Faculty Publications
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Item 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 A Fuzzy Logic Based Switching Methodology for a Cascaded H-Bridge Multi-Level Inverter(Institute of Electrical and Electronics Engineers Inc., 2019) Azeem, H.; Yellasiri, Y.; Jammala, V.; Shiva Naik, B.S.; Panda, A.K.In this letter, an unusual switching technique is implemented using a fuzzy logic approach. The proposed technique simplifies the conventional method by eliminating the traditional logic-gate design. The fuzzy logic pulse generator acts as a lookup table as well as a pulse generator. On the basis of the modulation index as input, controlled membership functions (MFs) and rules of the fuzzy logic controller open various possibilities of producing pulses directly. The proposed technique is evaluated on the cascaded multi-level inverter with symmetric and asymmetric operations using selective harmonic elimination pulsewidth modulation. MFs are designed on the basis of pre-calculated firing conditions for different modulation index values. Hardware verification is carried out to support the proposed switching technique. © 1986-2012 IEEE.Item Development of cascaded multilevel inverter based active power filter with reduced transformers(China Power Supply Society, 2020) Nageswar Rao, B.N.; Yellasiri, Y.; Panda, A.K.; Shiva Naik, B.S.; Jammala, V.Active power filter is a power electronic converter used for improving the quality of supply by eliminating the effect of harmonics due to non-linear loads. This paper recommends a concept for shunt active power filter (SAPF) using a single power source fed to a cascaded multilevel inverter (CMI) with 3-? transformers. Apart from traditional transformer based topologies, the required number of transformers are substantially reduced, resulting in less space requirement, which leads to low cost and simple control system. The proposed CMI based SAPF has a capacity to compensate for contaminated load with high harmonic and a low power factor. The effective id ? iq theory is used to calculate compensation currents. DC link voltage regulator analyzed through delay time and controller gain. The tasks of the controller in the SAPF can perform all necessary actions for correct operation in SAPF. A wide range of computer simulation results demonstrated and validated the results with the prototype experimental setup. © 2021 All rights reserved.Item A Hybrid Nine-Level Inverter Topology with Boosting Capability and Reduced Component Count(Institute of Electrical and Electronics Engineers Inc., 2021) Shiva Naik, B.S.; Yellasiri, Y.; Venkataramanaiah, J.; Panda, A.K.Nowadays, output voltage boosting gain property along with curtailment in the circuit voltage stress, and component count are considered as the essential topological features for the new multilevel inverter (MLI) circuits. Recognizing the above, a hybrid nine-level inverter topology (HNIT) for DC-AC conversion is proposed in this brief. Each phase of the HNIT is designed with only eight semiconductor switches, one diode, and two electrolytic capacitors. Herein, series-parallel and conventional-series techniques are utilized effectively to balance the capacitor voltages. Further, cost and quantitative comparisons are carried among the state-of-art circuits to highlight the supremacy of proposed circuit. Subsequently, the performance of HNIT is verified experimentally with the fundamental switching PWM technique at different load conditions. © 2004-2012 IEEE.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 Novel Quadruple Boost Inverter With New Optimized Fuzzy-Based Switching Scheme(Institute of Electrical and Electronics Engineers Inc., 2024) Aditya, K.; Yellasiri, Y.; Shiva Naik, B.S.; Nageswar Rao, B.N.; Panda, A.K.This brief proposes a novel quadruple boost nine-level inverter (QB-NLI) and an optimized switching pattern using fuzzy logic controller. The suggested method simplifies the traditional approach by removing the conventional logic gate circuit design. The pulse signal generator and lookup table are both derived using a fuzzy logic pulse generator. Fuzzy logic controller (FLC) and Controlled membership functions (MFs) rules open numerous prospects for generating pulses based on the input as modulation index. The suggested technique is examined on the proposed QB-NLI topology using the selective harmonic elimination PWM method. MFs are created based on averaging Newton Rapson and quantizer firing angles for diverse modulation index (mi) values. The proposed QB-NLI structure comprises ten switches with one dc-voltage source and two capacitors. The proposed structure's circuit description, modes of operation, proper component selection, and a new fuzzy-based switching scheme are presented. Further, a discussion about the comparative analysis of the proposed switching technique with other switching techniques concerning THD and RMS voltages is presented. In addition to the simulation results, experimental tests are conducted under various load conditions on the built-in hardware prototype to evaluate the proposed QB-NLI structure and switching technique. © 2023 IEEE.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.