Single-phase power factor corrector with neutral point switch clamped topology

A control scheme for the single-phase three-level pulse-width modulation (PWM) rectifier is proposed to achieve a unity power factor, balanced neutral point voltage and constant DC bus voltage. A hysteresis current control scheme is used to track the line current in phase with mains voltage. The line current command is derived from a voltage controller and a phase-locked loop circuit. To generate a three-level voltage pattern on the AC side of the adopted rectifier, a region detector of the line voltage, a capacitor voltage compensator and a current controller are employed in the proposed control algorithm to achieve high input power factor and low current distortion. The adopted rectifier is simulated and discussed to investigate the effectiveness of the proposed control algorithm.