一种调制波的动态调整方法在三电平逆变器控制中的应用

Application of Dynamic Modulation Method for Modulating Wave in Three-level Inverter Control

为解决传统方法对三电平逆变器控制存在的输出电压总谐波畸变率高、中点电位不平衡等问题,设计一种调制波的动态调整方法。以二极管箝位型三电平逆变器的控制方法为研究对象,对其在运行中出现的中点电位低频波动现象进行分析,通过中点电位平衡运算实时计算出偏移量,并把偏移量叠加到中间相调制波分解成的上、下调制波上,并选用数字信号处理作为主控制器,搭建三电平逆变器电路进行实验验证。实验结果表明:该方法控制效果理想,所输出的交流电能质量能得到提高。

In order to solve the problems of high total harmonic distortion rate of output voltage and unbalance of mid-point potential of three-level inverter controlled by traditional methods,a dynamic modulation wave adjustment method is designed.With diode clamping type three level inverter control method as the research object,the potential at the point of the operation in low frequency wave phenomenon is analyzed,through the neutral voltage offset balance operation real-time calculated,and the offset stack to the middle phase modulation wave into the upper and lower modulation wave,and the use of digital signal processing(DSP)as the main controller,and set up three level inverter circuit experiment validation.Experimental results show that the control effect of this method is ideal and the ac power quality can be improved.