Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers

The installation of ultra-fast dc charging infrastructures is rapidly increasing worldwide in response to the exponential growing trend of electric vehicle (EV) market. Due to their discontinuous and unpredictable high power absorption, ultra-fast dc chargers pose a challenge for the power system st...

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Main Authors: Alessandro Roveri, Vincenzo Mallemaci, Fabio Mandrile, Radu Bojoi
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Industry Applications
Subjects:
Online Access:https://ieeexplore.ieee.org/document/10840203/
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author Alessandro Roveri
Vincenzo Mallemaci
Fabio Mandrile
Radu Bojoi
author_facet Alessandro Roveri
Vincenzo Mallemaci
Fabio Mandrile
Radu Bojoi
author_sort Alessandro Roveri
collection DOAJ
description The installation of ultra-fast dc charging infrastructures is rapidly increasing worldwide in response to the exponential growing trend of electric vehicle (EV) market. Due to their discontinuous and unpredictable high power absorption, ultra-fast dc chargers pose a challenge for the power system stability. However, their negative impact on the grid operation can be mitigated by making them bidirectional, leveraging the energy stored in EV batteries or in the installed separate storage. Therefore, the power system can exploit this amount of energy to deal with unexpected grid large power imbalances. Moreover, ultra-fast dc chargers can contribute to power system stability by embedding virtual synchronous machine (VSM) algorithms into their ac/dc stage, i.e., the active front-end (AFE) converter unit. The charging station is thus enabled to provide grid services normally in charge of traditional synchronous generators, such as inertial behavior and short circuit current injection during faults to trigger line protections. However, the provision of inertial active power involves a non-negligible reactive power contribution due to the active-reactive power coupling, thus increasing the output current of the converter. Nevertheless, the power coupling also affects the grid support during faults. Indeed, when the AFE injects a short circuit current into the grid, a fluctuating active power can propagate from the grid to the EVs, resulting in a potential cause of degradation for the EV batteries. Therefore, this article proposes a feedforward-based decoupling solution to guarantee the complete active–reactive power dynamic decoupling while the AFE of an ultra-fast dc charger is providing grid support. Moreover, the proposed method ensures a full-decoupled dynamic response also in case of power references variation during the normal EV charging operation. The proposed decoupling algorithm is experimentally validated on a down-scaled 15 kVA two-level three-phase inverter, emulating the AFE of the ultra-fast dc charger.
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spelling doaj-art-fb63f69edf86406aac8901f4d9fb880f2025-08-20T02:14:51ZengIEEEIEEE Open Journal of Industry Applications2644-12412025-01-01610711910.1109/OJIA.2025.352904210840203Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional ChargersAlessandro Roveri0https://orcid.org/0009-0002-5093-9422Vincenzo Mallemaci1https://orcid.org/0000-0003-1920-7872Fabio Mandrile2https://orcid.org/0000-0002-7769-8078Radu Bojoi3https://orcid.org/0000-0001-7480-5862Prima Electro S.p.A., Moncalieri, ItalyDipartimento Energia, Politecnico di Torino, Torino, ItalyDipartimento Energia, Politecnico di Torino, Torino, ItalyDipartimento Energia, Politecnico di Torino, Torino, ItalyThe installation of ultra-fast dc charging infrastructures is rapidly increasing worldwide in response to the exponential growing trend of electric vehicle (EV) market. Due to their discontinuous and unpredictable high power absorption, ultra-fast dc chargers pose a challenge for the power system stability. However, their negative impact on the grid operation can be mitigated by making them bidirectional, leveraging the energy stored in EV batteries or in the installed separate storage. Therefore, the power system can exploit this amount of energy to deal with unexpected grid large power imbalances. Moreover, ultra-fast dc chargers can contribute to power system stability by embedding virtual synchronous machine (VSM) algorithms into their ac/dc stage, i.e., the active front-end (AFE) converter unit. The charging station is thus enabled to provide grid services normally in charge of traditional synchronous generators, such as inertial behavior and short circuit current injection during faults to trigger line protections. However, the provision of inertial active power involves a non-negligible reactive power contribution due to the active-reactive power coupling, thus increasing the output current of the converter. Nevertheless, the power coupling also affects the grid support during faults. Indeed, when the AFE injects a short circuit current into the grid, a fluctuating active power can propagate from the grid to the EVs, resulting in a potential cause of degradation for the EV batteries. Therefore, this article proposes a feedforward-based decoupling solution to guarantee the complete active–reactive power dynamic decoupling while the AFE of an ultra-fast dc charger is providing grid support. Moreover, the proposed method ensures a full-decoupled dynamic response also in case of power references variation during the normal EV charging operation. The proposed decoupling algorithm is experimentally validated on a down-scaled 15 kVA two-level three-phase inverter, emulating the AFE of the ultra-fast dc charger.https://ieeexplore.ieee.org/document/10840203/Active front-ends (AFEs)electric vehicles (EVs)grid servicesgrid supportpower decouplingpower system stability
spellingShingle Alessandro Roveri
Vincenzo Mallemaci
Fabio Mandrile
Radu Bojoi
Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
IEEE Open Journal of Industry Applications
Active front-ends (AFEs)
electric vehicles (EVs)
grid services
grid support
power decoupling
power system stability
title Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
title_full Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
title_fullStr Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
title_full_unstemmed Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
title_short Power Decoupling Methods for Grid Support Provided by Ultra-Fast Bidirectional Chargers
title_sort power decoupling methods for grid support provided by ultra fast bidirectional chargers
topic Active front-ends (AFEs)
electric vehicles (EVs)
grid services
grid support
power decoupling
power system stability
url https://ieeexplore.ieee.org/document/10840203/
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AT fabiomandrile powerdecouplingmethodsforgridsupportprovidedbyultrafastbidirectionalchargers
AT radubojoi powerdecouplingmethodsforgridsupportprovidedbyultrafastbidirectionalchargers