一种具有中点平衡功能的三电平异步电机直接转矩控制方法

对三电平逆变器供电异步电机直接转矩控制(DTC)系统进行了研究。以固定合成矢量为基础，提出了一种三电平异步电机DTC控制方法，并使用基于三相输出电流方向及中点不平衡方向检测的中点平衡Bang-Bang控制方法来控制中点电位平衡。使用文中的DTC方法，可以抑制三电平直流侧中点不平衡，限制输出电压dv/dt，减小开关损耗，同时获得良好的电机调速特性。实验结果证明了该控制方法的可行性。

A DTC Algorithm of Induction Motors Fed by Three-level Inverter With Neutral-point Balancing Control

The paper mainly focuses on the direct torque control (DTC) system of induction motors fed by three-level inverter.Based on the fixed synthesizing vectors,an induction motors DTC method fed by three-level inverters is proposed. And then,the neutral-point balancing Bang-Bang control method,which is based on the detection of each phase leg current's and neutral-point voltage ripple's direction,is employed to make neutral-point potential balance.With the proposed DTC strategy,the neutral-point voltage unbalance,the dv/dt of output voltage and the switching loss is restrained. Furthermore,it does not deteriorate the performance of DTC schemes.The experimental results verify the correctness and feasibility of the proposed control scheme.