A novel, intelligent and flexible microcontroller-based apparatus is described to control single/three-phase symmetrical PWM (SPWM) or asymmetrical PWM (APWM)AC chopper, which offers a superior performance. The optimized PWM techniques improve the input power factor, eliminate the harmonics up to a specified order and also enable linear control of the fundamental component of the output voltage and current. The SPWM or APWM switching patterns at the specified phase angle of output fundamental voltage are obtained by the Newton–Raphson method and are implemented by the microcontroller. Through digital simulation several characteristics are investigated and compared. A prototype of the control apparatus has been built and tested. Practical verification of the theoretical predictions is presented to confirm the capabilities of the new apparatus.