中点电压偏移对SVM控制的三电平逆变器的影响及补偿措施

Effect of Neutral-Point Voltage Unbalance of Three-Level Inverter Controlled by SVM and Compensation Method

简要介绍了三电平逆变器的传统SVM控制算法。针对逆变器负载运行时,负载动态特性对于三电平逆变器的中点电压的影响,以及由中点电压偏移造成的空间矢量图的变化,引入中点电压前馈控制方法,进行新的矢量分区和作用时间计算,从而改进逆变器带负载时的输出电流波形。在Matlab软件平台上进行仿真,结果表明改进的SVM得到的输出电流波形较传统的SVM控制方法下的输出电流波形有明显的改善。

The traditional SVM algorithm for three-level inverter was briefly described firstly. When three-level inverter is loaded, the load characteristics have an obvious effect on the neutral-point voltage, which leads to the distortion on output voltage waveform of the inverter. By computation, the angle and amplitude errors of little vectors and middle vectors were acquired in each subsection. Aimed at these defaults, a novel SVM algorithm with neutral-point voltage feed-forward was proposed. By using new vector selection and duration algorithm, the inverter output current was improved in harmonic content and amplitude. The simulation was carried out by using Matlab platform. Computer simulation results verify that the output current waveform has been greatly improved compared with the conventional SVM control algorithm, so proposed control algorithm is suitable for three-level inverter.