蒲羿;罗永捷;熊小伏;宋勇辉;陈强;

• 1:输配电装备及系统安全与新技术国家重点实验室(重庆大学)

摘要(Abstract)：

随着基于模块化多电平换流器(modularmultilevel converter,MMC)的柔性直流输电技术逐渐向高电压等级、高传输容量发展,MMC子模块数量迅速增加,由此带来换流器运行效率低下的问题日益凸显。为实现MMC内部悬浮电容能量均衡,传统均压算法控制下的各桥臂子模块高频投切,会产生大量无效开关损耗。针对这一问题,提出一种低开关损耗的MMC调控方法。首先,基于MMC运行原理,推导了子模块投切、轮换与电容电压暂态增量的数学关系,从而提出对电容电压序列收敛性的预测方法。基于此,提出一种改进的低开关频率均压控制策略。该策略根据对桥臂内子模块电压序列的收敛性的预测结果,在每个离散控制周期初始时刻动态调控子模块轮换数,以消除非必要的子模块轮换。与现有均压策略相比,该策略能在不降低均压效果的前提下,有效降低开关频率,有助于提高系统的运行效率。基于实际柔性直流输电工程参数,在PSCAD/EMTDC上搭建仿真模型,对所提出改进型方法和现有低开关频率控制方法进行了对比验证。

关键词(KeyWords)： 模块化多电平换流器;均压控制;开关频率;电压收敛性

Abstract:

Keywords:

基金项目(Foundation): 国家自然科学基金项目(51707027)~~

作者(Author): 蒲羿;罗永捷;熊小伏;宋勇辉;陈强;

Email:

DOI: 10.13335/j.1000-3673.pst.2019.2465

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