Article
Green & Sustainable Science & Technology
Yi Wang, Yuwei Li, Chen Wang, Jianye Tao
Summary: This paper proposes a hybrid arm-multiplexing modular multilevel converter (HAM-MMC), considering both the DC fault ride-through (FRT) and lightweight requirements of MMC. The time-division multiplexing of middle arms between upper and lower arms is achieved by introducing arm selection switches, which considerably enhances the submodule utilization and thus minimizes the submodule number. Simulation results demonstrate that the proposed HAM-MMC can smoothly ride through DC voltage dip without interrupting power transmission, and can also rapidly resume normal operation after a zero-voltage disturbance.
IET RENEWABLE POWER GENERATION
(2023)
Article
Engineering, Electrical & Electronic
Ewan M. Farr, Ralph Feldman, Jon C. Clare, Omar F. Jasim
Summary: This article introduces ac fault ride-through strategies for the extended-overlap operating mode of the alternate arm converter, which are experimentally validated. The AAC offers benefits such as requiring fewer submodules with smaller capacitance compared to the half-bridge modular multilevel converter, and providing dc fault ride-through capability.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Yanxun Guo, Haifeng Li, Guangkun Gu, Dehui Zeng, Gang Wang
Summary: DC circuit breakers (DCBs) are used to isolate faults in high-voltage DC grids. Multiple DCBs connected to multiple lines form a DCB cluster, which can be integrated into a multiport DCB (MDCB) to reduce construction costs. This article proposes a novel MDCB to integrate current-injection-DCBs (C-DCBs) for improved interruption reliability. The proposed MDCB is compared with traditional DCB clusters and previous MDCBs to show economic and reliability advantages, and is validated using simulations.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Binbin Li, Bingxu Zhang, Yujie Zhang, Lei Li, Dianguo Xu
Summary: This article presents a thyristor-submodule hybrid dc/dc converter (TSDC) that combines the advantages of low cost, low conduction loss, and high robustness of thyristors with the high controllability of cascaded half-bridge submodules. The TSDC offers efficient dc/dc conversion, reliable thyristor switching, wide voltage operation range, and the ability to block dc faults without the need for dc circuit breakers.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Mian Wang, Mario Zaja, Jef Beerten, Dragan Jovcic, Dirk Van Hertem
Summary: This paper investigates the breaker failure backup protection algorithm for HVDC grid protection and proposes a new backup protection algorithm that can accurately and rapidly detect both complete and partial failures of breakers. The algorithm detects breaker failures by estimating the counter-voltage created by the energy absorption branch.
IEEE TRANSACTIONS ON POWER DELIVERY
(2021)
Article
Engineering, Electrical & Electronic
Yunting Liu, Fang Z. Peng
Summary: This article presents a DC capacitor-less Solid State Variable Capacitor (SSVC) which removes bulky DC capacitors used in traditional systems, simplifying the structure and improving reliability. By utilizing AC-side voltage to support DC voltage, this innovative approach only requires a small capacitor for filtering, enabling the removal of other capacitors from the DC link busbar.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Xiuyan Wei, Guibin Zou, Shuo Zhang, Chengquan Zhang
Summary: This paper proposes an adaptive reclosing scheme for flexible DC grids to prevent power supply interruption caused by temporary faults. The scheme analyzes the disconnected pole coupling voltage under the total electric field and constructs a fault property identification criterion based on the difference between permanent faults and temporary faults. Extensive simulations and experiments verify the effectiveness of the proposed strategy.
IET GENERATION TRANSMISSION & DISTRIBUTION
(2023)
Article
Computer Science, Information Systems
Roberto Benato, Giovanni Gardan
Summary: This paper generalizes the matrix algorithm PFPD for computing power flow solutions in real and large AC/DC transmission networks. It demonstrates that HVDC-VSC/LCC links can be viewed as PV/PQ constraints, encompassing both AC and DC characteristics. The algorithm is also capable of estimating the reactive power absorption of HVDC-LCC links.
