A single-phase three-level boost type rectifier

A novel single-phase rectifier is proposed to draw a sinusoidal line current with nearly unity power factor, achieve a balanced neutral point voltage and regulate the DC bus voltage. With the aid of a neutral point clamping scheme, a three-level PWM driven voltage pattern is generated on the AC side of the proposed rectifier. To track the line current command derived from a DSP based voltage controller and a phase-locked loop circuit, a hysteresis current control scheme is used in the inner control loop. A capacitor voltage compensator is employed to achieve the balanced neutral point voltage. The experimental results based on a laboratory prototype circuit are performed to investigate the effectiveness of the proposed control scheme.