SINGLE-PHASE AND THREE-PHASE COMPATIBLE CONVERSION CIRCUIT AND VEHICLE-MOUNTED CHARGER

A single-phase and three-phase compatible conversion circuit includes an EMC module, a PFC module, a switch K and a control module. The EMC module is connected between lines A, B, C and N of a power grid and the PFC module. Three lines A, B and C are led out from the EMC module and are connected with the PFC module, and are respectively connected to a set virtual midpoint through capacitors CX, CX, and CX. The virtual midpoint is connected to a bus midpoint of the PFC module through the switch K. The control module is used for detecting a power grid input signal and controlling the state of the switch K according to the type of the power grid input signal. The common-mode noise of the three-phase conversion mode can be reduced, and the three-phase conversion mode can be controlled within a larger bus voltage regulation range.