具备直流故障清除和自均压能力的MMC移位全桥子模块拓扑  

Topology of MMC Oblique-connection Full-bridge Sub-module with Capability of DC Fault Clearing and Voltage Self-balancing

作　　者：王琛[1] 谭开东 王毅[1,2] 郭汉臣 陶建业 WANG Chen;TAN Kaidong;WANG Yi;GUO Hanchen;TAO Jianye(Key Laboratory of Distributed Energy Storage and Micro-grid of Hebei Province(North China Electric Power University),Baoding 071003,China;State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Baoding 071003,China)

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

出　　处：《电力系统自动化》2020年第24期151-160,共10页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(2018YFB0904104)

摘　　要：模块化多电平换流器(MMC)可通过改进子模块拓扑实现对直流故障电流的清除,但大多数子模块不具备电容电压自均衡能力。在全桥子模块的基础上,推导了一种兼具故障电流自清除能力和模块电容电压自均衡能力的新型子模块:移位全桥子模块(OCFBSM)。该子模块由2个全桥子模块通过移位组合构成,正常工作时根据2个电容的连接关系运行在旁路、串联和并联3种状态,可不依赖于外加均压控制自动实现模块内电容电压均衡。发生直流短路故障时,OCFBSM通过将2个电容反向接入故障回路可自动清除直流故障电流。基于MATLAB/Simulink的仿真结果验证了OCFBSM在直流故障电流清除和自均压方面的有效性,且故障闭锁后各子模块电容电压均衡,有利于MMC重启。Modular multilevel converter(MMC)can realize DC fault current clearing by improving the sub-module topology,but most sub-modules do not have the capacitor voltage self-balancing capability.Based on the full-bridge sub-module,a novel submodule named oblique-connection full-bridge sub-module(OCFBSM)with fault current self-clearing capability and module capacitor voltage self-balancing capability is derived.The OCFBSM is composed of two full-bridge sub-modules by shifting combination.Under normal working conditions,it can operate in bypass,series and parallel states according to the connection relationship of two capacitors,which leads to the voltage balance of module capacitors without additional voltage balancing control.In the case of DC short-circuit fault,the OCFBSM can automatically clear the DC fault current by reversely putting two capacitors into the fault circuit.The effectiveness of the OCFBSM in DC fault current clearing and voltage self-balancing is verified by simulation results based on MATLAB/Simulink.Moreover,capacitor voltages are balanced after the fault blocking of submodules,which is conducive to the restart of MMC.

关 键 词：模块化多电平换流器 子模块拓扑 直流故障电流清除 自均压 移位组合 

分 类 号：TM721.1[电气工程—电力系统及自动化]