A novel scheme for three-phase grid-connected photovoltaic (PV) generation systems is presented in this paper. The scheme is based on two insulated strings of PV panels, each one feeding the dc bus of a standard two-level three-phase voltagesource inverter (VSI). The inverters are connected to the grid by a three-phase transformer having open-end windings on the inverter side. The resulting conversion structure performs as a multilevel power active filter (equivalent to a three-level inverter), doubling the power capability of a single VSI with given voltage and current ratings. The multilevel voltage waveforms are generated by an improved space-vector-modulation algorithm, suitable for the implementation in industrial digital signal processors. An original control method has been introduced to regulate the dc-link voltages of each VSI, according to the voltage reference given by a single maximum power point tracking controller. The proposed regulation system has been verified by numerical simulations and experimental tests with reference to different operating conditions.
Titolo: | A New Multilevel Conversion Structure for Grid-Connected PV Applications |
Autore/i: | GRANDI, GABRIELE; D. Ostojic; ROSSI, CLAUDIO; CASADEI, DOMENICO |
Autore/i Unibo: | |
Anno: | 2009 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1109/TIE.2009.2029587 |
Abstract: | A novel scheme for three-phase grid-connected photovoltaic (PV) generation systems is presented in this paper. The scheme is based on two insulated strings of PV panels, each one feeding the dc bus of a standard two-level three-phase voltagesource inverter (VSI). The inverters are connected to the grid by a three-phase transformer having open-end windings on the inverter side. The resulting conversion structure performs as a multilevel power active filter (equivalent to a three-level inverter), doubling the power capability of a single VSI with given voltage and current ratings. The multilevel voltage waveforms are generated by an improved space-vector-modulation algorithm, suitable for the implementation in industrial digital signal processors. An original control method has been introduced to regulate the dc-link voltages of each VSI, according to the voltage reference given by a single maximum power point tracking controller. The proposed regulation system has been verified by numerical simulations and experimental tests with reference to different operating conditions. |
Data prodotto definitivo in UGOV: | 2009-12-21 18:42:24 |
Appare nelle tipologie: | 1.01 Articolo in rivista |