Analysis and implementation of a three-phase four-wire switching mode rectifier based on a switch-clamped scheme

In this paper, a three-phase four-wire switching mode rectifier with a hysteresis current control strategy is proposed for improving the power factor and reducing current harmonics. The proposed circuit configuration is based on a three-level switch-clamped scheme to reduce the voltage stress of the AC power switches. Three voltage levels are generated on the phase-to-neutral voltage of the proposed rectifier. The purposes of the proposed control strategy are to correct the voltage imbalance of the DC bus capacitors, to draw the sinusoidal line currents with a nearly unity power factor and to keep the constant DC-link voltage. Applications of the proposed circuit can be used in the AC/DC/AC converters, active power filter and voltage sag compensator. Characteristics of the rectifier are examined and the validity is verified by simulation and experiments based on a laboratory prototype circuit.