Faculty Publications
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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 Investigation on stacked cascade multilevel inverter by employing single-phase transformers(Elsevier B.V., 2016) Yellasiri, Y.; Panda, A.K.In the present paper a new version of multilevel inverter is investigated. This new version is based on hybrid association of commutation cells with H-bridge cells. The association allows a significant reduction of the volume of the capacitors. In fact, presented topology allows us to work on higher input voltage levels with the same power switches. This new version is generally called as SCMI (stacked cascade multilevel inverter). The proposed inverter has potential to generate high quality waveforms, reduction in switching frequency, capable to operate at higher voltage levels and finally utilizes minimum number of switching components. The presented version of SCMI is simulated in Matlab-simulink and further, experimental validation is carried out in the laboratory with prototype setup. © 2016 Karabuk 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 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 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 2019