Faculty Publications
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Item Design and implementation of a symmetrical multilevel inverter topology(Institute of Electrical and Electronics Engineers Inc., 2017) Shiva Naik, B.S.; Venkataramanaiah, J.; Reddy, K.S.; Yellasiri, Y.In this project level shifted bipolar sinusoidal Pulse Width Modulation techniques are developed over new symmetrical seven level inverter topology. The proposed SPWM techniques are Phase Disposition Technique, Phase Opposition Disposition Technique and Alternate Phase Opposition Disposition Technique which are under hard switching techniques. More number of components, complex switching patterns and charge balance problems are disadvantages of traditional cascaded MLI [1]. In this new topology, reversing voltage component is used in order to reduce the drawbacks mentioned above. So, it possesses fewer components especially in higher level inverters, reduced losses and stress over the components. Proposed techniques are validated on MATLAB-SIMULINK software. Among all the techniques, Phase Opposition disposition technique produced high RMS output voltage with low total harmonic content. © 2017 IEEE.Item Performance verification of a new cascaded transformer based multilevel inverter using modified carrier SPWM strategy(Institute of Electrical and Electronics Engineers Inc., 2018) Venkataramanaiah, J.; Yellasiri, Y.In this article, a novel cascaded transformer based multilevel inverter is presented for single phase systems. The proposed topology can produce a 19-level output waveform with fewer count parts. It consists of two bridges with individual low-frequency transformers. The bridges can generate quasi-square waveform and pulse width modulated (PWM) waveform independently and energized the two transformers whose secondary terminals are cascaded to attain the maximum number of levels in the output voltage waveform. Presence of the transformer in the configuration mainly provides the inbuilt isolation between the supply and load, higher order harmonics are filtered out due to the leakage inductance of the transformers and ratings of the power electronic switches are reduced since the transformers are boosted up the voltages. As per switching concerns, this paper presents the most common LS-SPWM technique with a new carrier to improves the fundamental magnitude and shifts the dominant harmonics into three times of the traditional strategy for the same modulation indices. The detailed loss analysis of the converter is also presented. The performance of the proposed topology is validated with MATLAB-Simulink software. © 2018 IEEE.Item A Single Stage Switched-Capacitor Hexad Boost Multilevel Inverter Featuring Boost Ability(Institute of Electrical and Electronics Engineers Inc., 2020) Shiva Naik, B.S.; Yellasiri, Y.; Venkataramanaiah, J.Nowadays, curtailment in the number of dc sources, circuit component count along with the boosting gain property of the output voltage are considered as the essential topological features for the new multilevel inverter (MLI) structures. Considering the above, a novel 13-level single-stage switched-capacitor hexad boost (S3 CHB) inverter featuring boosting gain and self-balancing ability is proposed in this paper. Each phase of the proposed \mathrm{S}^{3} CHB-MLI is designed with only 14 semiconductor switches and three electrolytic capacitors. Here, the capacitors' voltages are balanced automatically by utilizing the series-parallel technique effectively. An absence of H-bridge at the back-end makes the circuit to extend for higher levels. Capacitors' voltage ripple are analyzed in detail. Further, a cost comparison is conducted among the state-of-art MLIs to highlight the superiority of the proposed configuration. Finally, the effectiveness of the proposed \mathrm{S}^{3} CHB circuit is experimentally demonstrated. Results at different load conditions are captured to prove the inductive load capability. © 2020 IEEE.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 Conventional, wide-bandgap, and hybrid power converters: A comprehensive review(Elsevier Ltd, 2025) Suthar, A.N.; Venkataramanaiah, J.; Yellasiri, Y.This review delves into cutting-edge wide band gap (WBG) technology, a third-generation switching device, exploring its fundamental properties and system-level applications. Emphasizing silicon carbide (SiC) and gallium nitride (GaN) materials, the review highlights their superior energy efficiency in power electronic converters compared to traditional silicon (Si) materials. WBG-based converters achieve higher efficiency and reducing energy losses as compared to Si-based converters. These devices operate effectively at higher switching frequencies and reducing passive component size in direct current (DC) - alternating current (AC) applications at higher cost. Thereby, this study identifies hybrid converters combining Si and WBG switches as cost-effective solutions, achieving efficiency gains of higher percentages over fully Si-based designs. The review presents a parametric comparison among traditional, fully WBG-based, and hybrid converters, examining various aspects such as switching frequency, blocking voltages, losses, efficiency, reliability, cost, thermal constraints and device count which remain essential for the broader adoption in various applications. © 2025 Elsevier LtdItem 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 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 2019Item Experimental verification of a hybrid multilevel inverter with voltage-boosting ability(John Wiley and Sons Ltd vgorayska@wiley.com Southern Gate Chichester, West Sussex PO19 8SQ, 2020) Shiva Naik, B.; Yellasiri, Y.; Venkataramanaiah, J.A new nine-level natural-balanced boost hybrid multilevel inverter (BH-MLI) is proposed in this paper. Each phase of the proposed BH-MLI is designed with only 11 semiconductor switches and two electrolytic capacitors. Here, the capacitor voltages are balanced by utilizing the series-parallel and natural balancing techniques effectively. Furthermore, the proposed circuit eradicates the multiple DC sources by introducing a single DC link for single- and three-phase applications. The proposed topology can be easily extendible to obtain higher level output voltage waveform due to its modular-switched capacitor cells (SCCs). Besides, the higher voltage level generation does not pose high-voltage stress on any of the topology components, as the blocking voltage of all devices within the source voltage magnitude. Further, a quantitative comparison is conducted among the state-of-art switched-capacitor multilevel inverter (SC-MLIs) to highlight the superiority of the proposed configuration. Finally, the performance of the proposed BH-MLI is experimentally validated with phase disposition-pulse width modulation (PD-PWM) and round control method at different modulation indices, load conditions. © 2020 John Wiley & Sons, Ltd.