级联型多电平逆变器的新型直接转矩控制方法

A NOVEL DIRECT TORQUE CONTROL STRATEGY FOR CASCADED MULTILEVEL INVERTERS

直接转矩控制具有良好的调速性能,但尚未能应用于级联型多电平变频器。该文首先提出了适用于级联型多电平逆变器的空间矢量调制方法,然后将其与基于空间矢量调制的新型直接转矩控制方法相结合,从而提出了将直接转矩控制应用于级联型变频器的控制方法,并在三单元级联型变频实验装置上进行了实验验证。该文所提出的控制方法解决了级联式多电平逆变电路应用传统DTC所面临的开关状态表难于形成、开关频率不固定等问题,为直接转矩控制在级联式多电平变频器中的实用化提供了基础。

Direct torque control（DTC） has the high performance of speed control, but it hasn＇t been utilized to cascaded multilevel inverters at present. In this paper, a new space vector modulation（SVM） approach for cascaded multilevel inverters is presented firstly. Then by combining it with a new DTC approach based on SVM, the approach of using DTC to cascaded multilevel inverters is presented. And it is verified in a three-cell cascaded speed control laboratory system. The proposed approach solves the issues that switching state table is difficult to generate and switching frequency is not fixed, which is arisen from using conventional DTC to cascaded multilevel inverters. It will be of benefit to the utilization of DTC on cascaded multilevel inverters.