High power factor PWM rectifiers with an analog pulse-width predictor

A single-phase PWM bridge rectifier controlled by a pulse-width predictor (PWP) to operate switching devices to realize a high power factor and to reduce the AC-side current harmonics is proposed. The PWP provides instantaneous current central with either a constant frequency carrier or a piecewisely fixed multiple-frequency carrier in one source-voltage cycle. The paper describes the control schemes and implementation of analog PWP´s, and performance characteristics of the rectifier. Unity displacement power factor was obtained and the AC-side current harmonics were reduced. Experimental results show the usefulness of the proposed method and applicability to rectifiers in UPS systems, etc