桥臂复用MMC单极接地故障无闭锁穿越及能量均衡

doi:10.19595/j.cnki.1000-6753.tces.232010

摘要
图/表
参考文献
相关文章 (5)

全文: PDF (21104 KB)
输出: BibTeX | EndNote (RIS)

摘要

考虑到模块化多电平换流器（MMC）的轻型化和发生概率最高的单极接地故障穿越要求,桥臂复用模块化多电平换流器（AM-MMC）在单极接地故障下的无闭锁穿越及能量均衡问题亟待解决。本文在AM-MMC拓扑结构及工作原理的基础上分析了AM-MMC的单极接地故障特性,推导了故障电流数学表达式。通过在上、下臂配置全桥子模块,混合AM-MMC (HAM-MMC)可具备无闭锁单极接地故障穿越能力并减少25%的电容数量,在轻型化及经济成本方面具有一定的竞争力。由于AM-MMC复杂的复用模式及单极接地故障导致的上、下臂不对称,本文重点分析了其穿越过程中的能量不均衡机理,提出了通过基频及二倍频直接环流控制均衡桥臂能量的交替复用无闭锁单极接地故障穿越策略。基于Matlab/Simulink的仿真结果表明,HAM-MMC可无闭锁穿越单极接地故障,且所提控制策略较常规MMC均衡能量效果更好。

	服务

	把本文推荐给朋友
	加入我的书架
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章
	李宇薇
	王毅
	高玉华
	于义轩
	王琛

关键词 ：模块化多电平换流器（MMC）, 桥臂复用, 单极接地故障, 无闭锁穿越, 能量均衡

Abstract：

The numerous submodules and floating capacitors in the modular multilevel converter (MMC) result in tremendous weight and high cost. In addition, the existing MMC projects based on half-bridge submodules (HBSMs) cannot deal with DC faults and requires submodules with more devices, which further increases weight and volume. Recently, an arm-multiplexing modular multilevel converter (AM-MMC) was proposed, which had similar operation performance to the conventional MMC with 25% less capacitors. However, its complex structure and multiplexing mode pose problems to pole-to-ground fault riding-through and energy balance. To address these issues, this article deeply analyzes its fault characteristics and energy balance mechanism, and proposes the submodule configuration and non-blocking pole-to-ground fault ride-through strategy. By configuring full-bridge submodules (FBSMs) in the upper and lower arms and implementing fundamental and second harmonic direct circulating current control, the hybrid AM-MMC (HAM-MMC) can use the negative level output capability to reduce the DC voltage bias of the faulty pole and ride through faults.
Firstly, after detecting the pole-to-ground fault, FBSMs in the faulty pole arm should output negative levels to reduce the arm voltage by 50% DC voltage and arm switches alternate according to the switching threshold of the healthy pole. Calculated fundamental and second harmonic currents need injecting to achieve the converter energy balance. Secondly, the charging and discharging status of FBSMs changes when output negative levels, and the submodule capacitor voltage balance sorting scheme should be adjusted. Thirdly, the reference DC voltage should be reduced to half for converters controlled by fixed DC voltage, and the reference power be half for the fixed active power converters. Finally, after the fault is cleared, normal modulation and power transmission are restored, and the fault is successfully ride through. This way, the strategy solves the energy imbalance problem between arms and submodules in AM-MMC caused by asymmetric faults.
Simulation results on the pole-to-ground fault riding-through of HAM-MMC show that, when only alternating arm switches without circulating current control, the submodule capacitor voltage, arm current, and DC current fluctuate due to the arm energy imbalance. The system is unstable, and arm switches exceed the withstand voltage and current capacity. After adding the fundamental and second harmonic circulating current control, the arm switches operate within the normal range. The middle arm submodules participate in capacitor voltage sorting throughout the entire process. Both the DC current and submodule capacitor voltage remain stable, still able to transmit 50% active power. After the fault cleared, the system can quickly restore, which verifies the effectiveness of the fundamental and second harmonic direct circulating current control.
The following conclusions can be drawn from the simulation analysis: (1) Compared with traditional HF-MMC, HAM-MMC requires the same number of IGBTs but reduces the number of capacitors by 25%, which still has significant advantages in terms of lightweight and cost. (2) By configuring FBSMs in the upper and lower arms and implementing fundamental and second harmonic direct circulating current control, HAM-MMC can output negative levels to reduce the DC voltage bias of the faulty pole to 0, riding through pole-to-ground faults without blocking and maintaining 50% power transmission. (3) During the HAM-MMC alternating multiplexing riding-through, submodules in the middle arm participate in the capacitor voltage sorting and transfer energy throughout the entire process. The voltages of the submodule capacitors in the three arms are basically equal, resulting in a better energy balance effect. Compared with conventional MMC, it can ride through faults and recover faster.

