A simple multiple pulsewidth modulated AC chopper

A simple multiple pulsewidth modulated (MPWM) AC chopper using power transistors for 3-amp;phi; power control is discussed. 120amp;deg; chopping period is used for main transistors so that the circuit can accommodate resistive and lagging or leading power factor loads. Only 1-amp;phi; sensing is used for 3-amp;phi; control. An alternate economical power and control scheme for 3-amp;phi; MPWM AC choppers suitable only for resistive loads is also suggested. The experimental results for 12 choppings per cycle are give