Faculty Publications
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Item Design and Development of Multi-Phase Rectifier with Reduced Magnetic Rating(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Singh, B.This paper proposes a 20-pulse asymmetric multiphase rectifier (AMPR) suitable for medium and high-power applications. Unlike the other state-of-the-art 20-pulse delta connected autotransformers, the proposed delta connected AMPR has an ability to reduce input harmonics, maintains high efficiency and requires a magnetic rating of only 30.12% of the nominal load thereby a significant reduction in space, weight, and overall cost required are the salient features of the proposed AMPR. Firstly, the proposed AMPR configuration is simulated in MATLAB/Simulink environment for evaluating its viability under different loading conditions, and the results are illustrated. Also, a prototype is developed, and the experimental measurements obtained are presented to validate the feasibility and operability of the proposed AMPR. The proposed AMPR offers a total harmonic distortion of 3.7% and can operate at near-unity power factor complying with the IEEE and IEC standards. © 2018 IEEE.Item A 20-Pulse Asymmetric Multiphase Staggering Autoconfigured Transformer for Power Quality Improvement(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.This letter presents a 20-pulse multiphase staggering autoconfigured transformer (MSAT) for power quality improvement in medium and high power applications. The proposed autoconfigured transformer is a combination of delta and zig-zag transformers. Contrary to the prior art multipulse autoconnected transformers, magnetic rating of the proposed configuration is only 40% of the load rating in addition to improved power quality indices. Moreover, the creation of a neutral point ascribed to inbuilt zig-zag windings supplements as one of the remarkable advantages of the proposed MSAT. Therefore, with this suggested configuration, the performance of zig-zag transformer is accomplished within the autoconfigured transformer. A detailed comparison of the proposed MSAT configuration with that of other multipulse autoconnected transformers in terms of magnetic rating and power quality indices are presented. Further, the feasibility and operability of the proposed MSAT are verified and validated through experimental tests on the laboratory prototype. The test results so obtained complies with the IEEE-519 and IEC 61000-3-2 standards on power quality requirements. © 2017 IEEE.Item A New Generalized Multilevel Converter Topology Based on Cascaded Connection of Basic Units(Institute of Electrical and Electronics Engineers Inc., 2019) Jagabar Sathik, J.; Shalchi Alishah, R.; Sandeep, N.; Hosseini, S.H.; Babaei, E.; Krishnasamy, K.; Yaragatti, U.R.In this paper, a new single-phase multilevel converter (MLC) topology based on the cascade connection of novel basic units is presented. The proposed basic unit generates 17-level output voltage waveform and can be extended for higher voltage levels by using a simple cascade connection. Both the proposed basic unit and cascaded topologies are compared with other state-of-the-art MLC topologies. From the comparison results, it will be shown that the proposed topology has several advantages such as the reduced number of power electronic components, lesser number of dc sources, and blocking voltage. Moreover, the proposed MLC has reduced power losses and improved efficiency. The operability and feasibility of the proposed converter are validated through extensive simulation and experiments. Finally, the corresponding results affirming the predominance of the proposed topologies are presented. © 2013 IEEE.Item Activated carbon- supported Vanado-nickelate (IV) based hybrid materials for energy application(Elsevier Ltd, 2021) Maity, S.; BM, N.; Kella, T.; Shee, D.; Das, P.P.; Mal, S.S.The rapid development of supercapacitor (SC) technology leads to increased demand for nanofabrication of novel and effective electroactive hybrid materials for next-generation energy storage devices. Herein, nickel tetradecavanadate, K2H5[NiV14O40](NiV14), is doped into porous activated carbon (AC), for the first time, in different wt.