基于Y型模块化多电平换流器的柔性低频输电系统启动策略  

Start-up Control Strategy of Flexible Low Frequency AC Transmission System Based on Y-MMC

作　　者：高天 马文忠[1] 王玉生[2] 张文艳[1] 李恒硕 朱亚恒 GAO Tian;MA Wenzhong;WANG Yusheng;ZHANG Wenyan;LI Hengshuo;ZHU Yaheng(College of New Energy,China University of Petroleum(East China),Qingdao 266580,Shandong Province,China;PetroChina Planning&Engineering Institute,Chaoyang District,Beijing 100083,China)

机构地区：[1]中国石油大学(华东)新能源学院,山东省青岛市266580 [2]中国石油天然气股份有限公司规划总院,北京市朝阳区100083

出　　处：《电网技术》2025年第4期1426-1435,I0031-I0034,共14页Power System Technology

基　　金：国家自然科学基金项目(52277208)。

摘　　要：Y型模块化多电平换流器(modular multilevel converter in Y configuration,Y-MMC)的Y形结构,使其预充电及并网过程更为复杂,基于环流控制的一般启动策略不再适用。针对上述问题,设计基于模型预测控制的渐进预充电方法及无扰动并网方法,提出一种模型预测渐进启动控制策略。首先,建立桥臂电流和电容电压预测模型,通过模型预测控制改变充电电流回路、幅值和相角,实现可控充电最大有功输入,对各个桥臂渐进充电。其次,根据电流误差灵活投切子模块,逐渐平衡充电回路电势差,辅助模型预测控制抑制冲击电流。然后,协调外环比例积分控制与内环模型预测控制,通过切换外环功率和电压控制模式,实现基于Y-MMC的柔性低频输电系统无扰动并网过程。最后,通过Matlab/Simulink对双端柔性低频输电系统进行仿真分析,所提控制策略保障了启动过程较低的电流冲击和较高的充电速度,使系统平稳快速进入稳定运行状态。Due to the Y-shaped circuit structure of modular multilevel converter in Y configuration(Y-MMC),the pre charging and grid connection processes are more complex,and the general start-up control strategy based on circulating current control is no longer applicable.To address the above issues,a progressive pre charging method and an undisturbed grid connection method based on model predictive control are designed,and a model predictive progressive start-up control strategy is proposed.Firstly,establish a predictive model for the current and capacitor voltage of each branch,and use the model predictive control to change the charging current circuit,amplitude,and phase,achieving the maximum active power input of controllable charging and gradually charging each branch.Secondly,flexibly switch submodules based on current error,gradually balance the potential difference of the charging circuit,and assist model predictive control to suppress impulse current.Then,coordinate the outer loop proportional integral control and the inner loop model predictive control,flexibly switch the outer loop power and voltage control modes,and realize the undisturbed grid connection process of the flexible low frequency AC transmission system based on Y-MMC.Finally,a two terminal flexible low frequency AC transmission system was built in Matlab/Simulink for simulation analysis.The results of the simulation show that the proposed strategy ensured low current impact and high charging speed during the startup process,enabling the system to enter a stable operating state smoothly and quickly.

关 键 词：Y型模块化多电平换流器 柔性低频输电 启动策略 预充电 模型预测控制 

分 类 号：TM721[电气工程—电力系统及自动化]