Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
16 results
Search Results
Item A review on symmetric, asymmetric, hybrid and single DC sources based multilevel inverter topologies(Elsevier Ltd, 2017) Venkataramanaiah, J.; Yellasiri, Y.; Panda, A.K.In recent past, multilevel inverters(MLIs) are treated as sophisticated power conversion systems demanded for high power medium voltage applications. The aim of this article is to review on recent examined multilevel inverter topologies which can be classified into four groups according to the DC voltage supplied to each fundamental unit and/or arrangement of non-identical fundamental units in an one configuration: Symmetric, Asymmetric, Hybrid and Single DC source topologies. In each group, several new versions have been constructed for last few decades. In this study the position (design and functionality) of each and every topology and also every group are reviewed. Further, a special attention is focused on Single DC source MLIs. Finally at the end of the review, merits, limitations and adequate applications are clearly mentioned. Thus, present review provides complete overview among newly developed multilevel inverters. © 2017 Elsevier LtdItem Thermo-catalytic degradation of low density polyethylene to liquid fuel over kaolin catalyst(Inderscience Publishers, 2014) Panda, A.K.; Singh, R.K.Waste low-density polyethylene samples were subjected to thermo-catalytic degradation using kaolin as catalyst in a batch reactor at temperature range of 400 to 500°C and atmospheric pressure. The quality and yield of the condensable product has been studied as a function of temperature and amount of catalyst. Both in thermal and catalytic degradation, the condensable fraction was less viscous liquid oil at low temperatures (up to 450°C), whereas with increase of temperature (from 475°C) the fraction became viscous and waxy. The recovery of condensable fraction increased from 30.8 wt.% at 400°C to 71.45% at 450°C and further increased to a maximum of 86.65wt.% at 500°C in absence of catalyst. The catalyst increased the yield of the condensable product and decreased the reaction time. The highest yield of liquid fraction at 450°C was 79.5 wt.% with 1:2 catalyst to plastics ratio. The composition of the oil obtained at optimum reaction condition was characterised by gas chromatography-mass spectroscopy (and found consisting of paraffins and olefins with mainly C10-C16 components. Fuel properties of the oil obtained by different standard methods are similar to petrochemical fuels. © 2014 Inderscience Enterprises Ltd.Item Conversion of waste polypropylene to liquid fuel using acid-activated kaolin(SAGE Publications Ltd, 2014) Panda, A.K.; Singh, R.K.Waste polypropylene was subjected to thermal degradation in the presence of kaolin and acid-treated kaolin, with different catalyst-to-plastics ratios, in a semi-batch reactor at a temperature range of 400-550°C to obtain optimized process conditions for the production of liquid fuels. The effects of process temperature, catalyst and feed composition on yield and quality of the oil were determined. For a thermal decomposition reaction at up to 450°C, the major product is volatile oil; and the major products at a higher temperature (475-550°C) are either viscous liquid or wax. The highest yield of condensed fraction in the thermal reaction is 82.85% by weight at 500°C. Use of kaolin and acid-treated kaolin as a catalyst decreased the reaction time and increased the yield of liquid fraction. The major product of catalysed degradation at all temperatures is highly volatile liquid oil. The maximum oil yield using kaolin and acidtreated kaolin is 87.5% and 92%, respectively, at 500°C. The oil obtained was characterized using GC-MS for its composition and different fuel properties by IS methods. © The Author(s) 2014.Item Investigation on stacked cascade multilevel inverter by employing single-phase transformers(Elsevier B.V., 2016) Yellasiri, Y.; Panda, A.K.In the present paper a new version of multilevel inverter is investigated. This new version is based on hybrid association of commutation cells with H-bridge cells. The association allows a significant reduction of the volume of the capacitors. In fact, presented topology allows us to work on higher input voltage levels with the same power switches. This new version is generally called as SCMI (stacked cascade multilevel inverter). The proposed inverter has potential to generate high quality waveforms, reduction in switching frequency, capable to operate at higher voltage levels and finally utilizes minimum number of switching components. The presented version of SCMI is simulated in Matlab-simulink and further, experimental validation is carried out in the laboratory with prototype setup. © 2016 Karabuk UniversityItem Investigation on cascade multilevel inverter with symmetric, asymmetric, hybrid and multi-cell configurations(Ain Shams University editor@eng.asu.edu.eg, 2017) Yellasiri, Y.; Venkataramanaiah, J.; Panda, A.K.; Dhanamjayulu, C.; Pakala, P.In recent past, numerous multilevel architectures came into existence. In this background, cascaded multilevel inverter (CMLI) is the promising structure. This type of multilevel inverters synthesizes a medium voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic allows one to achieve high-quality output voltage and current waveforms. However, when the number of levels increases switching components and the count of dc sources are also increased. This issue became a key motivation for the present paper. The present paper is devoted to investigate different types of CMLI which use less number of switching components and dc sources and finally proposed a new version of Multi-cell based CMLI. In order to verify the proposed topology, MATLAB – simulations and hardware verifications are carried out and results are presented. © 2016 Ain Shams UniversityItem Development of a New Hybrid Multilevel Inverter Using Modified Carrier SPWM Switching Strategy(Institute of Electrical and Electronics Engineers Inc., 2018) Venkataramanaiah, J.; Yellasiri, Y.; Panda, A.K.This letter presents a single-phase cascaded transformer based multilevel inverter with a modified carrier-based level shift sinusoidal pulse width modulation (LS-SPWM) technique. The developed topology has