Analysis, modeling and design of a True Bridgeless Single Stage PFC with galvanic isolation

Power Factor Correction (PFC) has been established for a long time to fulfill the harmonic standards. To meet the demand for a compact, efficient solution, a so-called True Bridgeless Single Stage PFC was recently introduced. By eliminating the input rectifier the efficiency is significantly improved. In addition, this topology provides galvanic isolation while employing only one single active switch. In this paper a True Bridgeless Single Stage PFC is analyzed, designed and characterized through measurements on a hardware realization. To optimize the converter with respect to efficiency, power density or cost, analytical expressions for all occurring voltages and currents in each component are derived. With the derived small signal model, the current and voltage compensator can be designed optimally, to ensure a stable and fast control behavior. In addition, a non-dissipative clamp circuit is introduced to limit the switch voltage without causing significant losses. The results of the theoretical analysis are verified by simulation and experimental measurements.