电网电压不平衡条件下模块化多电平换流器高压直流输电控制策略  

The Control Strategies of Modular Multilevel Converter-High Voltage Direct Current Transmission under Unbalanced Grid Voltage Conditions

作　　者：张建坡[1] 李耐心[2] 田新成[2] Zhang Jianpo Li Naixin Tian Xincheng(State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Baoding 071001 China State Grid Tangshan Power Corporation Tangshan 063000 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),保定071001 [2]国网唐山供电公司,唐山063000

出　　处：《电工技术学报》2016年第22期205-212,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点资助项目(51207054)

摘　　要：在电网电压发生不平衡故障时,分析了模块化多电平换流器高压直流输电(MCHVDC)功率分量特性。为实现正负序电流统一控制,引入复合控制器(比例积分+准谐振控制器)作为电流内环控制,避免了同步旋转坐标系下电流序分量分解问题。研究了抑制负序电流、有功功率波动控制策略,并利用电压降落和不均衡度指标设计了对应的低压限流环节。为降低环流造成的额外损耗,在分析环流分量故障特性基础上,设计了桥臂环流抑制器。最后在PSCAD/EMTDC仿真环境中,搭建了仿真模型,对负序电流、有功波动抑制和环流抑制策略的有效性进行了仿真说明。Under unbalanced grid conditions, the power characteristics of high voltage directcurrent transmission based on modular multilevel converter （MMC-HVDC） are analyzed. In order tocontrol the positive and negative sequence currents uniformly, a composite controller combingproportional integer with quasi resonant current controller is introduced as the synchronous rotationalreference frame. Thus, the current sequences extraction can be avoided. The control strategies foreliminating the negative sequence current and active power ripples are studied, and the voltagedependent current order limiter （VDCOL） is also designed according to the voltage drop and imbalanceindicator. Features of leg circulating current are analyzed, and accordingly the circulating currentsuppressor is designed to reduce the additional power loss. At last, the simulation model is built inPSCAD/EMTDC. The effectiveness and feasibility of these proposed control strategies are verified.

关 键 词：模块化多电平换流器 高压直流输电 复合控制器 控制策略 低压限流 环流 

分 类 号：TM721.1[电气工程—电力系统及自动化]