基于双组双调制波的PWM方法

A PWM Method Based on Double-Group-Double-Mmodulation-Wave

中点电位平衡问题是二极管箝位型三电平逆变器固有的问题。本文研究了一种能够消除中点电位低频波动的PWM调制方法的性能。该方法是通过对调制波进行分解并注入两组大小相等方向相反的零序分量,在增加载波边界值降低调制产生的开关频率的同时,依据产生的两组大小相等方向相反的平均中点电流对中点电位进行调控。本文对逆变器直流侧初始电容电压不同的情况进行了分析及研究,同时对该调制策略下的逆变器低频电压特性进行了仿真研究。仿真结果验证了该调制方法的优越性。

Neutral-point potential balancing problem is a diode clamped three-level inverter inherent problem.In this paper,the performance of the way to eliminate low-frequency fluctuations in the neutral-point potential of PWM modulation is studied.This method through decomposition of the modulation wave into two waves injected zero-sequence components with equal and opposite direction,with increasing carrier boundary values and decreasing modulation generated switching frequency,to control the neutral-point potential according to two group average neutral point current with the same values and opposite direction.The inverter DC side capacitor voltage in different initial conditions is analyzed and studied in this thesis,and the low frequency inverter voltage characteristics of this modulation strategy is also conducted a simulation study.Simulation results verifiedy the superiority of this modulation method.