Single-stage input current shaping technique with voltage-doubler rectifier front-end

Abstract

A single-stage input-current-shaping (S.sup.2 ICS) converter of the present invention integrates a voltage-doubler-rectifier front-end with a DC/DC output stage. Two families of voltage-doubler S.sup.2 ICS converters are disclosed. In one family, a 2-terminal dither source is provided between a boost inductor and a common input terminal of a storage capacitor and the DC/DC output stage. The 2-terminal dither source includes two paths connected in parallel: a first path for charging and a second path for discharging the boost inductor at a high frequency (HF). In the other family, a 3-terminal dither source includes a third terminal coupled to a pulsating node of the DC/DC output stage. In the 3-terminal dither source, the HF charging path of the boost inductor is coupled between the boost inductor and the pulsating node of the DC/DC output stage, while the HF discharging path of the boost inductor is coupled between the boost inductor and the common input terminal of the storage capacitor and the DC/DC output stage. Due to the voltage-doubler-rectifier front-end, reduction of line-current harmonics can be achieved with a higher conversion efficiency, as compared to a corresponding S.sup.2 ICS converter with a conventional full-bridge rectifier. In addition, a converter of the present invention requires storage capacitors of a lower voltage rating and a smaller total capacitance than the conventional S.sup.2 ICS counterpart. The present invention thereby reduces the size and the cost of the power supply.