% in order to investigate the homogeneous loading of the inorganic metal-oxide component on the AC matrix. The resulting complex, AC-NiV14, is found to have possessed an enhanced electrochemical characteristic (for both symmetric and asymmetric SC cell), which operates at a significantly higher potential of 1.2 V. The combination of the double-layer capacitance (EDLC) and the redox-active polyoxometalate cluster leads to an intrinsic increase in specific capacitance (capacity) (from 45.3 Fg?1 (54.4 Cg?1) for AC to 316 Fg?1 (379.2 Cg?1) for 15 wt.% AC-NiV14 at a current density of 1 Ag?1). It was also observed that there is an increase of 20% in the operating voltage compared to conventional AC supercapacitors with acidic aqueous electrolytes. Firstly, symmetric supercapacitor's electrochemical performances of various wt.% of NiV14 composition were studied in acidic aqueous electrolyte (0.5 M H2SO4) solution. We observed that the 15 wt.% of AC-NiV14 hybrid electrode showed remarkable specific energy value (~63.2 Wh kg?1) compared with pristine AC and NiV14 electrodes, separately. Besides, the asymmetric layout (AC//AC-NiV14) increased the potential window up to 1.5 V and enhanced the specific energy and power values (90.1 Whkg?1 and 2400 Wkg?1, respectively), with 98% coulombic efficiency. Meanwhile, the AC-NiV14//NiV14 asymmetric cell possesses a specific capacitance (capacity) of 375 Fg?1 (450 Cg?1) with a maximum power of 3140 Wkg?1 at the high current density of 2 Ag?1. © 2021 Elsevier LtdItem Asymmetric polyoxometalate-polypyrrole composite electrode material for electrochemical energy storage supercapacitors(Elsevier B.V., 2022) Anandan Vannathan, A.; Chandewar, P.R.; Shee, D.; Mal, S.Nowadays, metal-oxides impregnated conducting polymers as electrode materials are attracted much attention due to their higher stability. Here, the metal-oxide cluster, polyoxometalate (K5H2[PV4W8O40]·11H2O, PV4W8), was introduced into the polypyrrole (PPy) matrix to overcome the polymers stability issues, and thus, the resulting novel PV4W8/PPy (symmetric) composite electrode has been reported. XPS confirmed the presence of all atoms on the polymer backbone with respective oxidation states. Nevertheless, doping of PV4W8 on the conductive PPy matrix's surface can affectively improve the ion's transfer. Finally, the asymmetric PV4W8-PPy/PPy composite exhibits a prodigious specific capacitance of 291 F g−1, larger than the PPy (90.01 F g−1) and PV4W8 (39.03 F g−1) at 0.4 A g−1 current density. The PV4W8-PPy/PPy (asymmetric) electrode showed excellent cycle stability. However, a symmetric supercapacitor device based on PV4W8/PPy composite possesses a specific capacitance of 195.27 F g−1 and an energy density of 8.94 Wh kg−1 at the same current density as PV4W8-PPy/PPy (asymmetric) electrode with remarkable cycle stability. © 2021 Elsevier B.V.Item Nexus between climate policy uncertainty and economic policy uncertainty among BRIC nations: evidence from ARDL and NARDL approach(Emerald Publishing, 2025) Akshaya, A.; Gopalakrishna, B.V.Purpose – Climate policy is a collective name for the set of initiatives and legal frameworks that nations and international organizations have put in place to address the challenges of climate change. In this empirical analysis, we have studied the symmetric and asymmetric association between climate policy uncertainty (CPU) and economic policy uncertainty (EPU) among the BRIC nations. Design/methodology/approach – In the present analysis, the authors have used the autoregressive distributed lag (ARDL) and nonlinear autoregressive distributed lag (NARDL) models, which help explain the linear and nonlinear relationships among the variables. Descriptive statistics, stationarity tests and BDM statistics for nonlinearity are applied in the study to determine the data characteristics. Findings – Our model results demonstrate that the CPU has a significant impact on the EPU of the BRIC nations, except for India and the association is symmetric. India’s economic policies are more stable than those of other BRIC countries. Research limitations/implications – Due to the growing issue of climate change and its impact on economic policies, emerging nations must develop stable climate action plans to mitigate the effects on their economic policies. This empirical investigation will help economic policymakers and businesses to adopt appropriate growth and development policies. Originality/value – This study makes a novel contribution by being the first to examine how CPU influences EPU in emerging economies. The research question and methodological approach not only enrich the academic discourse but also provide valuable insights for the formulation of economic policy. © 2025 Emerald Publishing Limited