一种新颖的三电平中点电压平衡控制策略

摘要

For the neutral point voltage balancing problem of the diode clamped three-level inverter,the causes of the unbalancing neutral point voltage were analysed, and the impact on the neutral point potential of the carrier's amplitude was studied, the relationship of the change of the neutral point voltage and modulation index, and the amplitude change coefficient was given, then a amplitude-scaled SPWM modulation scheme was proposed, which only requires detection of the neutral point voltage.The neutral point voltage is controlled balance by changing the amplitude of carriers without changing the modulation waves.And the validity of the modulation scheme is verified by simulation.%针对二极管钳位式三电平逆变器的中点电压平衡问题,分析了中点电压失衡的原因,从载波的角度研究了载波幅值变化对中点电压的影响,给出了中点电压变化量与调制比,以及载波幅值变化量的关系,提出了一种基于载波变幅的SPWM调制策略,该策略只需要采样中点电压,通过保持调制波不变,改变载波的幅值来实现中点电压平衡控制,最后仿真验证了上述调制方案的有效性.