Five-level T-type cascade converter for rooftop grid-connected photovoltaic systems
Multilevel converters are widely considered to be the most suitable configurations for renewable energy sources. Their high-power quality, efficiency and performance make them interesting for PV applications. In low-power applications such as rooftop grid-connected PV systems, power converters with...
| Autores: | , , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2019 |
| País: | España |
| Recursos: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/134223 |
| Acesso em linha: | https://hdl.handle.net/2117/134223 https://dx.doi.org/10.3390/en12091743 |
| Access Level: | acceso abierto |
| Palavra-chave: | Electric current converters Photovoltaic power systems Convertidors de corrent elèctric Energia solar fotovoltaica Àrees temàtiques de la UPC::Enginyeria electrònica::Electrònica de potència::Convertidors de corrent elèctric Àrees temàtiques de la UPC::Energies::Energia elèctrica::Automatització i control de l'energia elèctrica Àrees temàtiques de la UPC::Energies::Energia solar fotovoltaica |
| Resumo: | Multilevel converters are widely considered to be the most suitable configurations for renewable energy sources. Their high-power quality, efficiency and performance make them interesting for PV applications. In low-power applications such as rooftop grid-connected PV systems, power converters with high efficiency and reliability are required. For this reason, multilevel converters based on parallel and cascaded configurations have been proposed and commercialized in the industry. Motivated by the features of multilevel converters based on cascaded configurations, this work presents the modulation and control of a rooftop single-phase grid-connected photovoltaic multilevel system. The configuration has a symmetrical cascade connection of two three-level T-type neutral point clamped power legs, which creates a five-level converter with two independent string connections. The proposed topology merges the benefits of multi-string PV and symmetrical cascade multilevel inverters. The switching operation principle, modulation technique and control scheme under an unbalanced power operation among the cell are addressed. Simulation and experimental validation results in a reduced-scale power single-phase converter prototype under variable conditions at different set points for both PV strings are presented. Finally, a comparative numerical analysis between other T-type configurations to highlight the advantages of the studied configuration is included. |
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