Two Stage and Isolated Bridgeless AC/DC Converter

Harmonic pollution and low power factor in power systems caused by power converters have been of great concern. To overcome these problems several converter topologies using advanced semiconductor devices and control schemes have been proposed. This investigation is to identify a low cost, small size, efficient and reliable AC to DC converter. The performance of single phase and three phase AC to DC converter along with various control techniques are studied and compared. For improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input ac mains and precisely regulated dc output. This paper introduces a closed loop two stage converter and isolated bridgeless AC to DC converter with unity power factor. This power factor correction (PFC) circuit is capable to perform the AC to DC conversion without the diode bridge rectifier and able to obtain low output voltage which is more suitable to most applications. The detail small signal and steady state analysis of the converter operated in discontinuous conduction mode (DCM) are presented using the current injected equivalent circuit approach (CIECA). The proposed boost rectifier can reduce the conduction losses.