Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization

The modular multilevel converter with embedded supercapacitor energy storage system (MMC-SCES) is a promising solution to the integration challenges posed by large-scale renewable energy. However, inconsistencies in supercapacitor characteristics across energy storage submodules (ESMs) can lead to s...

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Main Authors: Qiluan Yang, Huangqing Xiao, Qionghai Zhu
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/10/5331
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author Qiluan Yang
Huangqing Xiao
Qionghai Zhu
author_facet Qiluan Yang
Huangqing Xiao
Qionghai Zhu
author_sort Qiluan Yang
collection DOAJ
description The modular multilevel converter with embedded supercapacitor energy storage system (MMC-SCES) is a promising solution to the integration challenges posed by large-scale renewable energy. However, inconsistencies in supercapacitor characteristics across energy storage submodules (ESMs) can lead to state-of-charge (SOC) imbalances, reducing overall energy storage utilization. To address this challenge, this paper proposes an enhanced SOC balancing control strategy that leverages the inherent correlation between SOC and submodule capacitor voltage. The strategy simultaneously regulates both energy storage power and ESM capacitor voltage to maintain balance. A two-terminal transmission system with MMC-SCES is built in PSCAD/EMTDC. The results demonstrated that the proposed strategy achieved SOC balancing with only six centralized energy storage controllers, while the SOC balancing of the ESMs remained independent of the startup time. The implementation of the reduced switching frequency voltage balancing algorithm reduced the average switching frequency by 94.54% while maintaining the maximum SOC difference below 0.50%. Moreover, the adaptive coefficients improved the balancing speed by approximately 15% and reduced the initial circulating current by approximately 25%.
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publishDate 2025-05-01
publisher MDPI AG
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spelling doaj-art-09b53ce1d6d644b3be45fb9441f7a95e2025-08-20T03:14:45ZengMDPI AGApplied Sciences2076-34172025-05-011510533110.3390/app15105331Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive OptimizationQiluan Yang0Huangqing Xiao1Qionghai Zhu2School of Electric Power Engineering, South China University of Technology, Guangzhou 510641, ChinaSchool of Electric Power Engineering, South China University of Technology, Guangzhou 510641, ChinaSchool of Electric Power Engineering, South China University of Technology, Guangzhou 510641, ChinaThe modular multilevel converter with embedded supercapacitor energy storage system (MMC-SCES) is a promising solution to the integration challenges posed by large-scale renewable energy. However, inconsistencies in supercapacitor characteristics across energy storage submodules (ESMs) can lead to state-of-charge (SOC) imbalances, reducing overall energy storage utilization. To address this challenge, this paper proposes an enhanced SOC balancing control strategy that leverages the inherent correlation between SOC and submodule capacitor voltage. The strategy simultaneously regulates both energy storage power and ESM capacitor voltage to maintain balance. A two-terminal transmission system with MMC-SCES is built in PSCAD/EMTDC. The results demonstrated that the proposed strategy achieved SOC balancing with only six centralized energy storage controllers, while the SOC balancing of the ESMs remained independent of the startup time. The implementation of the reduced switching frequency voltage balancing algorithm reduced the average switching frequency by 94.54% while maintaining the maximum SOC difference below 0.50%. Moreover, the adaptive coefficients improved the balancing speed by approximately 15% and reduced the initial circulating current by approximately 25%.https://www.mdpi.com/2076-3417/15/10/5331supercapacitor energy storagebidirectional DC/DC convertermodular multilevel converterstate-of-charge balancingcentralized controladaptive optimization
spellingShingle Qiluan Yang
Huangqing Xiao
Qionghai Zhu
Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
Applied Sciences
supercapacitor energy storage
bidirectional DC/DC converter
modular multilevel converter
state-of-charge balancing
centralized control
adaptive optimization
title Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
title_full Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
title_fullStr Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
title_full_unstemmed Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
title_short Enhanced State-of-Charge Balancing Control for MMC-SCES Using Centralized Controllers and Adaptive Optimization
title_sort enhanced state of charge balancing control for mmc sces using centralized controllers and adaptive optimization
topic supercapacitor energy storage
bidirectional DC/DC converter
modular multilevel converter
state-of-charge balancing
centralized control
adaptive optimization
url https://www.mdpi.com/2076-3417/15/10/5331
work_keys_str_mv AT qiluanyang enhancedstateofchargebalancingcontrolformmcscesusingcentralizedcontrollersandadaptiveoptimization
AT huangqingxiao enhancedstateofchargebalancingcontrolformmcscesusingcentralizedcontrollersandadaptiveoptimization
AT qionghaizhu enhancedstateofchargebalancingcontrolformmcscesusingcentralizedcontrollersandadaptiveoptimization