A method for controlling a drivetrain of an electric vehicle during DC-charging of a traction battery. A corresponding charging circuit includes at least partially a traction inverter unit and at least partially an electric machine. The method includes controlling the traction inverter unit such that it operates as a DC-DC converter. Furthermore, a position of a rotor of the electric machine is received and based thereon, a number out of the phases of the electric machine is selected as components of the charging circuit. Additionally, the traction inverter unit is controlled such that the selected number of the phases forms part of the charging circuit. Moreover, a data processing device having means for carrying out the steps of the above method is presented. Additionally, a drivetrain and an electric vehicle are explained.