An improved bridgeless SEPIC PFC rectifier with optimized magnetic utilization, minimized circulating losses, and reduced sensing noise

In this paper, an improved bridgeless single-ended primary inductance converter (SEPIC) power factor correction (PFC) rectifier is introduced. By introducing an additional output diode into conventional bridgeless SEPIC PFC rectifier, an undesired capacitive coupling loop is removed, not only eliminating the circulating loss but also reducing the sensing noise. Moreover, an integrated magnetics with symmetrical structure could be utilized so as to reduce the system size and increase the circuit power density. The operation principle of the proposed converter is investigated, and simulation results are provided. A 100-W prototype with 110V_rms input line voltage and 50V dc output voltage is built and tested. A peak efficiency of 91% and power factor above 0.98 are achieved under 100kHz switching frequency operation condition.