Abstract
A non-uniformly connected single-phase rectifier with a novel constantly-sampled PWM scheme is trially fabricated and experimentally examined, the ratings of which are ac 100 V input, dc 200 V output, 1 kVA and 1.0 power factor. The applied PWM scheme assures theoretically the maximum error of the actual ac current to the reference one, zero-cross distortion free and the minimum on-state and off-state time durations of main switches. Both high speed dc voltage response and less distortion of ac input current are achieved by applying feedfoward control to the dc-AVR which functions as the upper stage of the PWM. The equivalent circuit was also derived for the rectifier theoretically. The resistive component decreases linearly with increase of the feedfoward gain and is inversely proportional to the dc voltage feedback gain. 95% efficiency, 100% power factor and 2% THD were measured. For full load shut-down, 1% and 20ms were obtained respectively for the transient dc voltage overshoot and the settling time. The measured equivalent circuit is in good agreement with the theoretically predicted one. The rectifier demonstrated quick and excellent performance.
