Faculty Publications
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Publications by NITK Faculty
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Item A new single-phase multilevel inverter with improved modulation technique(John Wiley and Sons Ltd, 2023) Nageswar Rao, B.; Yellasiri, Y.; Shiva Naik, B.; Aditya, K.; K Panda, A.This article proposes a seventeen-level (17L) inverter with a common leg configuration and an improved modulation technique. The proposed inverter uses only 10 switches, one toroidal core transformer, and one dc source. Therefore, the proposed design offers less control complexity with reduced cost and volume. Additionally, the suggested modulation technique improves the load voltage quality by minimizing the harmonic content. Simulation and laboratory studies are performed to confirm the proficiency of the suggested inverter with a new modulation technique. Further, a thorough comparison with recent transformer-based circuits is carried out to highlight the benefits of the proposed structure. © 2023 John Wiley & Sons Ltd.Item A modified T-type multilevel inverter for renewable energy applications(Elsevier Ltd, 2024) Nageswar Rao, B.; Yellasiri, Y.; Shiva Naik, B.S.; Aditya, K.; Panda, A.K.The primary challenge in integrating renewable resources into grids using multilevel inverters (MLI) is the need for many separate DC sources and switching device counts. Transformer-based multilevel inverters (TMIs) have emerged to address this issue, aiming to minimize system components and boost source voltage with a single DC source. This research article introduces a novel TMI topology that utilizes only a single DC source and incorporates ten switches to produce good-quality load voltage with high magnitude. The proposed TMI offers several structural advantages, including self-galvanic isolation, reduced switching devices and uniform voltage levels across all turn ratios. Additionally, the TMI operates a switching method called pulse width modulation, which provides the gating pulses to all the power semiconductor devices in the proposed TMI. An experimental model has been created in a laboratory environment, and simulations are performed using the MATLAB/Simulink platform to assess the effectiveness of the suggested TMI. Furthermore, a comparison between the suggested TMI circuit and other recent TMI designs with similar characteristics is performed. This comparison is carried out to assess and validate the superior features of the proposed TMI over the alternative designs. © 2024 Elsevier B.V.Item A new method for selecting optimum levels in asymmetric Cascaded H-Bridge-Multilevel Inveter with variable DC sources(John Wiley and Sons Ltd, 2025) Venkataramanaiah, J.; Yadav, G.; Balaji, J.; Yellasiri, Y.In general, cascaded H-bridge multilevel inverters (CHB-MLI) are typically operated with either symmetrical or asymmetrical input DC sources, set at predefined specific ratios such as binary (1:2) or trinary (1:3) in the case of asymmetry, to achieve the desired output voltage waveform. However, if any DC source fails to provide the predefined voltage magnitude, or CHB-MLIs with unspecified DC source ratios are utilized, the output voltage waveform may exhibit unequal magnitudes between consecutive levels, thereby causing a significant increase in total harmonic distortion (THD). Conventionally, to mitigate this effect, the corresponding H-bridge is bypassed through zero voltage switching, which leads to an additional burden on the remaining H-bridges to serve the same load. To reduce the burden on the remaining cells and improve the THD profile of the inverter, this article proposes a novel method for CHB-MLI with varying DC magnitudes. It aims to enhance the quality of the output voltage waveform by strategically selecting optimum voltage levels rather than utilizing all available levels when CHB-MLI has unspecified or variable DC sources. This approach can achieve a more balanced distribution of voltage magnitudes across successive levels by eliminating redundant states. Moreover, the proposed technique can reduce switch losses and enhance the converter's efficiency. The proposed method is validated through MATLAB/Simulink software simulations, followed by experimental verification. © 2024 John Wiley & Sons Ltd.