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. 2017 Sep 29;7(1):12396.
doi: 10.1038/s41598-017-12806-5.

A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology

Majid Pakdel  1 , Saeid Jalilzadeh  2
Affiliations

A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology

Majid Pakdel et al. Sci Rep. .

Abstract

In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure1
Figure1
Proposed 3-cell PUC based grid connected inverter.
Figure 2
Figure 2
Proposed (n + 1)-cell PUC based n(n + 1) + 1-level inverter.
Figure 3
Figure 3
One-cycle operating states of the proposed packed U cell based 7-level grid connected inverter.
Figure 4
Figure 4
Control strategy for generating the reference voltage for the proposed PUC based multilevel inverter.
Figure 5
Figure 5
Seven-level sinusoidal modulation.
Figure 6
Figure 6
Proposed modulation method.
Figure 7
Figure 7
Signal S waveform.
Figure 8
Figure 8
Harmonic contents of the output voltage.
Figure 9
Figure 9
Seven level output voltage.
Figure 10
Figure 10
Waveforms of the output voltage vg and load current ig in transient operation.
Figure 11
Figure 11
Experimental prototype of the proposed multilevel grid connected inverter.
Figure 12
Figure 12
7-level output voltage of the proposed 3-cell PUC based grid connected inverter.
See this image and copyright information in PMC

References

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