Single-stage three-phase Buck-Boost type AC-DC converter with high power factor

A new control process for single-stage three-phase Buck-Boost type ac-dc converters with high power factor, sinusoidal input currents and adjustable output voltage is proposed. This converter allows variable power factor operation, but this work focus in achieving unity power factor. The proposed control method includes a fast and robust input current controller based on a vectorial sliding mode approach. This active nonlinear control strategy, applied to this converter allows high quality input currents. Given the comparatively slow dynamics of the de output voltage, a proportional integral (Pl) controller is adopted to regulate the converter output voltage. The voltage controller modulates the amplitudes of the current references, which are sinusoidal and synchronous with the input source voltages. Experimental results from a laboratory prototype show the high power factor and the low harmonic distortion characteristics of the circuit.