed the life cycle of SLA based on negotiation, different types of SLA, current standards, languages & characteristics, metrics and issues involved in it. This study will help the cloud actors to understand and evaluate the agreements and to make firm decision on negotiation. The need for standardized, bilateral, semantic SLA has also been proposed.

Density based Multiclass Support Vector Machine using IoT driven Service Oriented Architecture for Predicting Cervical Cancer

Sakthi A,Rajaram M 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.11

Cervical Cancer stands out among those deadliest diseases, which threatens women in an alarming rate causing approximately 2, 66,000 mortalities per annum worldwide. This cancer can be diagnosed early enough through Pap smear test; a cervical cancer screening program. Finding out the true positive rates of the Cervical Cancer cells with precision is more complex when identifying the same categories of the cancer disease. Various researchers have proposed many approaches over the past four decades and the solutions are pertinent to cervical cancer; however, the challenge remains partially unresolved. The significant contribution of this paper is in two folds, firstly discuss a cloud ready Adapter Driven Service Oriented Architecture (RESPRO 3.0), developed by us for automated screening of Pap Smear can be extended to any International Classification of Diseases (ICD). Secondly, present an Internet of Things (IoT) driven Cervical Cancer prediction adapter built for RESPRO 3.0 based on Density based Multiclass Support Vector Machines (MCSVM) in combination with Polynomial Kernel Trick. The density parameters provide unique space in identifying cervical cancer cell categories compared to exising researches. This cloud solution’s results are bench marked and verified against cyto technician’s ground truth results, found to be highly satisfactory with respect to 93% Sensitivity and 99% Specificity while minimizing test repeatability ratio for the supervised training set of images.

Real time Implementation of SHE PWM in Single Phase Matrix Converter using Linearization Method

Karuvelam, P. Subha,Rajaram, M. The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

In this paper, a real time implementation of selective harmonic elimination pulse width modulation (SHEPWM) using Real Coded Genetic Algorithm (RGA), Particle Swarm Optimization technique (PSO) and a new technique known as Linearization Method (LM) for Single Phase Matrix Converter (SPMC) is designed and discussed. In the proposed technique, the switching frequency is fixed and the optimum switching angles are obtained using simple mathematical calculations. A MATLAB simulation was carried out, and FFT analysis of the simulated output voltage waveform confirms the effectiveness of the proposed method. An experimental setup was also developed, and the switching angles and firing pulses are generated using Field Programmable Gate Array (FPGA) processor. The proposed method proves that it is much applicable in the industrial applications by virtue of its suitability in real time applications.

Real time Implementation of SHE PWM in Single Phase Matrix Converter using Linearization Method

P. Subha Karuvelam,M. Rajaram 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

In this paper, a real time implementation of selective harmonic elimination pulse width modulation (SHEPWM) using Real Coded Genetic Algorithm (RGA), Particle Swarm Optimization technique (PSO) and a new technique known as Linearization Method (LM) for Single Phase Matrix Converter (SPMC) is designed and discussed. In the proposed technique, the switching frequency is fixed and the optimum switching angles are obtained using simple mathematical calculations. A MATLAB simulation was carried out, and FFT analysis of the simulated output voltage waveform confirms the effectiveness of the proposed method. An experimental setup was also developed, and the switching angles and firing pulses are generated using Field Programmable Gate Array (FPGA) processor. The proposed method proves that it is much applicable in the industrial applications by virtue of its suitability in real time applications.