High-power-factor single-phase switch clamped rectifier

This paper presents a high power factor rectifier based on neutral point switch clamped scheme. A control scheme of the proposed rectifier is proposed to dram, a sinusoidal line current with nearly unity power factor, achieve balanced neutral point voltage and regulate dc bus voltage. An ac power switch is employed in the power circuit to generate three-level pulswidth modulation (PWM) voltage on the ac terminal. 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. 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, the experimental results based on a laboratory prototype circuit are performed.