改进冒泡排序的MMC电容电压均衡策略研究  

Study of MMC Capacitor Voltage Equalization Strategy with Improved Bubble Sorting

作　　者：刘百丰 刘军[1] LIU Baifeng;LIU Jun(School of Electrical Engineering,Shanghai Dianji University,Shanghai 201306,China)

机构地区：[1]上海电机学院电气工程学院,上海201306

出　　处：《自动化仪表》2024年第11期24-29,共6页Process Automation Instrumentation

摘　　要：模块化多电平换流器(MMC)的传统子模块电容电压均衡策略存在开关频率高、损耗大的问题。为此,设计一种改进冒泡排序的MMC电容电压均衡策略。设定梯度值,使电容电压之间增加一定的裕度。在排序过程中,若相邻两个电容电压的差值小于梯度值,则不改变子模块的索引顺序,从而减小子模块开关状态改变的次数。通过调节梯度值,控制电容电压的均衡性,并分别设计了恒定梯度值和时变梯度值这两种均压策略。利用Matlab/Simulink搭建MMC模型,对所提策略进行验证。仿真结果表明,所提策略与传统策略相比,在保证电容电压均衡的同时,能够降低子模块开关频率;同时,各子模块电容电压之间具有良好的相似性。该策略在减少MMC开关损耗的工程应用研究中具有重要意义。The traditional submodule capacitor voltage equalization strategy of modular multilevel converter(MMC)suffers from high switching frequency and high loss.For this reason,the MMC capacitor voltage equalization strategy with improved bubble sorting is designed.The gradient value is set to increase a certain margin between capacitor and voltage.During the sorting process,if the difference between two neighboring capacitor voltages is less than the gradient value,the indexing order of the submodules is not changed,thus reducing the change times that the switching state of the submodules.The equalization of capacitor voltages is controlled by adjusting the gradient value,and two voltage equalization strategies,constant gradient value and time-varying gradient value,are designed respectively.Matlab/Simulink is utilized to build the MMC model to validate the proposed strategies.The simulation results show that the proposed strategy can reduce the submodule switching frequency while ensuring the equalization of capacitor voltages compared with the traditional strategy;meanwhile,there is a good similarity between the capacitor voltages of each submodule.The strategy is of great significance in the research of engineering applications to reduce the switching losses of MMC.

关 键 词：模块化多电平换流器 子模块 最近电平逼近调制 电容电压均衡 开关频率 冒泡排序 梯度值 

分 类 号：TH-39[机械工程]