Four-level double star multilevel converter for grid-connected photovoltaic systems

Sebastian Rivera, Samir Kouro, Ana Llor, Carlos Reusser

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

Medium voltage grids are a suitable selection for the connection of high power applications. However, for certain applications, such as PV energy conversion systems or fast charging stations for PEVs, the DC voltages are limited to be below 1000 V, making difficult their connection to such grids without the use of a step-up transformer. Multilevel converters allow the grid connection of such DC loads, by connecting them in one of their multiple dc sources, however, due the nature of these applications unbalanced operation is inherent, and cannot be completely solved by the modulation stage, thus additional circuitry is required. On the other hand, the use of a multilevel converter provides higher efficiency in the power conversion stage, higher power quality and reduced stress on the switching devices, which is also beneficial due the power ratings being reached by the mentioned applications. This paper explores a four-level double star multilevel converter as interface for central or mul-tistring inverter for grid-connected photovoltaic energy systems. The topology is capable of handling three PV arrays with different MPPT (with or without additional DC-DC converters), with the use of an additional balancing stage. The four-level output voltage improves the power quality of the PV energy conversion system, while reducing the grid filter size. This paper presents the operating principle of the converter, the control scheme and the simulation results, that show this topology can be an interesting alternative for large-scale PV plants.

Original languageEnglish
Title of host publication2017 19th European Conference on Power Electronics and Applications, EPE 2017 ECCE Europe
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9789075815276
DOIs
StatePublished - 6 Nov 2017
Externally publishedYes
Event19th European Conference on Power Electronics and Applications, EPE 2017 ECCE Europe - Warsaw, Poland
Duration: 11 Sep 201714 Sep 2017

Publication series

Name2017 19th European Conference on Power Electronics and Applications, EPE 2017 ECCE Europe
Volume2017-January

Conference

Conference19th European Conference on Power Electronics and Applications, EPE 2017 ECCE Europe
Country/TerritoryPoland
CityWarsaw
Period11/09/1714/09/17

Bibliographical note

Funding Information:
The authors acknowledge the support provided by FONDECYT 1171823, by AC3E (CONI-CYT/Basal/FB0008), and by SERC Chile (CONICYT/FONDAP/15110019)

Publisher Copyright:
© assigned jointly to the European Power Electronics and Drives Association & the Institute of Electrical and Electronics Engineers (IEEE).

Keywords

  • Converter control
  • Multilevel converters
  • Photovoltaic
  • Renewable energy systems

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