Abstract: In order to realize the simulation of marine medium voltage power system of 40kW capacity in laboratory, it is necessary to convert AC 380V of generators outputs to the stable 4kV DC output. Two level transformations were applied in the system. The bridgeless boost PFC circuit was applied in AC/DC conversion in front. Four roads of full bridge PWM converters in cascade mode were applied to boost the voltage in DC/DC conversion at the end. One of them was the phase-shift full bridge to achieve the control of adjusting voltage output. The other three bridges were common full bridge to get a stable voltage output. The simulation model of the AC/DC converter was established in MATLAB/Simulink circumstance. The simulation results show that it can output the stable 4kV DC voltage with 94.8% efficiency and 2.08% voltage ripple.

Key words: AC/DC converter, bridgeless PFC circuit, full bridge phase-shift converter, cascaded converter