BMW 3: Introduction
The Electrical Machine Electronics (EME) is primarily used as control electronics for the electrical machine. It is also responsible for converting the direct current voltage from the high-voltage battery unit (up to approximately 354.2 V DC) into a three-phase AC voltage for electrical machine motor operation. Also, when the electrical machine works as a generator, the Electrical Machine Electronics converts the three-phase AC voltage of the electrical machine into a direct current voltage and can charge the high-voltage battery unit. This happens, for example, during brake energy regeneration (energy recovery). For these two operating modes a bidirectional DC/AC converter is necessary which can work as both an inverter and a rectifier.
The DC/DC converter which is also integrated in the Electrical Machine Electronics ensures the voltage supply to the 12 V vehicle electrical system.
The entire Electrical Machine Electronics of the G20 PHEV is located in an aluminum housing. The control unit, the bidirectional DC/AC converter and the DC/DC converter for voltage supply of the 12 V vehicle electrical system, are located in this housing.
The EME control unit also assumes additional tasks. For example, the high-voltage power management, which manages the available high voltage from the high-voltage battery unit, is also integrated in the EME. In addition, the EME has various output stages, which are responsible for the activation of 12 V actuators.
The Electrical Machine Electronics is a high-voltage component
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High-voltage component warning sticker
Each high-voltage component has on its housing an identifying label that enables Service employees and vehicle users to identify intuitively the possible hazards that can result from the high electric voltages used.
Only Service employees who satisfy all the prerequisites are permitted to work on the designated high-voltage components: suitable qualifications, compliance with the safety rules, procedure following the exact repair instructions.
For reasons of high-voltage safety the Electrical Machine Electronics must not be opened or otherwise dismantled.
In the event of a fault, the complete Electrical Machine Electronics are always replaced.
After the Electrical Machine Electronics have been replaced they must be put into operation with help of the diagnosis system. Observe the information in the repair instructions.
Technical data
Electrical machine electronics
Power electronics
DC/DC converter
Installation location
G20 PHEV, installation location of the Electrical Machine Electronics
The Electrical Machine Electronics are installed on the rear left in the engine compartment when looking from the front.
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Connections
The connections at the Electrical Machine Electronics can be divided into
four categories:
Low-voltage connections
High-voltage connections
Connection for potential compensation line
Connections
Low-voltage connections
In the low-voltage connector at the Electrical Machine Electronics the
following lines and signals are
combined:
Terminal 30 from the hybrid power distribution box
Terminal 30 from the f
High-voltage connections
At the Electrical Machine Electronics, there is a total of three high-voltage
connections to connect the
lines for other high-voltage components. The connections for the electric A/C
compressor and
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Installation locations and connections
G20 PHEV, heater circuit
Electric coolant pump
Connection to the coolant circuit
Heat exchanger for heating system
Electrical heating
Electrical changeover valve
Connections at the electric heating
Coolant feed line (from the electric coolant pump)
Coolant feed line (to the heat exc
Terminal control for driving readiness
Terminal control from driver's view
Vehicle condition - DRIVING
Vehicle condition - RESIDING
Vehicle condition - PARKING
Transitional condition for establishing driving readiness,
ending driving readiness or Check/Analysis/Diagnosis
Transitional condition with stationary functions
Actua
