Article
Engineering, Electrical & Electronic
Qingsong Wang, Zhouliang Hong, Fujin Deng, Ming Cheng, Giuseppe Buja
Summary: In this article, a novel diagnosis strategy is proposed for open-circuit faults (OCFs) and short-circuit faults (SCF) in modular multilevel converter topology. The OCF diagnosis strategy analyzes the current flow path and output voltage expression of each open-circuit submodule, while the SCF diagnosis strategy utilizes carrier phase-shift modulation and redundant submodules to diagnose faults and improve system security. The feasibility of the proposed diagnosis strategy is validated through simulations and experiments.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Automation & Control Systems
Cheng Wang, Hongkang Yang, Hongting Hua, Yaosuo Xue
Summary: This article presents a DTMMC-UPS with series configurations on both input/output ac sides, which provides high-voltage grid/load accessing interfaces. The use of copies of T-type legs in the system leads to common semiconductor failure, while the coupling between rectifier and inverter conversions and the confliction between intercell and inner-cell voltage balancing make fault-tolerant control challenging. The article clarifies and diagnoses switch fault types and proposes an improved voltage vector modulation to achieve normal operation on the rectifier and inverter sides.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Jingyang Fang, Shunfeng Yang, Haiyu Wang, Nima Tashakor, Stefan M. Goetz
Summary: Modular multilevel converters (MMCs) have the advantages of modularity and scalability, but face challenges such as bulky DC capacitors and voltage balance issues. This article proposes a hardware-based strategy to reduce capacitance and balance capacitor voltages effectively, leading to simplified control efforts. Experimental results validate the effectiveness of this strategy in improving MMC performance.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Ashkan Raki, Yousef Neyshabouri, Mahdi Aslanian, Hossein Iman-Eini
Summary: This article proposes a strategy consisting of two methods to tackle the problems caused by CMV injection in the postfault operation of cascaded H-bridge inverters. The strategy includes determining three regions and obtaining a safe operating area. The first method avoids power flow back, while the second method shifts FCMV into the safe operating area to prevent overload operation of cells.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Automation & Control Systems
Aleksandr Viatkin, Mattia Ricco, Riccardo Mandrioli, Tamas Kerekes, Remus Teodorescu, Gabriele Grandi
Summary: A new Modular Multilevel Converter with Interleaved half-bridge Sub-Modules (ISM-MMC) is proposed in this article, which exhibits higher modularity and scalability for ultrafast chargers. A hybrid modulation scheme is implemented to exploit the advantages of the interleaving scheme. Comparative study verifies the effectiveness of the proposed topology.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Automation & Control Systems
Pingyuan Lyu, Jiangming Huang, Guipeng Chen, Wenfeng Cui
Summary: This article proposes a simple fault-tolerant strategy to enhance the reliability of the asymmetric half-bridge dual-output converter. By reconstructing the topology with redundant switches, normal output voltages can still be maintained in the event of an open-circuit fault. Two reconstructed topologies are obtained in postfault modes depending on the faulty switches, and they can operate similarly using a modified modulation scheme. Additionally, a simple fault detection scheme is introduced using a voltage sensor to quickly diagnose open-circuit faults in all switches, enabling smooth mode transitions.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Energy & Fuels
Changwu Hou, Xiaofeng Zhang, Zhihao Ye, Jing Huang
Summary: This paper investigates the fault characteristics of modular multilevel converters in DC power transmission, with a focus on permanent DC bipolar short-circuited faults. By analyzing and simulating the system, the expressions of fault characteristic parameters are deduced, and the influence of main circuit parameters on characteristic variables is studied, providing a theoretical basis for current-limiting control and relay protection.
Article
Engineering, Electrical & Electronic
Mitsuyoshi Enomoto, Kenichiro Sano, Junya Kanno, Junichi Fukushima
Summary: This article introduces a multicircuit HVDC system that can localize dc line faults without using dc circuit breakers. The conventional fault clearing method can cause wind power plants to shutdown and restart, resulting in power supply suspension. This suspension may affect the balance of supply and demand, and cause frequency drop in the onshore ac power system. To solve this problem, the article proposes a system switching method that allows continuous operation of wind power plants during dc line faults. The proposed method uses a half-bridge modular multilevel converter to clear the faults while keeping the wind power plants running. This method ensures continuous operation of wind power plants and reduces transmission outage to 0.2 s, significantly improving supply reliability. Experimental results validate the effectiveness of the proposed method.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Automation & Control Systems
Aleksandr Viatkin, Mattia Ricco, Riccardo Mandrioli, Tamas Kerekes, Remus Teodorescu, Gabriele Grandi
Summary: A new state-observer-based current balancing method for ISM-MMC is proposed, which reduces imbalance by estimating currents and voltages, and a novel capacitor voltage balancing strategy is developed.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Jingyang Fang, Zhongxi Li, Stefan M. Goetz
Summary: This article proposes novel multilevel converters with symmetrical half-bridge submodules to reduce the number of active switch semiconductors and conduction losses. It also introduces a sensorless voltage balance scheme to eliminate capacitor voltage mismatch problems, greatly reducing capacitor voltage ripples and saving dc capacitances. Simulation and experimental results validate the superiority of the proposed multilevel converters and voltage balance scheme.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Govind Avinash Reddy, Anshuman Shukla
Summary: In this article, a new enhanced modular multilevel converter (EMMC) is introduced, which addresses the drawbacks of the conventional modular multilevel converters (MMC). The EMMC, based on a new submodule (SM) structure, is fully modular and requires fewer switches and capacitors. It possesses the features of reduced energy-storage requirement and dc fault-tolerant capability.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Computer Science, Information Systems
Kenichiro Sano, Hiro Nakayama
Summary: This study proposes a novel protection method for symmetrical monopole HVDC systems, which introduces lower arm short protection and upper arm short protection modes as well as inserts blocking diodes to the DC terminal of the inverter to suppress overvoltage, achieving successful power transmission in the non-faulted pole during and after a DC fault.
