High-power-factor single-phase switch clamped rectifier

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. An AC power switch is employed in the power circuit to generate a three-level pulsewidth modulation voltage on the AC terminal. 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. To investigate the effectiveness of the proposed control scheme, experiments based on a laboratory prototype circuit are performed.