Electric Motor - Electric Motor - Overview

Description and Operation General information NOTE: The relevant precautions and safety measures in accordance with the workshop literature must be followed before starting work. NOTE: The electric motor is only available as a unit combined with the TCM (transmission control module) with integrated power electronics. Refer to the current workshop literature for further information. The coolant-cooled electric motor is a 3-phase AC motor with an output of 107 kW. It is designed as a permanent magnet synchronous motor. This means that the windings are located in the stator and the permanent magnets are integrated into the rotor. The windings are actuated by the TCM with integrated power electronics to create a rotating magnetic field. To enable the correct stator coil to be actuated, the power electronics need information about the position of the rotor. This information is determined using Hall sensors and sent to the power electronics. For regenerative braking, the power electronics configure the electric motor to operate as a generator. The rotating rotor induces AC voltages in the stator windings, which are rectified in the power electronics. TCM with integrated power electronics The TCM with power electronics and the electric motor are screwed together and form a single unit, which can only be replaced as an entire unit in case of failure. It is water cooled and directly connected to the high voltage battery by the high voltage cables. The power electronics has the following tasks: Actuating the electric motor Distributing the voltage from the high-voltage battery to the individual high-voltage components Item Description 1 TCM with integrated power electronics 2 High volt connectors coming from the high voltage battery 3 Cabin coolant heater fuse Comments: Interior heating electric PTC (positive temperature coefficient) booster heater 4 Electric A/C compressor fuse 5 DC (direct current)/DC converter fuse 6 Protective circuit connector 7 Cabin coolant heater high voltage connector Comments: Interior heating electric PTC booster heater 8 Electric A/C compressor high voltage connector 9 DC/DC converter high-voltage connector To actuate the electric motor, the power electronics convert the incoming DC voltage into an AC voltage. It communicates with the CAN(controller area network) via the EV HS-PCM (powertrain control module) data bus (high voltage components). Based on these specifications, the windings in the electric motor are actuated, thus regulating the speed of the electric motor. In coasting mode or for regenerative braking, the PCM sends information about the required braking power to the power electronics via the EV HS-CAN data bus (high voltage components). The power electronics then actuate the electric motor so that it operates as a generator with the specified power. The AC voltage supplied is converted into a DC voltage in the power electronics, in order to charge the high voltage battery. In the power electronics, the voltage coming from the high voltage battery is distributed to the following high voltage components using three fuses: Cabin coolant heater (interior heating electric PTC booster heater) Electric A/C compressor DC/DC converter NOTE: The fuses can be renewed during servicing. Refer to the current workshop literature for further information.