Increased frequency resolution of active rectifiers using fractional digital PWM

A fractional digital PWM (DPWM) scheme is investigated for carrier-based active rectifiers with the goal of increasing the fundamental frequency resolution attainable with traditional DPWM. The fractional DPWM technique overcomes frequency resolution drawbacks inherent in DPWM. In practice, the fractional DPWM technique will improve the frequency resolution of active rectifiers by a factor of 20 to 50. The augmented resolution allows for a much tighter tracking of the source frequency without increasing the cost of the microcontroller, leading to an active rectifier with enhanced power quality and performance.