Three-Phase Bridgeless AC/DC PFC with LLC Resonant Circuit for High Efficiency and Low Input Current THD

To convert the three-phase AC power to DC power, conventional power conversion system has a 2-stage configuration which consists of the AC/DC PFC and isolated DC/DC converter system. However, this configuration has the disadvantage that the volume of the system increases and the efficiency decreases due to two-times of the power conversion process. Therefore, in this paper, we propose a three-phase bridgeless PFC system with LLC resonant circuit for improvement of power factor, input current THD and efficiency through soft switching.