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EME: Electrical machine electronics

NOTE: To reach the connections of the electrical machine electronics (EME), part of the luggage compartment trim panel will first need to be removed. A then visible lid must also be removed, from which an opening for the Service arises. The lid is fastened by a screw connection to the body and is also sealed by a rubber seal.

The connections on the electrical machine electronics can be organized in the following categories:

G11149397Courtesy of BMW OF NORTH AMERICA, INC.
Item Explanation
1 Electrical machine electronics
2 Connection communication of vehicle
3 High-voltage connection intermediate circuit (high-voltage battery and battery management electronics)
4 High-voltage connection for range extender, starter motor generator or convenience charging electronics
5 Connection electrical machine (U, V, W)
6 Connection of rotor position sensor and temperature sensor (rotor, stator)
G11149398Courtesy of BMW OF NORTH AMERICA, INC.
Item Explanation
1 Electrical machine electronics
2 Power socket, battery negative connection (potential compensation)
3 Power socket, battery positive connection (potential compensation)
4 Coolant line exhaust
5 Coolant line intake
6 High-voltage connection of electric A/C compressor
7 High-voltage connection of electric auxiliary heater
8 High-voltage connection for AC charging

The electrical machine electronics is liquid-cooled and integrated in its own low temperature cooling circuit. The electric coolant pump is activated depending on the current cooling requirement. During this the coolant takes on a maximum temperature of approx. 85 °C (reverse).

Already when terminal 15 is switched on, the power electronic circuits of the electrical machine electronics function. In this way, the high-voltage electrical system (electric A/C compressor and electric auxiliary heater) and the 12 V vehicle electrical system are supplied with energy by the DC/DC converter. If due to the resulting heat a cooling requirement is detected, the coolant pump is switched on.

While the high-voltage battery is being charged, the power electronics in the charging electronics functions. Due to the high electrical power, which is being implemented in the charging electronics, heat also arises. This must be discharged. This is why while charging during a respective high temperature, the electrical machine electronics switches on the electric coolant pump.