应用于模块化多电平变频器的电容电压脉动抑制技术综述

A Summary of Capacitor Voltage Ripple Suppression Techniques Applied to Modular Multilevel Converters for AC Motor Drives

模块化多电平变换器因其出色的模块化特性、故障冗余容错能力、良好的谐波性能、单一直流母线等优势,在中高压大功率场合广受关注。但在交流传动系统中,较大的低频电容电压纹波影响了器件的安全运行,并恶化了输出电压波形,阻碍了模块化多电平变频器在交流传动场合的使用。该文总结近年来针对传动场合的模块化多电平变频器电容电压纹波减小和抑制方案,梳理现有纹波抑制技术的主要特点,对其进行分类,对其中一些方案的优劣势进行详细分析和比较;并从工业应用角度对不同场合的最优纹波抑制方案做了判断,就未来研究方向进行探讨。

The main features of modular multilevel converter(MMC)are modularity,fault tolerant ability,voltage and power scalability,low switching frequency,and transformerless grid-connection,which make it to be one of the promising converters for medium to high-voltage,high-power applications.While in AC drive systems,the excessive capacitor voltage ripples threaten the power devices and deteriorate the output waveforms,thus hampers the application of the MMC in AC drives.This paper summarizes the capacitor voltage ripple reduction and suppression schemes for variable-frequency drive applications in recent years,and classifies them into three categories.The pros and cons of some schemes are thoroughly reviewed and compared.From the perspective of industrial application,the optimal ripple suppression schemes for different occasions are judged.Moreover,future research topics are discussed.