DocumentCode :
1358798
Title :
A New Multilevel Conversion Structure for Grid-Connected PV Applications
Author :
Grandi, Gabriele ; Rossi, Claudio ; Ostojic, Darko ; Casadei, Domenico
Author_Institution :
Dept. of Electr. Eng., Univ. of Bologna, Bologna, Italy
Volume :
56
Issue :
11
fYear :
2009
Firstpage :
4416
Lastpage :
4426
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 voltage-source 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.
Keywords :
active filters; invertors; photovoltaic power systems; power filters; power generation control; power grids; power transformers; voltage control; control method; dc voltage regulation; digital signal processor; insulated string; maximum power point tracking controller; multilevel conversion structure; multilevel power active filter; numerical simulation; space-vector-modulation algorithm; three-phase grid-connected photovoltaic generation system; three-phase transformer; voltage-source inverter; Multilevel systems; photovoltaic (PV) power systems; power conditioning;
fLanguage :
English
Journal_Title :
Industrial Electronics, IEEE Transactions on
Publisher :
ieee
ISSN :
0278-0046
Type :
jour
DOI :
10.1109/TIE.2009.2029587
Filename :
5226605
Link To Document :
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