新跨接双极三电平子模块拓扑及其控制策略  

New crossing bipolar three-level sub-module topology and its control strategy

作　　者：张建坡[1] 闫语 田新成[2] ZHANG Jianpo;YAN Yu;TIAN Xincheng(School of Electrical and Electronic Engineering,North China Electric Power University,Baoding 071003,China;State Grid Tangshan Power Corporation,Tangshan 063000,China)

机构地区：[1]华北电力大学电气与电子工程学院,河北保定071003 [2]国网唐山供电公司,河北唐山063000

出　　处：《电力自动化设备》2022年第4期114-120,共7页Electric Power Automation Equipment

基　　金：河北省自然科学基金资助项目(E2019502123)。

摘　　要：基于半桥型子模块拓扑的模块化多电平换流器不具备直流短路故障电流阻断能力,影响了低成本架空线的应用。为抑制直流故障时的短路电流,研究了一种新跨接单极三电平子模块拓扑,解决了混合拓扑中电容不均衡充电问题。然后为应对子模块闭锁对换流站和电网可能产生的不利影响,设计了一种新跨接正、负极三电平子模块拓扑,并分析了其过调制运行、降直流电压运行和桥臂电流方向变化工况时所提拓扑的正、负电平输出要求,进一步减少了子模块中功率器件数量并研究了其控制策略。最后在PSCAD/EMTDC中搭建仿真模型,对所提新跨接双极三电平子模块拓扑过调制运行、自均压特性及闭锁抑制特性进行了仿真验证。仿真结果表明,所设计的拓扑及控制策略能够有效抑制直流故障时的短路电流。The modular multilevel converter based on the half-bridge sub-module topology does not have the ability of DC short circuit fault blocking,which affects the application of low-cost overhead lines.In order to suppress the short circuit current during DC fault,a new crossing unipolar three-level sub-module topology is studied to solve the unbalanced charging problem of capacitors in hybrid topology.Then in order to cope with the possible adverse effects of sub-module blocking on the converter and the power grid,a new crossing positive-pole and negative-pole three-level sub-module topology is designed,and the output requirements of positive level and negative level are analyzed under the operation conditions of over-modulated operation,DC voltage decrement operation and arm bridge current direction variation.The number of power devices in the sub-modules is further reduced and their control strategies are studied.Finally,the simulation model is built in PSCAD/EMTDC to verify the over-modulated operation,voltage self-balancing characteristics and blocking suppression characteristics of the proposed new crossing bipolar three-level sub-module topology.The simulative results show that the designed topology and control strategy can effectively suppress the short circuit current during DC fault.

关 键 词：模块化多电平换流器 直流故障 短路电流 新跨接双极三电平子模块 自均压特性 

分 类 号：TM46[电气工程—电器]