PWM控制的基本原理很早就已经提出,但是受电力电子器件发展水平的制约,在上世纪80年代以前一直未能实现.直到进入上世纪80年代,随着全控型电力电子器件的出现和迅速发展,-Power electronics device development level, which in the 1980 s have failed to achieve. Until the 1980 s, as all-controlling power electronics device to emerge and r