MMC-HVDC电容协同预充电控制策略

发布时间：2018-06-26 06:22

本文选题：模块化多电平换流器 + 高压直流输电　；参考：《高电压技术》2014年08期

【摘要】：为预测基于模块化多电平换流器的高压直流输电系统(MMC-HVDC)电容预充电的准确时间并实现子模块电容的额定充电,考虑冗余子模块在内,提出了一种启动预充电和停机过程都适用的协同调制策略。首先,建立了模块化多电平启动预充电不可控阶段的动态数学模型,并据此修正了不可控阶段直流电压的表达式以及启动限流电阻选取的表达式。其次,分析了换流器解锁瞬间存在冲击电流的原因,调整了限流电阻的切除时间,从而较好地抑制了解锁时刻的冲击电流。再次,针对换流器子模块级联的特点,提出了一种模块协同直流电压的调制策略,该策略解决了换流站直流电压和子模块电容电压的匹配问题。最后,在MATLAB/Simulink中搭建了MMC-HVDC预充电仿真模型,对所提调制算法进行了仿真验证,结果表明,随着直流电压从Up开始升至Udc0期间逐渐将每相投入子模块数目从T(每桥臂子模块数目)下降至N(额定投入运行数),可以将子模块电容电压充电至额定值。
[Abstract]:In order to predict the accurate time of capacitor precharge and realize the rated charge of submodule capacitance in high voltage direct current transmission system (MMC-HVDC) based on modularized multilevel converter, redundant submodules are considered. In this paper, a cooperative modulation strategy is proposed, which is suitable for both start-up and shutdown processes. Firstly, the dynamic mathematical model of the uncontrollable stage of modularized multilevel start-up precharge is established, and the expression of DC voltage and the selection of starting current limiting resistance are revised accordingly. Secondly, the reason of the impulse current in the unlocking moment of the converter is analyzed, and the cutting time of the current limiting resistance is adjusted, thus the impulse current at the unlocking time is better suppressed. Thirdly, according to the characteristics of cascade of converter submodules, a modulating strategy of modulating DC voltage is proposed, which solves the matching problem between DC voltage and capacitor voltage of converter station. Finally, the MMC-HVDC pre-charging simulation model is built in MATLAB / Simulink. The simulation results show that the proposed modulation algorithm is verified by simulation. With the DC voltage rising from up to Udc0, the number of submodules per phase input is gradually reduced from T (number of submodules per arm) to N (operational rating), and the capacitance voltage of the submodule can be charged to the rated value.
【作者单位】：华东交通大学电气与电子工程学院;中国电力科学研究院;
【基金】：国家自然科学基金(51367008)~~
【分类号】：TM721.1

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