一种模块化多电平的改进最近电平调制策略

发布时间：2018-04-23 12:00

本文选题：模块化多电平换流器 + 最近电平调制　；参考：《科学技术与工程》2017年30期

【摘要】：模块化多电平换流器(modular multilevel converter,MMC)因其模块化设计易于扩展、开关频率低等特点,在中高压大功率系统中得到越来越多的应用;而最近电平调制(nearest level modulation,NLM)作为一种实时阶梯波调制方式,常用于上百个电平数的场合。首先对MMC的基本结构和最近电平调制的运行机理进行分析,推导出该调制策略所存在的固有缺陷;在此基础上,提出了改进的最近电平调制策略。通过引入调制波与阶梯波间偏差,有效避免了在电平数较低情况下电容电压波动、环流等问题。最后在PSCAD/EMTDC中搭建了MMC仿真模型,对改进前后的最近电平调制策略进行了比较分析。仿真结果表明该改进调制策略可以提高系统的稳态运行特性,对子模块电容电压波动和环流产生抑制作用。
[Abstract]:Modularized multilevel multilevel converter (MMC) is widely used in medium-high voltage and high-power systems because of its easy to expand modularization design and low switching frequency, while the nearest level modulation level modulationNLMCs are used as a real-time step wave modulation method. Often used in the hundreds of levels of occasions. Firstly, the basic structure of MMC and the operating mechanism of the nearest level modulation are analyzed, and the inherent defects of the modulation strategy are deduced, and an improved nearest level modulation strategy is proposed. By introducing the deviation between modulation wave and step wave, the problems such as capacitance voltage fluctuation and circulation are avoided effectively when the level number is low. Finally, the MMC simulation model is built in PSCAD/EMTDC, and the recent level modulation strategy before and after the improvement is compared and analyzed. The simulation results show that the improved modulation strategy can improve the steady-state performance of the system and restrain the capacitance voltage fluctuation and circulation of the sub-module.
【作者单位】：四川大学电气信息学院;国网福建省电力有限公司电力科学研究院;
【基金】：国家电网公司科技项目(52130415000 M)资助
【分类号】：TM46

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