Input current wave‐shaping technique using inductor voltage sensing for high‐power‐factor flyback rectifier

In this paper, a simple input current waveform shaping method for a rectifier with a high power factor using the induced voltage of a flyback transformer is proposed. The duty ratio of the present shaping circuit is obtained by comparison of the integration signal of the rectified induced voltage and the ramp carrier waveform with a negative slope. By means of the proposed method, the input voltage sensor, current control loop, multiplier, and inductance current sensor can be eliminated, simplifying the control circuit. In order to confirm the proposed method, a flyback rectifier circuit for 100 W is fabricated for an experimental investigation. The results confirm that the input current waveform of the rectifier becomes closer to a sinusoidal shape and harmonic components become smaller by the use of the present shaping method. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(10): 26–35, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10188