大功率逆变器PWM调制方法研究

Research on Pulse Width Modulation Strategy for High Power Inverter

大功率逆变器一般开关频率较低,调速范围较宽,在整个调速范围内载波比变化大,且在载波比较低时谐波含量大。通常使用一种调制方法不能满足要求,给出了一种由正弦脉宽调制、谐波消除法和方波组成的混合调制方法,在低速时使用异步正弦调制,中速时使用同步正弦调制和谐波消除法,高速时使用方波,并解决了各种方法之间的平滑切换的问题,最后进行实验验证,证明了该方法确实可行。

The switching frequency of high power inverter is extremely low, and the range of speed variation is large, which leads to the result, that the carrier ratio varies a lot and larger harmonic content bring into being in the low carrier ratio. Therefore, using one single PWM modulation mothed cannot meet the requirement, a hybrid PWM method with SPWM, SHEPWM and square waveform was presentsed, the asynchronous SPWM was used at low speed, synchronous SPWM and SHEPWM method were used at medium speed, square wave was used at high speed, and the problem of smooth transition between the various methods was solved. The result is verified through the experiment.