摘要
模块化多电平换流器高压直流输电(MMC-HVDC)系统的控制策略及电流内环控制器对其故障时的运行特性有着重要影响。设计了电网电压不平衡下负序电流抑制策略和对应的限流环节。为解决正负双序同步旋转坐标下电流序分量分解和控制器较多问题,构建了基于比例积分和谐振控制的混合电流矢量控制。此外为降低桥臂环流对系统运行的影响,在分析桥臂电流构成成分的基础上,针对环流序分量2倍频特点设计了桥臂环流抑制器。仿真结果表明混合电流矢量控制能够实现直流和2倍频交流电流信号的统一控制,达到了负序电流和桥臂环流的抑制效果。
The control strategy and the inner-loop current controller of MMC-HVDC（Modular Multilevel Converter based High Voltage Direct Current） transmission system affect greatly its operating performance during a fault. The negative-sequence current suppression strategy in the condition of unbalanced grid voltage and corresponding over-current limiter are designed. A HCVC（Hybrid Current Vector Controller） based on PI and resonance control is constructed to solve the complex problem of current sequence extraction and control in the dq reference frame of positive and negative sequences. Based on the analysis of leg current components and in order to reduce the impact of leg circulating current on system operation,a leg circulating current suppressor is designed according to its feature of double base frequency. The simulative results show that the introduced HCVC control DC and double base frequency AC uniformly,effectively suppressing the negative-sequence current and circulating current.
出处
《电力自动化设备》
EI
CSCD
北大核心
2015年第11期103-108,共6页
Electric Power Automation Equipment
关键词
模块化多电平换流器
高压直流输电
混合电流矢量控制
桥臂环流
modular multilevel converter
HVDC power transmission
hybrid current vector control
leg circulating current
