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Fast State-of-Charge-Balancing Strategy for Distributed Energy Storage Units Interfacing with DC–DC Boost Converters

Authors :
Minghang Duan
Jiandong Duan
Quntao An
Li Sun
Source :
Applied Sciences, Vol 14, Iss 3, p 1255 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

State-of-charge balance is vital for allowing multiple energy storage units (ESUs) to make the most of stored energy and ensure safe operation. Concerning scenarios wherein boost converters are used as the interfaces between ESUs and loads, this paper proposes a balancing strategy for realizing consistent state-of-charge (SoC) levels and equal currents among different ESUs. This strategy is valid for both parallel and series applications. Its advantages also include its high precision of SoC equalization without extra sensors and fast convergence. A common outer voltage loop is used to accomplish tight voltage regulation, while multiple inner current loops are utilized to achieve current control and SoC balance simultaneously. Firstly, by introducing SoC-based current distribution ratios (CDRs) to modify current references online, the currents are gradually adjusted to eliminate SoC deviations. Secondly, to expedite the balancing process, current saturations are further adopted. Thirdly, the influences of accelerating factor and current limits in CDR expressions are analyzed, and their selection guidelines are subsequently provided. Fourthly, the controller design, consisting of a dual loop, is illustrated to guarantee sufficient stability margins. Fifthly, an experimental platform consisting of three battery ESUs is developed to verify the proposed strategy.

Details

Language :
English
ISSN :
20763417
Volume :
14
Issue :
3
Database :
Directory of Open Access Journals
Journal :
Applied Sciences
Publication Type :
Academic Journal
Accession number :
edsdoj.0df441b33dc342ce92ff7247747a68e4
Document Type :
article
Full Text :
https://doi.org/10.3390/app14031255