Novel Single-Phase Buck+Boost PFC Rectifier with Integrated Series Power Pulsation Buffer

This paper introduces a novel integrated series power pulsation buffer (iSPPB) concept for a single-phase AC-to-DC two-switch buck+boost PFC rectifier to compensate the fluctuating power mismatch between the AC input and the DC output. Accordingly the DC-link capacitance can be drastically reduced and an electrolytic-capacitor-Iess PFC rectifier system featuring a higher power density and an increased lifetime is obtained. The proposed iSPPB concept consists of a simple full-bridge circuit with a buffer capacitor and is placed in series with the buck-boost inductor thus no additional inductive component is required for the iSPPB realization. The basic operating principle of the buck+boost PFC rectifier with iSPPB is investigated and the characteristic waveforms are presented. As shown in the analysis due to the employment of the iSPPB also the maximum buck+boost inductor current is reduced which compared to the conventional rectifier system without iSPPB allows to further downsize the inductive component. Consequently the major drawbacks of conventional single-phase PFC rectifiers are eliminated. Furthermore the control structure is presented and the proper operation is verified based on a closed-loop circuit simulation. Finally the proposed buck+boost PFC rectifier with iSPPB and a conventional two-switch implementation employing electrolytic capacitors are quantitatively compared by means of simple performance indices.