SINGLE-PHASE STEP-UP DOWN RECTIFIER WITH IMPROVED SUPPLY CURRENT WAVE-FORM/

The paper presents a novel single-phase rectifier with step-up/down ch aracteristics. This is fundamentally based on the cascade combination of a diode bridge and a single-ended primary inductor convertor. To si nusoidally waveshape the supply current with a near-unity power factor independent of the working conditions, buffer capacitor is operated w ith voltage reversibility for the supply by arranging the auxiliary po wer switching device and diode. The circuit operation is macroscopical ly analysed by state-space averaging method based on a DC equivalent c ircuit and such an operation is also simulated by rigorous state-space method. Moreover, the tested setup, using two insulated-gate bipolar transistors and a 16-bit microcomputer, is implemented to experimental ly investigate the steady-state and transient characteristics. The exp erimental and simulated results confirm the usefulness of the rectifie r presented.