基于等效电流分解模型的模块化多电平交—交变换器控制方法  

A control method for modular multilevel AC/AC converter based the equivalent current decomposition model

作　　者：岳雨霏 王文[1] 唐欣[1] 汤赐[1] YUE Yufei;WANG Wen;TANG Xin;TANG Ci(School of Electrical and Information Engineering,Changsha University of Science and Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410114

出　　处：《电力科学与技术学报》2021年第5期50-60,共11页Journal of Electric Power Science And Technology

基　　金：湖南省自然科学基金(2021JJ40605);湖南省研究生科研创新项目(QL20210201);湖南省教育厅科学研究项目(153893);湖南省重点实验室开放基金(2019ZNDL001)。

摘　　要：交—交变换器作为电能变换的关键环节,在统一电能质量调节器、电力机车牵引和变频电源等领域具有重要作用,模块化多电平交—交变换器(AC/AC-MMC)是直接交—交变频中具有广阔发展前景的一种拓扑结构。首先根据单相AC/AC-MMC桥臂电气量与输入、输出间的关系,推导得到输入回路、输出回路、环流回路相互解耦的等效电流分解模型,实现输入、输出及相间环流回路的独立控制;然后,建立关于该模型及电容电压平衡控制的性能指标评估函数,提出一种基于桥臂电平数遍历模型预测控制(MPC)方法,该方法以性能指标最优为目标,选取桥臂输出电平数最优值,实现对输入电流、输出电流、环流的准确跟踪,以及对子模块电容电压的平衡控制;基于所提MPC方法,提出子模块内部损耗均衡控制优化方法,通过均匀分配子模块左、右桥臂开关状态,实现子模块内部损耗均衡分布,提高系统运行可靠性;最后,搭建PSIM仿真模型,验证所提控制方法的可行性和有效性。AC/AC converter,as the key part of power conversion,plays an important role in the unique power quality conditioner,electric locomotive traction technology and frequency variation power supply.The modular multilevel AC/AC converter(AC/AC-MMC)is a promising topology for direct AC/AC converting applications.Under the background,according to the relationship between the arm electrical quantities and the input and output of the single AC/AC-MMC,the equivalent current decomposition model of decoupled input circuit,output circuit and circulating current circuit is derived in this paper.The independent control of the three circuits is realized successfully.Then,the performance indexes evaluation function of the current model and capacitor voltage balance is established.And the model predictive control(MPC)method based on arm level traversing is proposed and utilized to realize the accurate current tracking of input current,output current and circulating current as well as the balance control of submodule(SM)capacitor voltages.The method selects the optimal arm level with the goal of the optimal performance indexes in the evaluation function.Based on the proposed MPC method,the optimized method of SM internal loss equalization control is proposed by equally distributing the switching states of the left and right arm of each SM,realizing the balanced distribution of SM internal loss,and improving the operation reliability.Finally,the PSIM simulation model is established to validate the feasibility and effectiveness of the proposed control method.

关 键 词：模块化多电平变换器 等效电流分解模型 模型预测控制 损耗均衡 

分 类 号：TM921[电气工程—电力电子与电力传动]