A charging device configured to receive an AC charging power from a charging apparatus and configured to convert the AC charging power to a DC charging power for a load, the charging device comprising: a charging terminal comprising a first port, a second port, a third port, a neutral line port and a communication port, the charging terminal being configured to receive the AC charging power through the first port and the neutral line port if it is judged that the AC charging power is single-phase and to receive a first phase, a second phase and a third phase of the AC charging power through the first port, the second port and the third port, respectively, if it is judged that the AC charging power is three-phase; a first module connected with the first port and the neutral line port; a second module connected with the second port and the neutral line port; a third module connected with the third port and the neutral line port; wherein each of the first module, the second module and the third module comprises respective output terminals, the output terminals of the first module, second module and third module being connected with each other in parallel; the first module, the second module and the third module are configured to judge whether the AC charging power is single-phase or three-phase; a first auxiliary bridge arm connected between the first port and the second module; a second auxiliary bridge arm connected between the first port and the third module; and a communication module connected to the charging terminal, the first module, the second module and the third module, configured for receiving a charging signal of the AC charging power from the charging terminal and for transmitting an information about the charging signal to the first module, the second module and the third module, wherein the second module and the third module are configured to control operations of the first auxiliary bridge arm and the second auxiliary bridge arm based on the information about the charging signal; characterized in that the charging signal comprises a current value signal, wherein if it is judged that the AC charging power is single-phase and that the current value signal of the AC charging power is lower than or equal to a first current threshold value, the first auxiliary bridge arm is disabled by the second module and the second auxiliary bridge arm is disabled by the third module, so that the AC charging power is converted by the first module. a charging terminal comprising a first port, a second port, a third port, a neutral line port and a communication port, the charging terminal being configured to receive the AC charging power through the first port and the neutral line port if it is judged that the AC charging power is single-phase and to receive a first phase, a second phase and a third phase of the AC charging power through the first port, the second port and the third port, respectively, if it is judged that the AC charging power is three-phase; a first module connected with the first port and the neutral line port; a second module connected with the second port and the neutral line port; a third module connected with the third port and the neutral line port; wherein each of the first module, the second module and the third module comprises respective output terminals, the output terminals of the first module, second module and third module being connected with each other in parallel; the first module, the second module and the third module are configured to judge whether the AC charging power is single-phase or three-phase; a first auxiliary bridge arm connected between the first port and the second module; a second auxiliary bridge arm connected between the first port and the third module; and a communication module connected to the charging terminal, the first module, the second module and the third module, configured for receiving a charging signal of the AC charging power from the charging terminal and for transmitting an information about the charging signal to the first module, the second module and the third module, wherein the second module and the third module are configured to control operations of the first auxiliary bridge arm and the second auxiliary bridge arm based on the information about the charging signal; characterized in that the charging signal comprises a current value signal, wherein if it is judged that the AC charging power is single-phase and that the current value signal of the AC charging power is lower than or equal to a first current threshold value, the first auxiliary bridge arm is disabled by the second module and the second auxiliary bridge arm is disabled by the third module, so that the AC charging power is converted by the first module.