An improved high performance three phase AC-DC boost converter with input power factor correction

Abstract

A three-phase 3-level unidirectional AC/DC converter is proposed to achieve almost unity power factor and reduction of harmonics distortion. A power factor corrector using the hysteresis current control technique is presented to improve the power quality at the rectifier side. A high-power-factor rectifier based on a neutral point switch clamped scheme is presented. A control scheme for the proposed rectifier is propounded to draw a sinusoidal line current with nearly unity power factor, achieve balanced neutral point voltage and regulate the DC bus voltage. A hysteresis current control scheme is used to track the line current in phase with the mains voltage. The line current command is derived from a voltage controller and a phase- locked loop circuit. A capacitor voltage compensator is employed in the proposed control algorithm to achieve the balanced neutral point voltage. The effectiveness and validity of the proposed control strategy is verified through computer simulation results. The simulation result reveals that the proposed control technique offers considerable improvement in Power factor and reduction in total harmonic distortion.