Bipolar pwm technique

Simulation of bipolar PWM technique

1) The modulation signal one of the top devices in one of the switching legs is kept on and the two other switching devices in the other leg are PWM operated, and during the negative half of the modulation signal, one of the bottom switching devices is kept on continuously while the other two switching devices in the other leg are PWM operated.

2) The upper and the lower switches in the same inverter leg work in a complementary manner with one switch turned on and other turned off. Since the waveform of VAB switches between positive and negative dc voltages this scheme is called bipolar PWM.