A new active power factor correction method for single-phase buck-boost AC-DC converter

A current mode control technique suitable for a single-phase AC-DC converter is presented. It is shown that application of this technique to a single-phase AC fed buck-boost AC-DC converter yields a sinusoidal input current waveform at unity input power factor. The proposed converter retains this property even under distorted AC input voltage conditions. In addition, the proposed technique offers definite advantages over the conventional boost converter and it is easy to understand, is easy to implement, and draws sinusoidal input current from the AC source for any DC output voltage condition. That is, the DC output voltage may be less than the peak AC input voltage. Furthermore, the proposed technique attenuates substantially the low-frequency harmonic components of the rectifier input current while shifting the unwanted harmonic components near the switching frequency. These unwanted high-frequency components can be easily filtered out using lightweight filter components