基于H-MMC的闭环预充电控制策略研究  

Research on Closed-loop Pre-charging Control Strategy Based on H-MMC

作　　者：荣飞[1] 徐爽 徐雷 黄泰霖 黄守道[1] RONG Fei;XU Shuang;XU Lei;HUANG Tailin;HUANG Shoudao(College of Electrical and Information Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学电气与信息工程学院,长沙410082

出　　处：《高电压技术》2023年第11期4584-4593,共10页High Voltage Engineering

基　　金：国家自然科学基金(51977070);湖南省自然科学基金(2021JJ30120);湖南省研究生科研创新项目(QL20220080)。

摘　　要：六边形模块化多电平变流器(hexagonal modular multilevel converter,H-MMC)作为一种直接AC/AC变流器,在中压大功率电机驱动领域具有广阔的应用前景。然而,由于H-MMC子模块众多,如何将子模块电容充电至其额定值成为亟待解决的关键问题。通过对H-MMC拓扑结构特点和充电回路进行研究,提出了一种闭环预充电控制策略。根据设定的充电功率计算电网电流参考值,基于H-MMC数学模型推导出桥臂电流参考值。采用准PR控制对桥臂电流进行跟踪以实现H-MMC的恒流充电。均压控制保证子模块电容电压的一致性。基于Matlab/Simulink搭建的预充电对比仿真结果表明所提策略具有充电时间可控、无冲击电流、一致性好的特点。最后,通过H-MMC小型样机验证了所提闭环预充电控制策略的可行性。As a direct AC/AC converter,the hexagonal modular multilevel converter(H-MMC)has broad application prospects in the field of medium-voltage and high-power motor drive.However,due to a large number of H-MMC submodules,how to charge the submodule capacitor to its rated value has become a critical issue to be solved.In this paper,a closed-loop pre-charging control strategy is proposed by studying the topological characteristics and charging loop of H-MMC.The reference of the grid current is calculated based on the set charging power.And the reference of the bridge arm current is derived based on the mathematical model of H-MMC.Quasi-PR control is employed to track the bridge arm current,so as to realize the constant current charging of H-MMC.At the same time,the consistency of the submodule capacitor voltage is ensured by the equalization control.The comparative simulation results of pre-charging based on Matlab/Simulink show that the proposed strategy has controllable charging time,no inrush current and good consistency.Finally,the feasibility of the proposed closed-loop pre-charging control strategy is verified by a small H-MMC prototype.

关 键 词：六边形模块化多电平变流器 闭环预充电 恒流 全桥子模块 准PR 均压控制 

分 类 号：TM46[电气工程—电器]