High power factor PWM rectifiers with an analog pulsewidth prediction controller

A single-phase PWM bridge rectifier controlled by a pulsewidth prediction (PWP) method to operate switching devices to realize a high power factor and to reduce the AC-side current harmonics is proposed. The PWP controller provides instantaneous current control with either a constant frequency carrier or a piecewisely fixed multiple-frequency carrier in one source-voltage cycle. The paper describes the control methods and implementation of analog PWP controllers, 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.