two bridges with individual low frequency transformers. The bridges can generate quasi-square waveform and pulse width modulated waveform independently and energized the two transformers whose secondary terminals are cascaded to attain 19-level output voltage waveform across the load. The anticipated configuration has the least number of components to reduce the cost and enhance the reliability of the converter for medium power applications with inbuilt isolation. Furthermore, this letter presents the most common LS-SPWM technique with a new carrier to enhance the fundamental magnitude and shifts the dominant harmonics into three times of the traditional strategy for the same modulation indices. The performance of the proposed topology is validated with experimental results. © 1986-2012 IEEE.Item Design and development of a novel 19-level inverter using an effective fundamental switching strategy(Institute of Electrical and Electronics Engineers Inc., 2018) Venkataramanaiah, J.; Yellasiri, Y.; Panda, A.K.This paper presents a single-phase 19-level inverter with fewer switching components, leading to reducing the cost and enhancing reliability for renewable applications. The anticipated multilevel inverter has two bridges that generate quasi-square and seven-level uneven waveforms with equal magnitude steps. Two voltage waveforms are cascaded at secondary side of transformers to create the 19-level output voltage waveform. Furthermore, to find the appropriate switching instants of the proposed configuration, a new fundamental switching method called the fundamental sine quantized switching technique is presented. In fact, it has the capacity to provide the N number of switching instants with less computational efforts, and attain optimized total harmonic distortion in the output voltage. Finally, performance of the proposed topology is validated with simulations and a hardware setup. © 2013 IEEE.Item Faster Biomineralization and Tailored Mechanical Properties of Marine-Resource-Derived Hydroxyapatite Scaffolds with Tunable Interconnected Porous Architecture(American Chemical Society service@acs.org, 2019) Hadagalli, K.; Panda, A.K.; Mandal, S.; Basu, B.Although hydroxyapatite (HA)-based porous scaffolds have been widely researched in the last three decades, the development of naturally derived biomimetic HA with a tunable elastic modulus and strength together with faster biomineralization properties has not yet been achieved. To address this specific issue, we report here a scalable biogenic synthesis approach to obtain submicron HA powders from cuttlefish bone. The marine-resource-derived HA together with different pore formers can be conventionally sintered to produce physiologically relevant scaffolds with porous architecture. Depending on pore formers, the scaffolds with a range of porosity of up to 51% with a larger range of pore sizes up to 50 ?m were fabricated. An empirical relationship between the compression strength and the elastic modulus with fractional porosity was established. A combination of moderate compressive strength (12-15 MPa) with an elastic modulus up to 1.6 GPa was obtained from cuttlefish-bone-derived HA with wheat flour as the pore former. Most importantly, the specific HA scaffold supports the faster nucleation and growth of the biomineralized apatite layer with full coverage within 3 days of incubation in simulated body fluid. More importantly, the marine-species-derived HA supported better adhesion and proliferation of murine osteoblast cells than HA sintered using powders from nonbiogenic resources. The spectrum of physical and biomineralization properties makes cuttlefish-bone-derived porous HA a new generation of implantable biomaterial for potential application in cancellous bone regeneration. © 2019 American Chemical Society.Item A Fuzzy Logic Based Switching Methodology for a Cascaded H-Bridge Multi-Level Inverter(Institute of Electrical and Electronics Engineers Inc., 2019) Azeem, H.; Yellasiri, Y.; Jammala, V.; Shiva Naik, B.S.; Panda, A.K.In this letter, an unusual switching technique is implemented using a fuzzy logic approach. The proposed technique simplifies the conventional method by eliminating the traditional logic-gate design. The fuzzy logic pulse generator acts as a lookup table as well as a pulse generator. On the basis of the modulation index as input, controlled membership functions (MFs) and rules of the fuzzy logic controller open various possibilities of producing pulses directly. The proposed technique is evaluated on the cascaded multi-level inverter with symmetric and asymmetric operations using selective harmonic elimination pulsewidth modulation. MFs are designed on the basis of pre-calculated firing conditions for different modulation index values. Hardware verification is carried out to support the proposed switching technique. © 1986-2012 IEEE.Item Design and implementation of a novel nine-level MT-MLI with a self-voltage-balancing switching technique(Institution of Engineering and Technology kvukmirovic@theiet.org, 2019) Shiva Naik, B.S.; Yellasiri, Y.; Venkataramanaiah, J.; Panda, A.K.In this study, a novel nine-level modified T-type multilevel inverter (MT-MLI) with a simple capacitor balancing technique is proposed. The proposed MT-MLI circuit can generate higher levels with a single DC source and the minimum number of switching components. Each phase of the proposed topology contains ten switches and one flying capacitor (FC). The DC source voltage is divided into two parts with the help of capacitors. Phase disposition-sine pulse-width modulation technique is employed to regulate the DC-link capacitors and FC voltages. To reduce the control complexity of FC-based circuits, quarter-cycle selector is introduced to control the FC voltage within the given half fundamental cycle using redundant states, so an external capacitor charging setup is not required. Furthermore, to highlight the potential merits of the proposed MT-MLI, the comparison is made among state-of-the-art MLIs. Simulation verification of the MT-MLI is done using MATLAB/ Simulink, and then hardware verifications are done using the laboratory prototype setup with Opal-RT controller. Finally, adequate results are presented to validate the proposed MT-MLI. © The Institution of Engineering and Technology 2019