用特征网络优化开关频率的SVPWM控制方法

摘要

On the ？？′ ？？′ plane,this paper presents the space vector modulation algorithm and analyzes the distribution rule of basic vectors.A concept of characteristics quadrangle and characteristics network is used.This paper uses the basic switching to traverse the vertex of the sector only along the side of the characteristics network for optimizing switching frequency of inverter.Very small number of switching can be obtained.For a three-cell seven-level inverter and on the basis of the variations of the reference voltage,this paper finds that the characteristics quadrangle can be divided into three types and gives corresponding algorithm of the switching times.At last,the simulation results and experimental waveforms show that the algorithm is correct.The output voltage waveform is well approximate to the reference vector.Compared with the phase disposition sinusoidal modulation（PD SPWM） method,the total switching times in one reference voltage period of the proposed modulation algorithm is only 38.6% of PD SPWM.%在′′平面中研究多电平逆变器的空间矢量调制技术,分析了基本矢量的分布规律,利用特征四边形和特征网络的概念,沿特征网络遍历扇区的各个顶点,对逆变器开关频率进行优化,能得到很低的开关切换次数。本文针对三级七电平逆变器进行分析,根据参考电压调制系数的变化,将特征四边形分成三个类型,并分别给出了开关切换次数的计算方法。最后,仿真和实验结果表明该算法是正确的,且实验得到的相电压能很好地逼近参考电压。与同相层叠正弦调制算法比较,该算法开关切换次数降低到38.6%左右。