Article
Automation & Control Systems
Yu Jin, Qian Xiao, Hongjie Jia, Yanchao Ji, Tomislav Dragicevic, Remus Teodorescu, Frede Blaabjerg
Summary: This article proposes a simplified and fast software-based fault detection and localization approach for the grid-connected modular multilevel converter. By calculating and comparing the errors between measured and estimated state variables, switch faults can be detected and localized. A modified Pauta criterion is used to confirm the faults. Simulation and experimental results demonstrate the effectiveness of the proposed approach.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Zhi Geng, Minxiao Han, Weiqi Bao, Wenqiang Xie
Summary: This article proposes a new submodule (SM) capable of fault tolerance, integrating an operating half-bridge SM (HBSM) and a backup HBSM. The SM ensures charging the capacitor in the backup HBSM and tolerates different faults. The proposed SM simplifies the fault-tolerant method (FTM) and overcomes drawbacks of existing FTMs.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Ramin Razani, Yasser Abdel-Rady I. Mohamed
Summary: This article proposes a tailored fault-tolerant operation strategy for the dc/dc modular multilevel converter (MMC) in the case of submodules (SMs) faults. The strategy utilizes the unique characteristics of the dc/dc MMC to enable post-fault operation without redundant SMs. The effectiveness of the strategy is confirmed through simulation studies in MATLAB\Simulink environment.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Yaoqiang Wang, Juncheng Ye, Kaige Wang, Fuquan Nie, Gen Li, Jun Liang
Summary: This paper proposes a nine-level switched-capacitor step-up inverter (9LSUI) that achieves quadruple voltage gain with a single dc source. The inverter effectively reduces the voltage stress on switches by eliminating the H-bridge, keeping the peak inverse voltage within 2V(dc). It can also integrate inductive load and achieve capacitor voltage self-balancing without auxiliary circuits. The topology structure can be flexibly extended to raise output levels while maintaining constant peak inverse voltage of switches.
JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yaoqiang Wang, Juncheng Ye, Ruohan Ku, Yuchen Shen, Gen Li, Jun Liang
Summary: This article presents a modular switched-capacitor multilevel inverter that achieves triple voltage gain using two capacitors and a single dc source. The proposed topology has a lower voltage stress, can integrate inductive load, and achieves capacitor voltage self-balancing.
JOURNAL OF POWER ELECTRONICS
(2023)
Article
Engineering, Multidisciplinary
Renxin Yang, Gang Shi, Chen Zhang, Gen Li, Xu Cai
Summary: A novel grid-forming control strategy is proposed to address the instability of the DC voltage in the Modular Multilevel Converter-based High-Voltage Direct-Current (MMC-HVDC) transmission systems with offshore wind farm integration. In this strategy, grid synchronization is achieved by utilizing the intrinsic power balancing regime of the MMC's submodule capacitors, instead of emulating the swing equation as required by the virtual synchronous generator (VSG) control. Additionally, proper insertion strategies and a fault-ride-through control strategy are developed to decouple the DC-link voltage and ensure power angle stability and stability of the submodule capacitor voltage. Simulation results demonstrate the effectiveness of the proposed control strategy in providing fast inertia support and satisfactory control of DC-link voltage and fault-ride-through capability.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Jianzhong Xu, Junxin Wang, Yukun Yang, Jinan Wang, Gen Li
Summary: This paper proposes an optimal dual harmonic injection strategy for hybrid modular multilevel converters (MMCs), which can suppress the submodule capacitor voltage ripples under unbalanced grid voltage conditions, reducing the volume and cost of the converters.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Energy & Fuels
Haixin Wang, Zihao Yang, Zhe Chen, Jun Liang, Gen Li, Junyou Yang, Shiyan Hu
Summary: In this paper, a multiple adaptive model predictive controller (MAMPC) is proposed to alleviate the mechanical fatigue of the main shaft in all speed sections. The effectiveness of the method is verified through extensive simulations, showing a reduction in minimum frequency deviation and an extension in the number of fatigue cycles of the main shaft.
