Browsing by Author "Jammala, V."

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    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.
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    Development of a New Hybrid Multilevel Inverter Using Modified Carrier SPWM Switching Strategy
    (2018) Jammala, V.; Yellasiri, S.; 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.
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    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.
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    A Fuzzy Logic Based Switching Methodology for a Cascaded H-Bridge Multi-Level Inverter
    (2019) Azeem, H.; Yellasiri, S.; Jammala, V.; 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.