Article
Computer Science, Information Systems
Songyuan Cao, Lingzhi Xia, Diwen Tao, Yang Cheng, Shenghu Li
Summary: This study introduces a power optimization method to address the angular oscillation issue in high-voltage DC power systems with synchronous generators. By incorporating trajectory sensitivity and an imbalanced matrix derived from time-domain simulation, this method optimizes system stability and reduces the objective function and oscillation amplitude.
Article
Engineering, Electrical & Electronic
Oriol Gomis-Bellmunt, Enric Sanchez-Sanchez, Josep Arevalo-Soler, Eduardo Prieto-Araujo
Summary: The paper discusses the increasing significance of segmented AC power systems interconnected by HVDC, and the need to define the governing roles of Interconnecting Power Converters (IPC) connecting different subgrids. Various operation modes of IPC are presented and analyzed, along with principles of operation for each subgrid and the overall system. Fundamental equations are outlined and integrated into a power flow formulation, with a case study illustrating the power flow formulation and dynamic simulations of transitions between operating points in a grid of multiple subgrids.
IEEE TRANSACTIONS ON POWER DELIVERY
(2021)
Article
Energy & Fuels
Daniel L. Gerber, Fariborz Musavi, Omkar A. Ghatpande, Stephen M. Frank, Jason Poon, Richard E. Brown, Wei Feng
Summary: This study derived loss models of DC/DC and AC/DC PFC boost converters with identical components, showing that DC boost converters are more efficient than AC boost converters. Though boost converters are a small fraction of electronics in buildings, these loss models can lay the foundation for a comprehensive analysis based on full-building models.
Article
Engineering, Electrical & Electronic
Mohd Shadab Ansari, Anshuman Shukla, Himanshu J. Bahirat
Summary: This article introduces the extended overlap modulation technique in MMDC to reduce the need for dc-link filters. The change in overlap angle affects the conduction states, component sizing, harmonic spectrum, and other converter parameters. Simulation and analytical studies analyze the effect of change in overlap duration on the size of submodule capacitor and dc-link filter. A single-stage three-phase MMC experimental setup is built to verify the converter operation in both SO and EO modulations.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Dimitrios Vozikis, Fahad Alsokhiry, Grain Philip Adam
Summary: An improved two-level converter, I2LC, is presented as a practical design trade-off between conventional two-level converter (C2LC) and modular multilevel converter (MMC), focusing on AC and DC fault responses similar to MMC and simplicity of C2LC. The theoretical analysis and validation through scaled-down simulations and experiments show that I2LC can achieve concurrent operational objectives during unbalanced AC grid conditions. Further investigation on the performance during asymmetrical AC faults supports the theoretical analysis and experimental studies.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2021)
Article
Engineering, Multidisciplinary
Ricardo Granizo, Jose Guerrero, Fernando Alvarez, Carlos Platero
Summary: This article presents a new protection method for ground faults in multiterminal HVdc networks, which involves measuring and analyzing the current polarity in the grounded shields of HVdc cables to quickly and accurately detect and disconnect ground faults. The proposed method has been successfully validated through computer simulations and laboratory tests.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Computer Science, Information Systems
Mehedi Hassan, M. Jahangir Hossain, Rakibuzzaman Shah
Summary: The study presents a fault identification technique based on reactor voltage gradient for fast and precise discrimination of internal and external DC faults, enhancing protection reliability through main and backup protection schemes. The proposed method is validated in a four-terminal MTDC grid, showing high selectivity for various fault resistances and locations, increased sampling frequencies, and irrelevant transient events, making it a superior choice for future DC fault identification.
