随机频率PWM逆变器的分析设计

Analysis and Design of the Random Frequency PWM Inverters

应用随机脉宽调制(pulse width modulation,PWM)方法可以使逆变器的输出电压频谱呈连续分布而不影响基波分量,这样由逆变器供电的电动机的声学噪声和机械振动就会大大减小。该文提出一种用于驱动感应电机的随机频率PWM逆变器,并给出了可实现的设计程序。首先分析随机信号对逆变器输出电压频谱的影响,其次,进行相关的量化设计;最后采用Simulink仿真和实验的手段对整个系统进行了分析。仿真和实验结果表明该文提出的随机开关频率脉宽调制(random frequency PWM,RFPWM)设计方案中,逆变器输出电压的频谱是均匀随机分布的,而且声学噪声和机械振动都得到有效抑制。

Random pulse width modulation （RPWM） can make the harmonic spectrum of inverter output voltage be continuously distributed without affecting the fundamental frequency component, and thus the acoustic noise and mechanical vibration of an inverter-fed AC mot or drive are greatly reduced. A random frequency PWM （RFPWM） inverter and its practical design procedure are presented. First, the effects of the attributes of random signal on the inverter output harmonics spectrum distribution characteristics are analyzed. The quantitative design, Simulink simulation and implementation of the proposed RFPWM inverters are introduced. The simulated and measured results indicate that the harmonic peaks are greatly reduced, thus smaller acoustic noise and mechanical vibration are obtained by the proposed RFPWM scheme.