Single phase two-switch buck type AC-DC converter topology with inductor voltage control

Abstract

A single-phase ac-dc buck-type converter using only two switches is studied in detail. The converter is derived from half-bridge boost ac-dc converter using the principle of duality of electrical networks. The converter can be used with various control techniques such as sine PWM and phase control. An inductor voltage control method, capable of fast and robust input current control, is adopted here. With this control, the converter can be made to draw a near sinusoidal input current with any arbitrary power factor while the output voltage may be controlled smoothly from a maximum value to zero volts. The proposed converter is analyzed in detail, and analytical plots and expressions useful to a design engineer, have been developed. An averaged circuit model of the converter has been developed to obtain the analytical results of some of the circuit variables. This model can also be used successfully for fast and efficient circuit simulation studies. Besides providing the experimental results, the merits and demerits of the converter are also brought out.