一种适用于级联H桥型逆变器的新型PWM脉冲模型

A Novel PWM Model for Cascaded H-bridge Converters

从级联H桥型逆变器的脉冲本质出发,引入一组表征脉宽调制(pulse width modulation,PWM)特性的中间变量,称之为脉冲净面积(pulse net area,PNA),以此为基础讨论级联H桥中PWM脉冲模型,给出基于不同优化约束条件下的PWM模型和相关实现,提出三种改进型PWM的实现方法。实验结果表明,该脉冲模型正确可行,可用于评估PWM调制方法的特性,并从提高系统的谐波特性和降低开关损耗等方面实现对PWM调制方法的优化。

This paper analyzed the essence of switch pulses and introduced a group of variables named pulse net area（PNA）.Based upon the research on the PNA,the pulse width modulation（PWM） model for cascaded H-bridge converters was established.This model can be used to evaluate and optimize PWM methods.Three improved PWM methods were introduced.Experiment results proved the correctness and feasibility of the PWM model applied to the further research on the modulation method for cascaded H-bridge converters.It is practical to use the proposed model in establishing new modulation methods,reducing switching cost,and assessing the characteristics of certain modulation method for cascaded H-bridge converters.