The bridgeless buck power factor correction (PFC) converters feature the merits of low output voltage and high efficiency while their inherent dead angles in the input current will deteriorate the input current harmonics and power factor (PF). Aiming to reduce the dead angles, a new bridgeless buck PFC converter is proposed in this paper. Through integrating the main buck circuit and the auxiliary flyback circuit with one magnetic core, the dead angles in the input current of the proposed bridgeless buck PFC converter is eliminated so that the PF and input current harmonics are improved. The proposed bridgeless buck PFC converter is designed to operate in discontinuous conduction mode (DCM) with the merits of simple controller and nature current shaping ability. A new logic control circuit is provided. The detailed theoretical derivations and design consideration are presented. The experimental comparison among the proposed bridgeless buck PFC converter, the conventional buck PFC converter, and the conventional bridgeless buck PFC converter is displayed to validate the effectiveness of the new converter.

Bridgeless power factor correction (PFC) converter is popular for reducing the conduction losses of semiconductors. In this paper, a novel bridgeless Cuk PFC converter is proposed. Compared to the conventional Cuk PFC converter, the number of conducting semiconductors in the proposed bridgeless Cuk PFC converter is reduced, contributing to lower conduction losses. Moreover, the conduction losses in proposed converter are further improved compared with the pseudo totem-pole bridgeless Cuk PFC converter. Meanwhile, the total number of component in the proposed converter is less than other bridgeless Cuk PFC counterparts, especially for the big-volume magnetic component and electrolytic capacitor. In addition, all power switches in the proposed converter are common-ground and can be driven by one control signal, availing simple drivers. The theoretical analysis of the proposed converter is presented in discontinuous conduction mode (DCM) with the merits of nature current sharping ability, zero-current switching in semiconductors and easy control. Finally, the simulation and an 100W lab-prototype are built to validate the feasibility of the proposed bridgeless Cuk PFC converter.

Bridgeless power factor correction (PFC) converters have a reduced number of semiconductors in the current flowing path, contributing to low conduction losses. In this paper, a new bridgeless high step-up voltage gain PFC converter is proposed, analyzed and validated for high voltage applications. Compared to its conventional counterpart, the input rectifier bridge in the proposed bridgeless PFC converter is completely eliminated. As a result, its conduction losses are reduced. Also, the current flowing through the power switches in the proposed bridgeless PFC converter is only half of the current flowing through the rectifier diodes in its conventional counterpart, therefore, the conduction losses can be further improved. Moreover, in the proposed bridgeless PFC converter, not only the voltage stress of power switches is lower than the output voltage, but the voltage stress of the output diodes is lower than the conventional counterpart. In addition, this proposed bridgeless PFC converter features a simple circuit structure and high PFC performance. Finally, the proposed bridgeless PFC converter is analyzed and designed in the discontinuous conduction mode (DCM). The simulation results are presented to verify the effectiveness of the proposed bridgeless PFC converter.

A novel single-phase AC–DC bridgeless boost power factor correction (PFC) converter is proposed in this paper. This converter is constructed by paralleling a boost and a buck–boost topology. It features a solid connection between the input and output ground terminals leading to low common mode noise. Moreover, it possesses a high PFC performance which can satisfy IEC-61000-3-2 Class D Limits completely and only two semiconductors conducting in the current-flowing path. In addition, the two power switches are driven by the same control signal resulting in a simple controller. The detailed circuit operation principle in discontinuous conduction mode is presented. A simulated model established by PSIM software and a lab prototype is designed to validate the effectiveness of this proposed PFC converter.

Bridgeless power factor correction circuits are creditable for its merit of reducing conduction losses in semiconductors. In this paper, three new bridgeless single ended primary inductor converter (SEPIC) PFC converters by adopting switched-capacitor (SC) cell are proposed. Owing to the inbuilt SC cell, higher voltage gain can be generated than conventional SEPIC PFC converter. Compared to its conventional full-bridge counterparts, the proposed bridgeless SEPIC PFC converters feature a reduced conduction losses in semiconductors under the same operation parameters, contributing to improved efficiency. Furthermore, the proposed bridgeless SEPIC PFC converters adopt simple circuit structure. In addition, the proposed bridgeless SEPIC PFC converters are designed in discontinuous conduction mode (DCM) with the merits of inherently current-sharping capability and zero-current switching in semiconductors. The simulation results are provided in order to verify superiority of the proposed bridgeless SEPIC PFC converters.