Faculty Publications
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Item Five-Level Switched Capacitor Inverter for Photovoltaic Applications(Taylor and Francis Ltd., 2022) Singh, A.K.; Mandal, R.K.; Raushan, R.; Anand, R.This paper proposes a switched-capacitor based single-phase five-level inverter configuration that operates under boost operation and generates a voltage that is more than the DC source voltage. The proposed five-level inverter uses a capacitor and boots the output voltage. In this proposed inverter, capacitor gets charged in parallel while it discharges in series connections so that output voltage may attain higher magnitude than the DC source voltage. Sinusoidal Pulse Width Modulation-based techniques are considered to produce the required gate pulses for operating the switching devices of the inverter. The five-level switched-capacitor inverter is combined with the PV system via DC–DC boost converters to extract the maximum power using MPPT algorithm. To verify its capability, the PV-based system is further integrated to the utility grid. The operation and performance of the suggested switched-capacitor inverter coupled with the grid-connected PV system are also analyzed by developing its model in MATLAB/Simulink environment. © 2022 IETE.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.Item A Novel Two Five-Level Double-Boost Inverters for Grid-Tied Photovoltaic Applications(Springer, 2025) Maheswari, G.; Manjunatha Sharma, K.M.; P, P.This paper proposes two novel five-level inverters, both featuring a common ground configuration and double-boosting capability. The common ground configuration in the proposed topologies effectively eliminates leakage current, making them ideal for grid-connected photovoltaic applications. The first proposed inverter topology consists of a single DC source, six power switches, two diodes, two capacitors, and one charging inductor. The second topology also uses a single DC source but comprises seven power switches, one diode, two capacitors, and one charging inductor. In both proposed inverter topologies, the switched capacitors automatically balance to voltages of Vdc and 2Vdc. Additionally, the charging inductor helps reduce spike currents in the capacitor charging path. These inverters offer several advantages, including a reduced component count, low per-unit total standing voltage, high efficiency, increased power density due to fewer components, reduced spike currents, and a common ground (CG) structure that entirely eliminates leakage current. The proposed inverters employ a proportional-integral (PI) controller with phase disposition pulse-width modulation (for the first converter) and staircase modulation (for the second converter). A comparative analysis of existing and proposed five-level inverters is presented, demonstrating their suitability for grid-tied photovoltaic applications through MATLAB Simulink simulations and experimental validation using Hardware-in-the-Loop (HIL). © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.