优化开关频率的三电平四桥臂逆变器矢量控制

Optimized Switching Frequency Three-Level Four-Leg Inverter Vector Control

三电平四桥臂逆变器基本空间矢量数目多,并且具有冗余分量,给绝对开关状态的选择带来了困难.本文提出一种优化开关频率的3-D SVM控制方法,将abc坐标系下的三相参考电压归一化处理,确定参考矢量所在的小立方体,计算参与矢量合成所需的基本作用矢量及开关序列,给出了满足最低开关切换次数的映射关系.采用MATLAB/simulink仿真平台对该方法进行了仿真验证.结果表明该方法能够有效地跟踪参考矢量的变化,并降低每个采样周期内的开关次数.

The number of space vectors in three-level four-leg inverters is large and the vectors contain redundant components,which make the selection of absolute switch states hard.This paper proposes a 3DSVM technique with optimized switching frequency.Firstly,the three-phase reference voltage vectors in abc coordinate are normalized and the tetrahedron,which the reference vector points to,is selected.Secondly,the action vectors for reference-vector synthesis and the switching sequence are found.Finally,the relations to satisfy the minimum switching time are given.The simulations based on MATLAB software are performed,and the results show that the output voltages follow the reference voltage vectors well and the switching time in every sample period is reduced.