MMC-HVDC内部谐波模态识别及其稳定性分析  

Identification and Stability Analysis of the Internal Harmonic Modes of the MMC-HVDC System

作　　者：李探[1] 赵成勇 Aniruddha M.Gole 

机构地区：[1]国网北京经济技术研究院,北京市昌平区102209 [2]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206 [3]曼尼托巴大学

出　　处：《中国电机工程学报》2017年第8期2185-2195,共11页Proceedings of the CSEE

摘　　要：基于"动态相量"的思想建立对不同环流抑制策略下的模块化多电平换流器(modular multilevel converter,MMC)小信号模型,并通过与时域仿真的对比验证所建小信号模型的精确性。然后对小信号模型进行模态分析,通过计算参与因子将MMC-HVDC系统的模态分为"外部模态"和"内部谐波模态",并表明采用简化MMC端模型无法对内部谐波模态进行分析。另外,对MMC内部谐波模态及其影响因素进行重点详细的分析,分析表明,MMC的内部谐波模态通常呈弱阻尼特性,在系统稳定性分析中不能忽略,换流器的环流抑制策略、等效桥臂电阻、外部主控制器增益等都对内部谐波模态具有较大影响,并揭示MMC的"内部谐波不稳定"现象。最后揭示各因素对MMC内部谐波模态稳定性的影响规律,对工程参数设计和调试具有现实的指导意义。The small-signal model of the modular multilevel converter （MMC） with various of circulating current suppressing strategies was established, based on the concept of ＂dynamic phasor＂. The small-signal model was validated by comparison with the time-domain simulation. Then mode analysis was implemented and the participation factors of the Variables in the modes were calculated, based on which the modes of the MMC-HVDC system are divided into ＂external modes＂ and ＂internal harmonic modes＂. It is demonstrated that a simplified small-signal model which neglects the internal harmonic dynamics can not be used to analyze the ＂internal harmonic modes,. Then, the internal harmonic modes were analyzed and the factors influencing these modes were researched in detail. It is revealed that the internal harmonic modes are always poorly damped, and can not be neglected when doing stability analysis. The circulating current suppressing strategy, the equivalent arm resistance; the outer loop controller parameters all have great influence on these modes. The ＂internal harmonic instability＂ phenomenon was revealed for the first time. At last, some conclusions on how the internal harmonic modes are influenced were derived, which are of significance for controller parameters design and project debugging.

关 键 词：模块化多电平换流器 小信号稳定性 内部谐波模态 内部谐波不稳定 

分 类 号：TM712[电气工程—电力系统及自动化]