PWM Converter is synonym of Active Front End Converter. As the PWM Converter is connected at the input side (front side) of the AC drive,
it is also known as an Active Front End Converter.
Active Front End Converter is used to improve the power quality by improving the power factor to unity (also settable) and
reduced current harmonics at input side. Also, it allows bi-directional power flow; the excess energy can be feed back to the grid (regenerative braking) rather than dissipating in resistors.