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A Modified Hybrid Modulation Strategy for Suppressing DC Voltage Fluctuation of Cascaded H-Bridge Photovoltaic Inverter.

Authors :
Zhao, Tao
Zhang, Xing
Mao, Wang
Wang, Fusheng
Xu, Jun
Gu, Yilei
Source :
IEEE Transactions on Industrial Electronics. May2018, Vol. 65 Issue 5, p3932-3941. 10p.
Publication Year :
2018

Abstract

The hybrid modulation strategy using both low-frequency square-wave modulation and high-frequency pulse-width modulation can extend the stable operating region of a cascaded H-bridge converter. However, it does not control accurately dc voltages of converter but balances them by charging or discharging dc capacitors based on the state of system, which could aggravate fluctuation of dc voltages. If cascaded H-bridge converter is used in photovoltaic field, the aggravated fluctuation on dc capacitor voltages will result in further losses in energy harvesting of solar cells. To address this issue, a modified hybrid modulation strategy is presented in this paper. When dc-bus measured voltages are close to their reference voltages, these H-bridges operate in a zero mode. Adding appropriate zero state can prevent grid current charging or discharging the dc capacitors whose voltages have already reached their control goals. Therefore, the proposed technique is capable of suppressing dc voltage fluctuation, and, thus, improving the output power of solar cells. Simulation and experimental results validate the effectiveness and feasibility of the proposed method. [ABSTRACT FROM PUBLISHER]

Details

Language :
English
ISSN :
02780046
Volume :
65
Issue :
5
Database :
Academic Search Index
Journal :
IEEE Transactions on Industrial Electronics
Publication Type :
Academic Journal
Accession number :
127409160
Full Text :
https://doi.org/10.1109/TIE.2017.2758758