Automatic Voltage Controlled in Two Switch PFC Single Phase Buck Converters

Conventional single-phase power-factor-correction (PFC) rectifiers with active power decoupling capability typically require more than three active switches in their circuits. By exploring the concept of power-buffer cell, a new single-stage PFC rectifier with two active switches, one inductor and one small power-buffering capacitor is reported in this paper. The proposed converter can achieve high-power factor, wide output voltage range, and power decoupling function without using electrolytic capacitor. Additionally, an automatic power decoupling control scheme that is simple and easy to implement is proposed in this paper. The operating principle, control method, and design considerations of the proposed rectifier are also provided. A ۱۰۰۰-W prototype with ac input voltage of ۲۲۰ rms and a regulated dc output voltage ranging from ۳۰ to ۱۵۰ V has been successfully designed and simulated. The simulation results show that with only a ۱۰۰ μF power-buffering film capacitor, the proposed converter can achieve an input power factor of over ۰.۹۹, peak efficiency of ۹۵%, and output voltage ripple of less than ۵%, and THD ۲% at ۱۰۰۰-W output power.