The invention relates to a vehicle-mounted charging
system of an
electric vehicle, comprising a vehicle-mounted battery, a single / three-phase power conversion module, a
direct current charging device, a charging
contactor, a
signal detection unit and a micro
control unit (MCU), wherein the single / three-phase power conversion module, the
direct current charging device, the charging
contactor, the
signal detection unit and the MCU are respectively connected with the vehicle-mounted battery; the
direct current charging device comprises a
voltage boosting module and a
voltage reduction module which can charge the vehicle-mounted battery through boosting or reducing the
voltage of an external direct current charging power supply; and the single / three-phase power conversion module directly multiplexes a vehicle-mounted
inverter of the
electric vehicle with an alternating / direct current bidirectional inversion function. In the invention, three charging
modes of the
electric vehicle are integrated in one vehicle-mounted charging
system and are flexible and selectable, the vehicle-mounted charging
system can be charged by three different charging voltages, i.e. external direct
current voltage, single-phase
alternating current voltage and three-phase
alternating current voltage, and four
alternating current charging
modes can meet the diversity requirement of the charging
modes of
current electric vehicles; and meanwhile, the original vehicle-mounted
inverter components can be multiplexed, thereby effectively reducing the cost.