Key words： Modular multilevel converter (MMC) arm-multiplexing pole-to-ground fault non-blocking ride-through energy balance

收稿日期: 2023-12-04

PACS:

TM721.1

基金资助:

国家自然科学基金（资助项目52077079）

通讯作者: 王毅男,1977年生,教授,博士生导师,研究方向为新能源与储能构网控制、柔性直流输配电网拓扑与控制。E-mail：yi.wang@ncepu.edu.cn

作者简介: 李宇薇女,1991年生,博士研究生,研究方向为柔性直流输电。E-mail：liyuwei@ncepu.edu.cn

引用本文:

李宇薇, 王毅, 高玉华, 于义轩, 王琛. 桥臂复用MMC单极接地故障无闭锁穿越及能量均衡[J]. 电工技术学报, 0, (): 9-. Li Yuwei, Wang Yi, Gao Yuhua, Yu Yixuan, Wang Chen. Pole-to-Ground Fault Riding-through and Energy Balance of Arm-Multiplexing MMC. Transactions of China Electrotechnical Society, 0, (): 9-.

链接本文:

https://dgjsxb.ces-transaction.com/CN/10.19595/j.cnki.1000-6753.tces.232010 https://dgjsxb.ces-transaction.com/CN/Y0/V/I/9

[1] Ghat M B, Patro S K, Shukla A.The hybrid-legs bridge converter: a flexible and compact VSC-HVDC topology[J]. IEEE Transactions on Power Electronics, 2021, 36(3): 2808-2822.
[2] 茆美琴, 程德健, 袁敏, 等. 基于暂态能量流的模块化多电平高压直流电网接地优化配置[J]. 电工技术学报, 2022, 37(3): 739-749.
Mao Meiqin, Cheng Dejian, Yuan Min, et al.Optimal allocation of grounding system in high voltage direct current grid with modular multi-level converters based on transient energy flow[J]. Transactions of China Electrotechnical Society, 2022, 37(3): 739-749.
[3] 武鸿, 王跃, 刘熠, 等. 基于广义电容电压不平衡度的MMC子模块开路故障诊断策略[J]. 电工技术学报, 2023, 38(14): 3909-3922.
Wu Hong, Wang Yue, Liu Yi, et al.Open circuit fault diagnosis strategy of MMC sub-module based on generalized capacitor voltage unbalance[J]. Transactions of China Electrotechnical Society, 2023, 38(14): 3909-3922.
[4] Zhao Cong, Hu Yujie, Luan Kedong, et al.Energy storage requirements optimization of full-bridge MMC with third-order harmonic voltage injection[J]. IEEE Transactions on Power Electronics, 2019, 34(12): 11661-11678.
[5] 樊强, 俞永杰, 夏嘉航, 等. 低容值半桥型模块化多电平变换器直流故障辅助清除策略[J]. 电工技术学报, 2022, 37(14): 3713-3722.
Fan Qiang, Yu Yongjie, Xia Jiahang, et al.Auxiliary strategy for DC fault clearing of low capacitance half-bridge modular multilevel converter[J]. Transactions of China Electrotechnical Society, 2022, 37(14): 3713-3722.
[6] 高玉华, 王琛, 王毅, 等. 基于半波交替的轻型化MMC拓扑及控制策略[J]. 电力系统自动化, 2023, 47(17): 149-159.
Gao Yuhua, Wang Chen, Wang Yi, et al.Topology and control strategy of light-weight modular multilevel converter with half-wave alternating[J]. Automation of Electric Power Systems, 2023, 47(17): 149-159.
[7] 楚天全媒体. 自主创新打破技术壁垒中国海上风电事业稳步迈向未来 [EB/OL].[2020-12-08]. https://baijiahao.baidu.com/s?id=1685492049038188254&wfr=spider&for=pc.
[8] 周海鸿, 杨明发, 阮俊峰. MMC-HVDC输电系统直流故障隔离综述[J]. 电气技术, 2019, 20(1): 1-6.
Zhou Haihong, Yang Mingfa, Ruan Junfeng.Summarization of DC fault isolation in MMC-HVDC transmission system[J]. Electrical Engineering, 2019, 20(1): 1-6.
