子模块混合型MMC-HVDC直流故障穿越控制策略

发布时间：2018-05-11 00:32

本文选题：模块化多电平换流器 + 高压直流输电　；参考：《中国电机工程学报》2014年30期

【摘要】：半桥和全桥子模块混合型模块化多电平换流器在具备直流故障穿越能力的同时降低了开关器件的数量。介绍其拓扑结构以及子模块数量的确定方法。阐述半桥和全桥子模块阀段自身平机理和调制电压基本分配原则,并结合最近电平逼近调制提出一种半桥和全桥阀段间平衡的控制策略。分析直流故障期间换流器的等效电路,为了减少暂态期间直流故障电流对子模块电容电压平衡的影响,提出一种基于虚拟电阻的优化控制策略。整个故障穿越期间无需闭锁换流器,且还能持续保证交流系统对无功功率的需求。基于PSCAD/EMTDC,搭建两端子模块混合型模块化多电平换流器HVDC仿真模型,针对双极直流短路工况进行仿真分析,验证了所提出的控制策略的有效性。
[Abstract]:The hybrid modularized multilevel converter with half-bridge and full-bridge submodules has the ability of DC fault crossing and reduces the number of switch devices at the same time. The topological structure and the method of determining the number of sub-modules are introduced. The self-leveling mechanism and modulation voltage distribution principle of half-bridge and full-bridge sub-module valve segments are described, and a control strategy of balance between half-bridge and full-bridge valve segments is proposed in combination with nearest level approaching modulation. The equivalent circuit of converter during DC fault is analyzed. In order to reduce the influence of DC fault current on capacitor voltage balance of submodule during transient, an optimal control strategy based on virtual resistance is proposed. There is no need to lock the converter during the whole fault traversing period, and the reactive power requirement of AC system can be ensured continuously. Based on PSCAD / EMT DC, the HVDC simulation model of hybrid modular multilevel converter with two sub-modules is built, and the simulation analysis of bipolar DC short circuit condition is carried out, which verifies the effectiveness of the proposed control strategy.
【作者单位】：国网智能电网研究院;
【基金】：国家自然科学基金项目(51177154,512111038)~~
【分类号】：TM46

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