A hybrid bridgeless AC-DC converter topology

Bridgeless ac-dc converters are the optimal choice for many applications, as they offer many advantages such as low distorted supply current, high power factor, and improved efficiency. This paper presents a new topology for a single-phase bridgeless ac-dc converter. The proposed hybrid topology is based on integrating the inverting and non-inverting buck-boost dc-dc converters that are connected to the ac supply through an LC filter. To insure sinusoidal supply current, the proposed hybrid bridgeless ac-dc converter is operated in discontinuous current mode. The proposed converter has many merits, such as a reduced number of components, enhanced efficiency, and soft start-up capability. The operation modes and design of the proposed converter are presented. In addition, a design method is proposed for the input LC filter to minimize the voltage stress across switches. Moreover, a small signal model for the proposed converter is developed. The proposed converter topology is simulated to evaluate the dynamic behavior and verify the accuracy of the presented small signal model. Furthermore, an 850 W prototype is developed to validate the features of the proposed converter experimentally. Tight voltage regulation, sinusoidal supply current, and near-to-unity power factor operation are observed from the results, regardless of supply or load disturbances. This paper presents a new bridgeless ac-dc converter based on hybrid integration of inverting and non-inverting buck-boost dc-dc converters. The operation modes are analyzed and verified experimentally. Additionally, a novel design method is proposed for the input LC filter to minimize the voltage stress across switches.image