Faculty Publications
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Item A novel single source multilevel inverter with hybrid switching technique(John Wiley and Sons Ltd, 2022) Nageswar Rao, B.; Yellasiri, Y.; Shiva Naik, B.; Venkataramanaiah, J.; Aditya, K.; Panda, A.A novel multilevel inverter (MLI) configuration with the hybrid switching technique is presented in this paper. The proposed MLI consists of the H-bridge combination with unidirectional switches, half-bridges, and transformers. The suggested MLI with the additional cascaded connection increases to higher voltage levels. The number of employed components in this topology is drastically minimized. Therefore, the complexity, cost, and volume of the proposed topology are also reduced. The operation of the suggested topology is tested through the improved novel switching technique. This modulation method reduces the total harmonic distortion (THD) and produces high root mean square (RMS) voltage. Further, a comprehensive comparison with the recent MLI topologies is performed to validate the merits of the suggested inverter. Simulation and experimental results verify the suggested topology performance using the new modulation technique at different loading conditions and modulation indices. © 2021 John Wiley & Sons, Ltd.Item A capacitor based single source MLI with natural balancing and less component for EV/HEV application(John Wiley and Sons Ltd, 2022) Aditya, K.; Yellasiri, Y.; Shiva Naik, B.; Nageswar Rao, B.; Panda, A.K.Due to their remarkable performance, capacitor-based inverters have recently gained attention. Hence, a new capacitor-based multilevel inverter is presented in this paper for electric and hybrid electric vehicle (EV and HEV) applications. EV systems are quite well for their use of two-level inverters; however, the generated load voltage comprises substantial undesirable harmonic content. It is regarded as one of the most efficient methods since replacing a two-level inverter with a multilevel inverter improves the power quality despite significantly reducing total harmonic distortion. Therefore, the recommended filter dimension will also be minimized. A flurry of reliability concerns has arisen due to the increased number of devices, circuit complexity, and stress on the circuit devices. A nine-level voltage waveform is created with only ten IGBTs, a DC-Source, and two capacitors. In the proposed nine-level inverter, the capacitor voltage is balanced utilizing a simple control approach to regulate the flying capacitor (FC) voltages actively. Here described a simple logic gate-based pulse-width modulation technique that ensures capacitor power balancing. The proposed inverter operation and capability are validated by experimental results derived from a laboratory prototype. Finally, by contrasting the new and standard inverter topologies, the virtues of the suggested architecture by the number of devices and price of the equipment are highlighted, and it is a simpler structure that requires less space and footprint area. © 2022 John Wiley & Sons Ltd.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 single-source nine-level boost inverter with new optimal switching scheme for EV applications(John Wiley and Sons Ltd, 2024) Aditya, K.; Yellasiri, Y.; Shiva Naik, B.; Nageswar Rao, B.; Panda, A.K.The importance of two-level inverters is well known in EV applications; it contains significant unwanted harmonics in generated voltage. One of the most efficient way to increase power quality is to replace a two-level inverter with a multilevel inverter (MLI). The MLI's essence considerably reduces total harmonic distortion. Eventually, the size of the filter requirement also will minimize. Because of the increased device count and capacitor voltage balance issues, these converters have a slew of reliability concerns. To mitigate these drawbacks, a novel switched-capacitor based nine-level inverter (SC-NLI) structure with a new optimal control switching technique for electric vehicle (EV) applications is proposed in this paper. The proposed SC-NLI structure comprises 10 switches, one diode, and two capacitors. The proposed structure's circuit description, modes of operation, proper component selection, and a new optimal switching scheme are presented. A discussion about the comparative analysis of suggested topology with currently developed MLI structures is presented. In addition, to the simulation results, experimental tests are conducted under various load conditions to evaluate the proposed SC-NLI 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 Implementation of novel toroidal transformer-based single-phase multilevel inverter(Springer Science and Business Media Deutschland GmbH, 2024) Nageswar Rao, B.; Yellasiri, Y.; Shiva Naik, B.; Aditya, K.Multilevel inverters (MLIs) have gained traction for their application in high-voltage AC systems and renewable energy. They use fewer DC sources and switches in transformer-based designs to attain the necessary output voltage magnitude. Creating an efficient, high-gain MLI with reduced sources and switches demands meticulous design and substantial effort. This paper introduces a new multilevel inverter design utilizing a toroidal transformer with a reduced number of components. The new topology incorporates ten transistors and a single toroidal transformer. These components are arranged as two H-bridge modules and a bidirectional switch with a transformer to generate nine voltage levels. Notably, the inclusion of three complementary switch pairs in the inverter circuit simplifies the control strategy of the proposed inverter. This configuration enables the inverter to achieve more voltage levels and higher voltage gain using fewer components. Comparison with other existing nine-level inverters highlights the effectiveness of the new design in minimizing the cost function value. The performance assessment of the proposed inverter employs a cost-effective solution. Simulation and experimental results are provided to showcase the practicality and efficiency of the proposed nine-level inverter. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item Design and implementation of novel multilevel inverter with full DC-utilization(Taylor and Francis Ltd., 2025) Nageswar Rao, B.; Yellasiri, Y.; Aditya, K.; Shiva Naik, B.S.; Karunakaran, E.This paper presents a novel single-source transformer-based nine-level (9 L) inverter configuration. The design incorporates a three-level neutral-point-clamped (3 L NPC) inverter, a 3-L full bridge, and a transformer to produce 9 L output voltage levels. In particular, one of the 2 L legs in the full bridge is common among the transformer and the load. The proposed structure minimises the components compared to existing transformer-based nine-level inverters. Thus, the suggested inverter volume, cost, and complexity are minimised. Furthermore, a pulse width modulation method has been developed to generate the necessary gating pulses for the proposed inverter. Additionally, a complete comparison study illustrates the enhanced performance of the suggested architecture. The validity of the suggested 9 L inverter is assessed by performing MATLAB simulations and using a scaled prototype. The results obtained from the simulations and experimental tests are then presented and analysed. A clear correlation was observed between the simulation and the hardware results. © 2024 Informa UK Limited, trading as Taylor & Francis Group.