NPC三电平整流器中点电位控制方法的研究

摘要

为了解决三电平整流器中点电位不平衡问题,以NPC型三电平整流器为例,在介绍NPC型三电平整流器的主电路结构基础上,分析了中点电位不平衡问题.详细介绍了基于SVPWM控制的中点电位控制策略,通过合理地选择正负短矢量来使中点电位趋于平衡.提出了一种改进方法即基于电荷守恒的控制策略,以保持一个采样周期内流人中点的电荷等于零为原则,通过控制正负短矢量的作用时间来控制中点电位.通过计算机仿真分析验证了中点电位控制方法的有效性.%In order to solve the neutral point voltage imbalance of the three-level rectifier,NPC three-level rectifier as an example, analyzed the midpoint potential imbalance on the basis of the introduction of the main circuit. The mid-point potential control based on the SVPWM control strategy was described,and try to make the midpoint potential tending to balance through the rational choice of the positive or negative short vector. A control strategy based on conservation of charge was presented. As a principle of maintaining the charge into the mid-point zero within a sampling period, the vector of the midpoint can be controlled by controlling the positive and negative role in the short time. Simulation results verify that the proposed control plot has a good balancing effect.