适用于中低压MMC的改进NLC调制与电容电压控制策略  

An Improved NLC and Capacitor Voltage Control Method for Medium-/Low-Voltage MMCs

作　　者：张伟 韩俊飞[2] 钟鸣[2] 王宇强[2] ZHANG Wei;HAN Junfei;ZHONG Ming;WANG Yuqiang(Polytechnic Institute,Zhejiang University,Hangzhou 310027,China;Inner Mongolia Power Research Institute,Hohhot 010020,China;Inner Mongolia Enterprise Key Laboratory of Smart Grid Simulation of Electrical Power System,Hohhot 010020,China)

机构地区：[1]浙江大学工程师学院,杭州310027 [2]内蒙古电力科学研究院,呼和浩特010020 [3]内蒙古自治区电力系统智能化电网仿真企业重点实验室,呼和浩特010020

出　　处：《上海交通大学学报》2023年第11期1465-1476,共12页Journal of Shanghai Jiaotong University

基　　金：内蒙古自治区科技关键技术攻关计划项目(2019GG373)。

摘　　要：模块化多电平换流器(MMC)应用于直流配电网等中低压场景时输出电平数较低、谐波含量高,且电容电压易受直流母线电压波动影响而偏离额定值.针对上述问题,提出一种最近电平逼近调制与电容电压稳定控制相结合的MMC改进控制方法.首先,引入阶梯波修正量以提升MMC交流输出电平数;在此基础上,分析阶梯波修正量对电容电压的影响,提出一种基于电容电压反馈的稳定控制方法,实现子模块电压与外部电气环境的解耦控制,从而限制电容电压波动范围,提高设备安全裕度.最后,在MATLAB/Simulink仿真模型和实时数字仿真系统硬件在环测试中验证方法的正确性和有效性.The modular multilevel converter(MMC)suffers from low output level and high harmonic distortion in medium-/low-voltage applications such as direct current(DC)distribution networks.In addition,the capacitor voltage of MMC is coupled with DC bus voltage in the traditional modulation method,leading to large fluctuations of capacitor voltages and deviation from the rated value under DC bus voltage margin.In order to solve the problems above,this paper proposes an improved nearest level control method,which can increase the output level of medium-/low-voltage MMCs by introducing a step wave correction.Based on the proposed modulation method,a capacitor voltage feedback control is thus proposed to limit the range of capacitor voltage fluctuations and improve equipment safety.The effectiveness of the proposed method is verified by MATLAB/Simulink simulation and real-time digital simulation system hardware-in-the-loop test.

关 键 词：模块化多电平换流器 最近电平逼近调制 电容电压控制 

分 类 号：TM72[电气工程—电力系统及自动化]