Single-phase high power factor pre-regulator with three-level modulation scheme

Abstract

A control scheme for the single-phase three-level pulse-width modulation active rectifier is proposed. A hysteresis current control scheme is used to draw the sinusoidal line current in phase with the mains voltage. The line current command is derived from a voltage controller and a phase-locked loop circuit. The blocking voltage of each power device is clamped to half of the DC-link voltage in the proposed active rectifier. In order to generate the three-level voltage pattern on the DC side of the active rectifier, the region detector of the line voltage, capacitor voltage compensator and hysteresis current comparator are employed in the adopted control algorithm to achieve high input power factor and low current distortion. To investigate the proposed control algorithm, the adopted rectifier is simulated and experimental tests from a laboratory prototype undertaken.