Study On New Bridgeless Pfc Converters

With the development of power electronics, the AC-DC power supplies have brought serious harmonic pollution problems to the power system. In order to reduce the harmonic pollution and improve the power factor of the converters, the power factor correction technology has been widely used.The traditional Boost PFC converter is widely used because of many advantages, such as the simple topology, high efficiency and easily achieved control strategy. However, the Boost PFC converter has low efficiency in the application of low-input voltage occasion, because of the front-end diode rectifier bridge of the converter. In order to emilinate the ill effects of the diode rectifier bridge, a class of the high efficiency PFC converters based on the resonant branch (the bridgeless Pseudo-Boost PFC converter, the novel isolated bridgeless PFC converter, the secondary side resonant Flyback PFC converter) are studies in this paper.The bridgeless Pseudo-Boost PFC converter eliminates the diode rectifier bridge, because it is constituted by a bipolar gain Pseudo-Boost converter. The working principle of the bridgeless Pseudo-Boost converter in discontinuous current mode is analyzed. The reason circuit and the bidirectional switch of the converter have been studies. Experimental results are provided with two prototypes based on the traditional Boost PFC converter and the bridgeless Pseudo-Boost PFC converter to evaluate the performance of the DCM bridgeless PFC converter.Compared with the traditional Flyback PFC converter, the novel bridgeless isolated PFC converter eliminates the diode rectifier bridge and uses secondary leakage inductance of the transformer, so that the converter get the high efficiency and low voltage stress characteristics. The secondary side resonant Flyback PFC converter has been proposed bade on the study of the novel isolated bridgeless PFC converter. It benefits advantages such as the simple topology, the high efficiency and low voltage stress.Finally, the novel bridgeless isolated PFC converter and the secondary side resonant Flyback PFC converter are used for LED driver circuits. The performance of these conveerters are compared and verified by using60W LED driver prototypes.