[9] Tang Yuan, Chen Minjie, Ran Li.A compact MMC submodule structure with reduced capacitor size using the stacked switched capacitor architecture[J]. IEEE Transactions on Power Electronics, 2016, 31(10): 6920-6936.
[10] Han Xiao, Chen Yuxin, Li Rui, et al.An optimization method for minimizing the submodule capacitance of modular multilevel converter[C]//2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC), Shenzhen, China, 2018: 1-6.
[11] Debnath S, Qin Jiangchao, Saeedifard M.Control and stability analysis of modular multilevel converter under low-frequency operation[J]. IEEE Transactions on Industrial Electronics, 2015, 62(9): 5329-5339.
[12] 王琛, 陶建业, 王毅, 等. 桥臂复用型模块化多电平换流器的拓扑及控制研究[J]. 中国电机工程学报, 2022, 42(9): 3373-3385.
Wang Chen, Tao Jianye, Wang Yi, et al.Research on topology and control of arm multiplexing modular multilevel converter[J]. Proceedings of the CSEE, 2022, 42(9): 3373-3385.
[13] 王琛, 陶建业, 王毅, 等. 半桥-全桥子模块混合型桥臂复用MMC的拓扑及故障穿越策略研究[J]. 中国电机工程学报, 2022, 42(22): 8297-8309.
Wang Chen, Tao Jianye, Wang Yi, et al.Research on topology and fault ride-through strategy of hybrid arm multiplexing MMC composed of HBSMs and FBSMs[J]. Proceedings of the CSEE, 2022, 42(22): 8297-8309.
[14] Wang Yi, Li Yuwei, Wang Chen, et al.A lightweight hybrid modular multilevel converter topology for DC fault blocking[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2023, 11(5): 4945-4955.
[15] Wang Yi, Li Yuwei, Wang Chen, et al.A hybrid arm-multiplexing MMC for DC fault ride-through without blocking[J]. IET Renewable Power Generation, 2023, 17(9): 2225-2235.
[16] 樊强, 赵成勇, 许建中. 桥臂复用型MMC拓扑启动及降容策略研究[J]. 中国电机工程学报, 2022, 42(19): 7150-7160.
Fan Qiang, Zhao Chengyong, Xu Jianzhong.Research on startup and capacitance reduction strategy of bridge arm reusing MMC topology[J]. Proceedings of the CSEE, 2022, 42(19): 7150-7160.
[17] Zhang Zheren, Xu Zheng.Short-circuit current calculation and performance requirement of HVDC breakers for MMC-MTDC systems[J]. IEEJ Transactions on Electrical and Electronic Engineering, 2016, 11(2): 168-177.
[18] 蔡洋, 郭文勇, 赵闯, 等. 模块化多电平换流器直流故障过电流精确计算与分析[J]. 电工技术学报, 2021, 36(7): 1526-1536.
Cai Yang, Guo Wenyong, Zhao Chuang, et al.The accurate calculation and analysis of overcurrent under modular multilevel converter DC fault[J]. Transactions of China Electrotechnical Society, 2021, 36(7): 1526-1536.
[19] 罗永捷, 徐罗那, 熊小伏, 等. MMC-MTDC系统直流单极对地短路故障保护策略[J]. 电工技术学报, 2017, 32(增刊1): 98-106.
Luo Yongjie, Xu Luona, Xiong Xiaofu, et al.Protection strategy of DC unipolar short circuit to ground fault in MMC-MTDC system[J]. Transactions of China Electrotechnical Society, 2017, 32(S1): 98-106.
[20] Ray A, Rajashekara K, Banavath S N, et al.Coupled inductor-based zero current switching hybrid DC circuit breaker topologies[J]. IEEE Transactions on Industry Applications, 2019, 55(5): 5360-5370.