Article
Engineering, Electrical & Electronic
Willem Leterme, Paul D. Judge, James Wylie, Tim C. Green
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2020)
Article
Engineering, Electrical & Electronic
Sohail G. Mian, Paul D. Judge, Adri Junyent-Ferr, Tim C. Green
Summary: This paper presents a delta-connected Modular Multilevel STATCOM with partially rated storage (PRS-STATCOM) that can provide short-term energy storage enabled grid support services. A control structure has been developed to allow energy transfer and active power exchange between standard sub-modules (STD-SMs) and energy storage element sub-modules (ESE-SMs), reducing the required ESE-SMs fraction effectively.
IEEE TRANSACTIONS ON POWER DELIVERY
(2021)
Article
Engineering, Electrical & Electronic
Pablo Poblete, German Pizarro, Gabriel Droguett, Felipe Nunez, Paul D. Judge, Javier Pereda
Summary: Modular multilevel converters (MMCs) are popular power converters for medium/high-power transmission systems and motor drive applications. However, the standard control schemes for MMCs require a large number of sensors and the communication of sensitive data, which can be affected by electromagnetic interference (EMI), thus impacting the reliability and cost of the MMC. This paper proposes a distributed neural network (DNN) observer to estimate the capacitor voltages at each submodule (SM) of the MMC, reducing the number of required sensors and improving performance through noise filtering.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Review
Energy & Fuels
Sohail Sarwar, Desen Kirli, Michael M. C. Merlin, Aristides E. Kiprakis
Summary: This article reviews recent literature on the stability, management, and control strategies of AC/DC hybrid microgrids (HMG). Power flow analysis, power sharing, global control of distributed generation, and the complexity of HMG protection plans are examined. The review highlights the common techniques used in HMG control and identifies the challenges and limitations that need to be addressed for sustainable operation.
Article
Engineering, Electrical & Electronic
Sebastian Neira, Zoe Blatsi, Paul D. D. Judge, Michael M. C. Merlin, Javier Pereda
Summary: In this paper, the integration of partially rated energy storage systems (ESS) into modular multilevel converter (MMC) substations using parallel branches to the arm inductors is presented. The proposed ESS-MMC topology does not modify the original MMC design but adds partially rated ESS with electrical connections outside the valve hall. The system utilizes another frequency component in the arm circulating current to exchange power between the energy storage branches and the original MMC stacks. Control algorithms are developed to maximize the power flow capabilities from the ESS while maintaining operational limits.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Zoe Blatsi, Paul D. Judge, Stephen J. Finney, Michael Marc Claude Merlin
Summary: This paper discusses the blackstart provision enabled by Modular Multilevel Converters (MMC) with integrated partially-rated Energy Storage (ES) systems. It demonstrates the utilization of ES units in an MMC to charge converter capacitors, supply voltage at ac and dc terminals, and energize the power supply electronics of the submodules during converter start-up, making it useful in passive grids or after disconnection events. The added functionality of charging the converter capacitors and starting up adjacent networks requires no additional infrastructure for an MMC with integrated ES, only an updated control scheme. Simulation results confirm the effectiveness of the method, with a fully disconnected MMC charging within 2 seconds and connecting to a passive ac network, supplying 5% of active and reactive power with only 4% of ES-SMs per stack.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Mason Parker, Ilker Sahin, Ross Mathieson, Stephen Finney, Paul D. Judge
Summary: Silicon Carbide MOSFETs have lower switching losses compared to Silicon IGBT with similar ratings, but they have faster switching speeds, larger overshoots, and increased oscillatory switching behavior, resulting in greater EMI generation. Active Gate Drivers (AGD) can mitigate these issues while maintaining low switching losses. This paper presents an experimental investigation into the influence of different AGD capabilities on switching performance of a high current module, aiming to guide future AGD designers on the trade-offs between signal resolution and complexity. The results show that higher resolution (2.5-5 ns) provides the greatest improvements in switching performance, even with simpler gate driving patterns, while more complex patterns offer minimal additional improvements. However, at lower timing resolutions (10-40 ns), simpler gate patterns result in a stronger degradation of switching performance, which can be mitigated by using more complex patterns.
