New practical approach to input current shaping in AC-DC power converters

In principle, a distortion of a waveform shape of AC/DC converter current could be corrected by use of a fast-controlled impedance-matching transformer. Changes in the converter input impedance can be eliminated by means of the varying transformation ratio of this transformer. The paper considers a practical performance of the fast-controlled impedance-matching transformer on a basis of a non-conducting converter. It is found that the shape of current waveform can be made sinusoidal if the instant power passing through a converter is proportional to the squared instant value of the supply voltage and/or the output voltage and the output current of the converter are in inverse proportion. A non-conducting converter with alternating of parallel and series resonance meeting requirements is considered. The converter topology, an operating principle and output voltage control are described. The basics of the converter calculation and the converter current waveform modeled on computer are presented.