一种新型多电平直接脉宽调制方法

在研究了多电平逆变器模型及其脉宽调制(PWM)算法原理的基础上,提出了一种新型的适用于各种电平数目逆变器的直接PWM方法,分析了这种PWM方法的基本原理,给出了算法实现的原理框图,最后使用PSCAD仿真软件做了仿真研究,仿真结果验证了算法的正确性和有效性.文中提出的PWM算法的基本思想是由三相参考电压直接确定逆变器各个桥臂电路输出的开关函数及其作用规律,因此称之为直接PWM算法.与基于载波调制的多电平PWM算法和多电平SVM算法相比,该算法具有原理简单、实现容易、运行速度快、占用CPU时间少等优点.

A NOVEL DIRECT PWM METHOD FOR MULTILEVEL INVERTERS

The paper presents a novel pulse width modulation (PWM) method applicable to any number level inverters, based on the study of model of multilevel inverter and principle of PWM method. The basic principle of this PWM method is analyzed, and the principle block diagram for the method realization is given. The PWM method is simulated by PSCAD software and the results demonstrate the accuracy and validity of the proposed method. The basic idea of this PWM method named direct PWM method in this paper is to attain switching state and its operation rules of each bridge of multilevel inverters through three-phase voltage reference. Compared with the carrier-based multilevel PWM method and multilevel SVM method, this method has the advantages of simplicity in principle, easiness in implementation, high speed in execution and less occupancy of CPU.