ABSTRACT:
This paper investigates the modern topology of multilevel
converters, which are suitable for use in high power photovoltaic applications
with the focus on achieving lower total harmonic distortion and better
efficiency. Multilevel converters offer several advantages compared to
conventional types. Multilevel converters provide high quality output while
using the low switching frequency. It affects the switching losses, size of semiconductor
switches and harmonic filters. This research investigates various topologies of
multilevel converter for high power photovoltaic applications and compares
their THD, efficiency, number of required semiconductors and other important
characteristics. All topologies are simulated using MATLAB/Simulink in the same
operating conditions. Finally, the more suitable multilevel topology is selected
with respect to the simulation results.
KEYWORDS:
1.
Photovoltaic
2.
Multilevel converter
3.
Qualitative study
4.
High power application
SOFTWARE: MATLAB/SIMULINK
DIFFERENT TOPOLOGIES:
Fig
1: a) NPC b) Capacitor clamped c) Cascade d) Z-source e) Quasi Z-source f)
Hybrid
EXPECTED SIMULATION RESULTS:
Fig.2.
Three level NPC inverter voltage and current waveforms.
Fig.
3. Three level Capacitor clamped voltage and current waveforms.
Fig.
4. Voltage and current waveforms of three level cascaded inverter.
Fig.5. Voltage and current waveforms of three level Z
source inverter.
Fig.6. Voltage and current waveforms of three level
Quasi Z source.
Fig.
7. Voltage and current waveforms of three level hybrid model.
CONCLUSION:
The
price analysis of the converter shows that multilevel converters are more
economic than conventional types in the case of medium and high power
applications. In This research, different multilevel converter topologies have
been investigated and compared in order to find the most suitable topology,
which is appropriate to use in the PV applications. Six multilevel topologies,
which were proposed in the literature, have been investigated. The
investigation was done via quantitative and qualitative study. In quantitative
study, important output parameters of proposed multilevel topologies were
evaluated using Matlab/Simulink at the same operating point. Also, a qualitative
analysis has been performed to investigate some advantages and disadvantages of
each topology, which cannot be considered in the simulation. The results prove
that quasi Z-source converter has better performance in comparison with other
types.
REFERENCES:
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