说明：  三相桥双极性PWM控制Simulink仿真，叠加一些其他信号，另加一滤波器观看PWM经过低通滤波后的波形，适合电力电子初学者
(Three-phase bridge bipolar PWM control Simulink simulation, superimposed a number of other signals, plus a watch PWM filter through after the low-pass wave filter for power electronics for beginners)