一种新型MMC并联双端口子模块及其三阶段故障电流阻断机理  

A novel MMC parallel dual-port submodule and its three-stage fault current blocking mechanism

作　　者：王琛[1,2] 魏子文 王毅[1,2] 张振[1] 江仁斌 WANG Chen;WEI Ziwen;WANG Yi;ZHANG Zhen;JIANG Renbin(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Baoding 071003,China;Hebei Key Laboratory of Distributed Energy Storage and Micro-Grid(North China Electric Power University),Baoding 071003,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),河北保定071003 [2]河北省分布式储能与微网重点实验室(华北电力大学),河北保定071003

出　　处：《电力系统保护与控制》2023年第1期81-92,共12页Power System Protection and Control

基　　金：国家自然科学基金项目资助(52077079);河北省自然科学基金项目资助(E2021502048)。

摘　　要：为使模块化多电平换流器(modular multilevel converter,MMC)具备直流故障自清除能力和电容电压均衡能力,提出了一种新型并联双端口子模块:钳位双全桥子模块(clamp double full bridge submodule,CD-FBSM)。该子模块器件成本和运行损耗较低,正常工作时相邻子模块之间具有多种协同运行模式,通过特有的并联模式可提高电容电压均衡度。故障闭锁时,模块内部电容并联、模块之间电容串联且反向接入电路,能够可靠阻断故障电流并均衡电容电压,有利于系统快速重启。此外,提出了三阶段故障电流阻断机理分析方法,对CD-FBSM的故障电流阻断过程进行了研究。通过Matlab/Simulink的仿真结果表明,所提子模块电容电压均衡度较高,可快速阻断故障电流,且故障电流阻断过程与理论分析一致。To equip a modular multilevel converter(MMC)with DC fault self-clearing and capacitor voltage balancing capability,a novel parallel dual-port submodule named clamp double full bridge submodule(CD-FBSM)is proposed.Both device cost and operating loss of CD-FBSM are low,and during a normal working state,there are multiple coordinated operation modes between adjacent submodules,and the balance degree of the capacitor voltage can be enhanced by the unique parallel mode.When CD-FBSMs are blocked because of a fault,capacitors inside submodules are parallel while capacitors between submodules are serial,and all capacitors are reversely connected into a circuit.The fault current can be reliably blocked and the voltage of capacitors is balanced.This is conducive to a quick system restart.In addition,a three-stage analyzing method for the fault current blocking mechanism is proposed,and the fault current blocking procedure of CD-FBSM is researched.Simulation results based on Matlab/Simulink show that the proposed submodule has high balance degree of capacitor voltage,and the fault current can be quickly blocked while the blocking procedure is consistent with the theoretical analysis.

关 键 词：模块化多电平换流器 子模块拓扑 直流故障 电容电压均衡 故障电流阻断机理 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM46