摘要
模块化多电平换流器（modular multilevel converter,MMC）中子模块（submodule,SM）的数目因工程需求正不断增加,且各种功能先进结构复杂的子模块拓扑正不断涌现,虽然已有MMC模型可大幅提高仿真效率并保证很高的仿真精度,但是已有的模型大都基于半桥和全桥子模块建立,通用性较差。为此,针对任意单端口子模块构成的MMC,以戴维南等效模型和嵌套快速同时求解算法为基础,提出一种通用的电磁暂态等效建模方法。所提出的建模方法本质上是将子模块内部节点的信息转移到外部节点以消去内部节点,从而获得降阶后的子模块诺顿或戴维南等效电路,在等效电路进行一个步长的求解之后,可以通过反解迅速更新全部子模块的内部信息。该方法统一了戴维南模型的参数求解过程,对任意结构的单端口子模块构成的MMC具有很强的通用性。同时提出一种增强型的单端口双半桥子模块拓扑,并利用所提通用算法在PSCAD/EMTDC中搭建增强型双半桥子模块MMC的等效模型,仿真验证所提模型的精度和加速比,计算各种工况下的最大相对误差,对比分析所提模型和EMTDC仿真模型的谐波误差。
The number of sub-modules （SMs） in the modular multilevel converter （MMC） based HVDC converters are increasing nowadays and new SM structures with specified functions are emerging. Although the existing MMC modeling methods can greatly improve the simulation efficiency, they are mostly focusing on the half- and full-bridge SMs based MMCs. This paper proposed a generalized electromagnetic transient （EMT） equivalent modeling approach on single-port MMCs with arbitrary SM structures. The new method was essentially derived from the nested fast and simultaneous solution algorithm. It automatically transfered the internal node information of the SMs into the interface nodes, then the reduced-order Thevenin equivalent model of each SM was obtained without losing any accuracy. Further all the SMs ware cascaded into one ultimate arm Norton or Thevenin equivalents After each time step solution, the previously eliminated internal capacitor currents and voltages ware updated, making the proposed algorithm capable of providing accurate external as well as internal steady and transient behaviors. The applicability of the proposed algorithm was validated by modeling the proposed enhanced double half-bridge sub-module （D-HBSM） based MMC topology and the EMT simulations on PSCAD/EMTDC verified the accuracy and efficiency of the proposed generalized modeling approach. The maximum relative error of the proposed model was calculated, and the error of the harmonic waves of the proposed model and the EMTDC simulation model was analyzed.
作者
赵禹辰
徐义良
赵成勇
许建中
ZHAO Yuchen;XU Yiliang;ZHAO Chengyong;XU Jianzhong(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources（North China Electric Power University）,Changping District,Beijing 102206,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第16期4658-4667,共10页
Proceedings of the CSEE
基金
国家重点研发计划项目(2016YFB0900903)
国家自然科学基金项目(51607065)~~
关键词
模块化多电平换流器
单端口子模块
诺顿和戴维南等效模型
嵌套快速同时求解算法
通用建模方法
双半桥子模块
modular multilevel converter
single-portsub-modules
Norton and Thevenin equivalent models
nested fast and simultaneous solution
generalized modeling
double-half bridge sub-module