[21] Marquardt R.Modular Multilevel Converter: an universal concept for HVDC-Networks and extended DC-Bus-applications[C]//The 2010 International Power Electronics Conference - ECCE ASIA -, Sapporo, Japan, 2010: 502-507.
[22] 赵鹏豪, 王朝亮, 许建中, 等. 一种具有直流故障穿越能力的MMC子模块拓扑[J]. 电网技术, 2014, 38(12): 3441-3446.
Zhao Penghao, Wang Chaoliang, Xu Jianzhong, et al.A sub-module topology of MMC with DC fault ride-through capability[J]. Power System Technology, 2014, 38(12): 3441-3446.
[23] Xiang Wang, Lin Weixing, An Ting, et al.Equivalent electromagnetic transient simulation model and fast recovery control of overhead VSC-HVDC based on SB-MMC[J]. IEEE Transactions on Power Delivery, 2017, 32(2): 778-788.
[24] Chen Chao, Adam G P, Finney S, et al.H-bridge modular multi-level converter: control strategy for improved DC fault ride-through capability without converter blocking[J]. IET Power Electronics, 2015, 8(10): 1996-2008.
[25] Cui Shenghui, Sul S K.A comprehensive DC short-circuit fault ride through strategy of hybrid modular multilevel converters (MMCs) for overhead line transmission[J]. IEEE Transactions on Power Electronics, 2016, 31(11): 7780-7796.
[26] 孔明, 汤广福, 贺之渊. 子模块混合型MMC-HVDC直流故障穿越控制策略[J]. 中国电机工程学报, 2014, 34(30): 5343-5351.
Kong Ming, Tang Guangfu, He Zhiyuan.A DC fault ride-through strategy for cell-hybrid modular multilevel converter based HVDC transmission systems[J]. Proceedings of the CSEE, 2014, 34(30): 5343-5351.
[27] 路茂增. 混合型模块化多电平换流器能量均衡机理分析与控制研究[D]. 武汉: 华中科技大学, 2018.
[28] Junyent-Ferré A, Clemow P, Merlin M M C, et al. Operation of HVDC Modular Multilevel Converters under DC pole imbalances[C]//2014 16th European Conference on Power Electronics and Applications, Lappeenranta, Finland, 2014: 1-10.
[29] Hu Jiabing, Xu Kecheng, Lin Lei, et al.Analysis and enhanced control of hybrid-MMC-based HVDC systems during asymmetrical DC voltage faults[J]. IEEE Transactions on Power Delivery, 2017, 32(3): 1394-1403.
[30] Xiang Wang, Lin Weixing, Xu Lie, et al.Enhanced independent pole control of hybrid MMC-HVdc system[J]. IEEE Transactions on Power Delivery, 2018, 33(2): 861-872.
[31] 潘子迅,杨晓峰,赵锐,等.不平衡电网下模块化多电平换流器的直流环流均衡策略[J/OL].电工技术学报:1-11[2023-2-24]. https://doi.org/10.19595/j.cnki.1000-6753.tces.222180.
Pan Zixun, Yang Xiaofeng, Zhao Rui, et al. DC circulating current balancing control of modular multilevel converter under unbalanced power grid [J/OL]. Transactions of China Electrotechnical Society: 1-11[2023-2-24]. https://doi.org/10.19595/j. cnki.1000-6753.tces.222180.
[32] 陈晴, 薛源, 王克, 等. 用于海上风电并网的柔性直流系统过电压和绝缘配合研究[J]. 高压电器, 2019, 55(4): 178-184.
Chen Qing, Xue Yuan, Wang Ke, et al.Research on overvoltage and insulation coordination of flexible DC system for offshore wind farm integration[J]. High Voltage Apparatus, 2019, 55(4): 178-184.