Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems

Compared to the AC counterpart, the DC shore power system provides a significant advantage of efficient power supply from renewable sources to ships and onshore loads. Super-capacitors serve as key energy storage units in such a system to buffer the power fluctuations and collect the regenerative en...

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Main Authors: Wenqiang Xie, Mingming Shi, Yuying He, Chenyu Zhang, Ruihuang Liu
Format: Article
Language:English
Published: MDPI AG 2024-09-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/17/18/4630
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author Wenqiang Xie
Mingming Shi
Yuying He
Chenyu Zhang
Ruihuang Liu
author_facet Wenqiang Xie
Mingming Shi
Yuying He
Chenyu Zhang
Ruihuang Liu
author_sort Wenqiang Xie
collection DOAJ
description Compared to the AC counterpart, the DC shore power system provides a significant advantage of efficient power supply from renewable sources to ships and onshore loads. Super-capacitors serve as key energy storage units in such a system to buffer the power fluctuations and collect the regenerative energy. However, the ultra-wide voltage range of super-capacitors imposes a significant challenge in the topology selection and efficiency optimization of the interfacing isolated bidirectional DC–DC converter. To tackle this challenge, this paper analyzes and compares two promising converter topologies, which are a configurable modular two-level dual-active bridge (CM-2L-DAB) and a three-level dual-active bridge (3L-DAB). To facilitate an ultra-wide voltage range, extended phase-shift (EPS) modulation in conjunction with the topology reconfiguration is analyzed for the CM-2L-DAB, while a hybrid modulation scheme is proposed for the 3L-DAB. A unified design approach is provided for both topologies, which also yields to the power loss modeling. On this basis, the CM-2L-DAB and 3L-DAB are thoroughly compared in terms of the modulation schemes, current stress, soft-switching operation, power conversion efficiency, material usage, closed-loop control scheme, and reliability. A prominent conclusion can be drawn that the CM-2L-DAB provides a higher efficiency than the 3L-DAB over the whole voltage range, but it relies on additional relays to reconfigure its topology which results in lower reliability and dynamic performance than the 3L-DAB.
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spelling doaj-art-040b643837fa492f9ab4db8701db5e4e2025-08-20T01:55:30ZengMDPI AGEnergies1996-10732024-09-011718463010.3390/en17184630Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power SystemsWenqiang Xie0Mingming Shi1Yuying He2Chenyu Zhang3Ruihuang Liu4State Grid Electric Power Research Institute of Jiangsu Province, Nanjing 210003, ChinaState Grid Electric Power Research Institute of Jiangsu Province, Nanjing 210003, ChinaCollege of Electrical and Power Engineering, Hohai University, Nanjing 211100, ChinaState Grid Electric Power Research Institute of Jiangsu Province, Nanjing 210003, ChinaState Grid Electric Power Research Institute of Jiangsu Province, Nanjing 210003, ChinaCompared to the AC counterpart, the DC shore power system provides a significant advantage of efficient power supply from renewable sources to ships and onshore loads. Super-capacitors serve as key energy storage units in such a system to buffer the power fluctuations and collect the regenerative energy. However, the ultra-wide voltage range of super-capacitors imposes a significant challenge in the topology selection and efficiency optimization of the interfacing isolated bidirectional DC–DC converter. To tackle this challenge, this paper analyzes and compares two promising converter topologies, which are a configurable modular two-level dual-active bridge (CM-2L-DAB) and a three-level dual-active bridge (3L-DAB). To facilitate an ultra-wide voltage range, extended phase-shift (EPS) modulation in conjunction with the topology reconfiguration is analyzed for the CM-2L-DAB, while a hybrid modulation scheme is proposed for the 3L-DAB. A unified design approach is provided for both topologies, which also yields to the power loss modeling. On this basis, the CM-2L-DAB and 3L-DAB are thoroughly compared in terms of the modulation schemes, current stress, soft-switching operation, power conversion efficiency, material usage, closed-loop control scheme, and reliability. A prominent conclusion can be drawn that the CM-2L-DAB provides a higher efficiency than the 3L-DAB over the whole voltage range, but it relies on additional relays to reconfigure its topology which results in lower reliability and dynamic performance than the 3L-DAB.https://www.mdpi.com/1996-1073/17/18/4630isolated bidirectional DC–DC converterswide voltage rangemodulation schemecomparison
spellingShingle Wenqiang Xie
Mingming Shi
Yuying He
Chenyu Zhang
Ruihuang Liu
Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
Energies
isolated bidirectional DC–DC converters
wide voltage range
modulation scheme
comparison
title Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
title_full Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
title_fullStr Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
title_full_unstemmed Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
title_short Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems
title_sort comparison of configurable modular two level and three level isolated bidirectional dc dc converters for super capacitor charging in dc shore power systems
topic isolated bidirectional DC–DC converters
wide voltage range
modulation scheme
comparison
url https://www.mdpi.com/1996-1073/17/18/4630
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