一种模块化多电平变流器的控制方法及改进的电压平衡方法  

Modular Multilevel Converter Control Method and Improved Voltage Balancing Method

作　　者：高淳[1] 姜建国[1] 

机构地区：[1]电力传输与功率变换控制教育部重点实验室、上海交通大学电气系,上海200240

出　　处：《电测与仪表》2013年第4期33-36,63,共5页Electrical Measurement & Instrumentation

基　　金：国家高技术研究发展计划(863计划)资助项目(2011AA050403)

摘　　要：模块化多电平变流器(MMC)是一种新型拓扑的多电平变流器。MMC每相桥由多个单桥模块单元级联而成,因此,如何平衡各模块内的电容电压成为一大研究热点。本文引入平均电压外环与环流内环的控制方法,在抑制环流的同时控制电容电压的绝对平衡。同时结合最近电平控制(NLC)调制方法与电容电压排序平衡的控制方法,在此基础上对排序平衡算法进行改进,引入最大电压偏差量作为排序的前提条件,避免了因模块间微小的电压关系变化引起的模块反复投切的情况,从而降低变流器的开关损耗。最后利用MATLAB/Simulink软件搭建每相20个模块的MMC逆变测仿真模型,观察MMC在本文的控制方法下的输出波形,比较改进前后的电压波动情况及开关次数。仿真结果验证了控制方法的可行性及改进算法的有效性。Modular multilevel converter （MMC） is a multilevel converter with novel topology. MMC topology is based on cascade connection of chopper-cells per leg. Therefore, how to balance voltages of capacitors in chopper-cells becomes a critical problem to research on. This paper introduces two loops to depress loop current and meanwhile control average voltage,and combines nearest level control with voltage sort control as well . Based on the control method presented in this paper, voltage sort control is improved to reduce switching operation and switching losses. MMC inverter side model with 20 cells each leg is realized by MATLAB/Simulink. Traditional balancing control and improved one are compared. The simulation results, including MMC output waveform, capacitor voltage waveform and switching signal, demonstrate the validation of the control method.

关 键 词：变流器 模块化 多电平 电压平衡 

分 类 号：TM46[电气工程—电器]