The document presents a novel multilevel inverter topology utilizing two variable DC links and a modified H-bridge for low voltage applications, emphasizing reduced components and improved power quality. A comprehensive analysis and comparative study demonstrate that the proposed topology requires fewer switches, gate drivers, and DC sources compared to existing designs, while showing significant reductions in total harmonic distortion. This design is deemed suitable for standalone photovoltaic systems and hybrid electric vehicles, with future plans for hardware implementation.

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A Variable DC Link based Novel Multilevel
Inverter Topology for Low Voltage Applications
ABSTRACT:
In this paper; a variable dc link based novel multilevel inverter (MLI) topology is proposed. This
proposed topology comprises two variable dc links and a modified H-bridge unit. This new
single-phase topology offers advantages such as reduction in count of switches; gate drivers and
dc sources while simultaneously improving the power quality. The proposed topology has been
analyzed for both symmetric and asymmetric modes of operation. A comparative study of the
proposed topology with some recent MLI topologies has been presented. The comparative study
indicates that the proposed topology requires less number of dc sources; switches and driver
circuits as compared to other topologies. The proposed topology has been simulated for 31- level
asymmetric configuration in MATLAB/SIMULINK environment to verify the proper operation
of proposed topology. Harmonic analysis was also performed for 31-level inverter which showed
significant reduction in the total harmonic distortion (THD) for phase voltage and current
waveforms. The proposed topology is suitable for low voltage applications such as standalone
photovoltaic (PV) systems and hybrid electric vehicles (HEVs).
KEYWORDS:
1. Multilevel Inverter
2. Asymmetric Configuration
3. Variable DC Link
4. Reduced Device Count
SOFTWARE: MATLAB/SIMULINK

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CONCLUSION:
In this paper; a novel MLI topology having two variable dc links and a modified H-bridge unit
has been proposed for low voltage applications. Generalized form of proposed topology was
explained for both symmetric and asymmetric modes of operation from the perspective of
quantitative parameters. Through various comparisons made between the proposed asymmetric
topology and other reduced device count topologies; it is concluded that the proposed topology
requires less number of dc sources; switches and gate drivers as compared with the other
presented topologies in literature. However total PIV in proposed topology is found to be slightly
higher as compared with the ACHE topology. On the basis of chosen performance indices;
proposed topology is found to be more economical as compared to their counterparts.
Performance of 31-level proposed asymmetric topology was shown by simulated voltage and
current waveforms. Since the switches T5 and T6 in the modified H-bridge have to withstand the
total output voltage of MLI; these two switches must be of high voltage rating and hence the
proposed topology is best suited for LV applications. The proposed topology also has a
distinctive feature of utilizing asymmetric dc sources in a manner to maintain nearly even
blocking voltage stress across the switches (TJ to T4) in a modified H-bridge. This feature
reduces the number of variety of switches significantly. Harmonic analysis results showed the
significant reduction of harmonics in voltage and current waveforms. So there is no need of filter
circuit to eliminate harmonics. The proposed topology will be beneficial in LV applications such
as standalone PV systems; hybrid electric vehicles (EVs) etc. due to its various benefits. In
future; hardware implementation of the proposed topology will be done.
REFERENCES:
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