IEEE TRANSACTIONS ON ENERGY CONVERSION
(2023)
Article
Automation & Control Systems
Moke Feng, Chenxiang Gao, Jianzhong Xu, Chengyong Zhao, Gen Li
Summary: This article presents a high-speed and high-precision simulation method for the modular power electronic transformer (PET) to accelerate the simulation of its internal and external dynamics. By eliminating internal nodes and reducing the order of the nodal admittance matrix, combined with parallel computing, the proposed method achieves a significant simulation speedup. Simulation results in PSCAD/EMTDC demonstrate the accuracy and time efficiency of the proposed method compared to the detailed model.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Pengfei Yu, Jizhong Zhu, Jun Liang, Hongzhou Chen, Xiaofu Xiong
Summary: Power systems relying on clean energy face challenges due to uncertainties in power generation and risks of instability caused by low inertia. Insufficient reactive power support and rapid frequency drop after a fault can lead to disconnection of new energy generation units. The inclusion of battery energy storage systems (BESS) in the power ancillary service market can provide flexible regulation resources. However, further research is needed on how to incorporate BESS into the early-stage emergency backup services (AEBS) after failure.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Yanxun Guo, Zhuang Xu, Yaoqiang Wang, Xiaomei Yao, Jun Liang
Summary: This paper proposes a novel nonunit two-stage protection method to address the issue of high-resistance faults. By analyzing the propagation process of fault traveling waves and the characteristic differences of waves generated by DCCBs, the method achieves rapid identification and clearing of faults, with high tolerance for high-resistance faults.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Jianzhong Xu, Jin'an Wang, Feng Wang, Junxin Wang, Gen Li
Summary: This article proposes a charge balancing control strategy for a modular multilevel converter with supercapacitor energy storage system based on medium-voltage direct-current. The control strategy accurately controls the charging and discharging power and achieves state of charge balancing among supercapacitor packs. Simulation results show that the proposed control strategy improves dynamic response and reduces current ripples.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Moke Feng, Chenxiang Gao, Jianzhong Xu, Chengyong Zhao, Gen Li
Summary: A parallel simulation framework is proposed for electromagnetic transient (EMT) modeling of modularized solid-state transformers (MSST). The framework preserves the broadband characteristics of the original model and remarkably improves simulation efficiency through detailed modeling, decoupled modeling, and parallel design of simulation processes.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Zheng Shi, Yin Xu, Ying Wang, Jinghan He, Gen Li, Zhao Liu
Summary: To solve the frequency security problems caused by major faults on long-distance transmission lines, this work proposes an emergency frequency control strategy, utilizing available frequency response resources at the receiving end, including synchronous generators, local wind farms, battery-based energy storage systems, pumped hydro storages, etc. A system frequency response model consisting of multiple resources, including the secondary frequency drop caused by wind farms, is formulated and analyzed. The proposed strategy is then studied and simulated on a generalized model of the Huadong regional grid in eastern China.
IEEE TRANSACTIONS ON POWER SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Xiongfeng Fang, Gen Li, Cheng Wang, Lei Li
Summary: This study proposes a method to address the problems of branch overcurrent and submodule overvoltage in the hybrid modular multilevel converter by controlling the reverse-biased voltage of each arm, improving the safety of the system.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Automation & Control Systems
Qianhao Sun, Qiang Song, Jingwei Meng, Bin Cui, Gen Li, Fan Cheng, Kailun Wang
Summary: This article proposes a new Flex-LCC GFM HVdc rectifier for collecting power generated by large-scale islanded or weak-grid-supported renewable energy systems. The Flex-LCC features flexible control, reduced interharmonics, enhanced stability, and a balance between cost, footprint, weight, and current-carrying capacity.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Nuclear Science & Technology
Haixin Wang, Siyu Mu, Gen Li, Zihao Yang, Junyou Yang, Fausto Pedro Garcia Marquez, Xiran Zhou, Yiming Ma, Zhe Chen
Summary: This paper proposes an electrothermal coupled model for nuclear power plants (NPPs) to enhance their flexible adjustment capability and operation profits. The model combines the characteristics and constraints of nuclear power units and electric heat storage (EHS). It also develops an operation strategy and a cost calculation method for NPPs, which improve peak-shaving compensation and cost-sharing. Simulation results using the Hongyanhe Nuclear Power Plant model in China demonstrate the effectiveness of the proposed method, achieving increased EHS profit, enhanced peak-shaving compensation, reduced cost-sharing, and improved total profits.
NUCLEAR ENGINEERING AND DESIGN
(2023)