IEEE OPEN JOURNAL OF POWER ELECTRONICS
(2023)
Proceedings Paper
Energy & Fuels
Chuantong Hao, Wenhao Ma, Michael Merlin, Paul Judge, Stephen Finney
Summary: This paper presents a modular multilevel STATCOM with partially rated energy storage, which is configured based on a full bridge multi busbar Sub-module (SM). The performance of the proposed topology is compared with a conventional single-busbar full bridge STATCOM. The results show that the proposed MBSM STATCOM reduces power losses and SM voltage deviation, while improving power factor.
2022 24TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'22 ECCE EUROPE)
(2022)
Proceedings Paper
Green & Sustainable Science & Technology
Sebastian Neira, Zoe Blatsi, Paul Judge, Michael Merlin, Javier Pereda
Summary: This paper investigates the addition of an extra branch with Energy Storage units to the Modular Multilevel Converter topology, providing energy buffering and power exchange capabilities without impacting the existing configuration.
2021 IEEE 12TH ENERGY CONVERSION CONGRESS AND EXPOSITION - ASIA (ECCE ASIA)
(2021)
Proceedings Paper
Green & Sustainable Science & Technology
Paul D. Judge, Ross Mathieson, Stephen Finney
Summary: A new high-bandwidth multilevel gate-drive topology for Silicon Carbide Active Gate-Driver Development is presented in this paper. It is able to effectively drive high-power SiC MOSFETS and is easily reproducible. Experimental results confirm MMGD's active influence on the switching behavior of high-power devices.
2021 IEEE 12TH ENERGY CONVERSION CONGRESS AND EXPOSITION - ASIA (ECCE ASIA)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Zoe Blatsi, Sebastian Neira, Paul D. Judge, Michael M. C. Merlin, Stephen J. Finney
Summary: This paper discusses a modified MAW topology with integrated partially-rated Energy Storage Cascaded H-Bridge branches in parallel with a portion of the MMC stacks, enabling power flow between the ES branches and the ac or dc sides. The focus is on the design of controllers and balancing algorithms needed to achieve energy balancing between split substacks.
2021 IEEE 22ND WORKSHOP ON CONTROL AND MODELLING OF POWER ELECTRONICS (COMPEL)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Zehong Liao, Paul Judge, Michael Merlin, Stephen Finney
Summary: The paper proposes a method for improving the output voltage resolution of the stacked multicell converter (SMC) by modifying the capacitor voltage ratios to increase the switching voltage level. Through the study, it is found that with reduced computational burden, the performance of a SMC constructed with three stacked subcells can be explored under different operation modes.
2021 IEEE 22ND WORKSHOP ON CONTROL AND MODELLING OF POWER ELECTRONICS (COMPEL)
(2021)
Review
Computer Science, Information Systems
Theodor Heath, Mike Barnes, Paul D. Judge, Geraint Chaffey, Phil Clemow, Tim C. Green, Peter R. Green, James Wylie, Georgios Konstantinou, Salvador Ceballos, Josep Pou, Mohamed Moez Belhaouane, Haibo Zhang, Xavier Guillaud, Jack Andrews
Summary: This study discusses the increasing importance of cascaded multilevel converters and modular multilevel converters in power systems, as well as design considerations and lessons learned in constructing laboratory-scale prototype CMCs.
Proceedings Paper
Engineering, Electrical & Electronic
Zehong Liao, Paul D. Judge, Michael M. C. Merlin, Stephen J. Finney
2020 IEEE 9TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (IPEMC2020-ECCE ASIA)
(2020)
Proceedings Paper
Automation & Control Systems
Marlee Basurto, Paul Judge, Michael Merlin, Stephen Finney
2020 IEEE 21ST WORKSHOP ON CONTROL AND MODELING FOR POWER ELECTRONICS (COMPEL)
(2020)
