A buck-type low-power rectifier with high-quality waveforms

In this paper a buck-type rectifier for use in low-power levels is presented, whereby high-quality waveforms at both ends of the rectifier are achieved. The methodology involves both an accurate shaping of the dc current by using two self-commutated switches (IGBTs), and a reinjection circuit connecting both the ac and dc sides. It is demonstrated, theoretically and experimentally, that this methodology produces pure sinusoidal currents flowing from the ac supply, regardless of both the firing angle of the bridge thyristors and the nature of the load (resistive, inductive or capacitive). Also, when comparing the proposed topology with similar ones, it is concluded that the proposed buck-type rectifier looks promising regarding simplicity, general use and reliability.