一种通用的多电平逆变器三维空间矢量调制算法研究

提出了三维空间矢量调制算法,直接将三相参考电压映射到三维空间坐标系,所得基本矢量与开关状态矢量一一对应,不存在冗余现象。该调制算法首先确定参考矢量所在单位正方体的位置,然后在这个单位正方体上寻找合成参考矢量的4个基本矢量,利用伏秒平衡原理计算各基本矢量的作用时间,最后采用七段算法实现在4个基本矢量之间的切换。该算法不需要坐标变换,参考矢量定位简单,与逆变器的电平数无关。三级七电平逆变器仿真和实验结果验证了所提出方法的正确性与可行性。

A Generalized Three-Dimensional Space-Vector Modulation Algorithm for Multilevel Converters

The proposed three-dimensional (3D) space-vector modulation (SVM) algorithm maps switching state vectors in 3 D space coordinates directly. Every basic vector only matches a switching state vector. And without redundancy phenomenon. Firstly, the location of a unit cube which includes the reference voltage vector is fixed. Secondly, in the unit cube, four basic vectors which synthesize the reference vector are confirmed. The dwelling times of the basic vectors are calculated according to volt-second balance principle. Finally, switching among the four basic vectors is implemented by seven-segment modulation algorithm. Coordinate transformation is not required in this proposed algorithm. Reference vector location is fixed simply. The proposed algorithm is also independent of the level number of the inverter. The correctness and feasibility of this proposed algorithm are verified by the simulation and experimental results of a three-cell seven-level inverter.