BMW I01 Product Information page 55

I01￿High-voltage￿Components
3.￿Electric￿Motor
The￿selector￿level￿position￿N￿is￿thus￿not￿achieved￿by￿opening￿a￿clutch￿in￿the￿transmission.￿Instead,￿the
electrical￿machine￿is￿activated￿so￿that￿it￿neither￿generates￿an￿engine￿nor￿alternator￿torque.￿One￿can
therefore￿imagine￿as￿if￿the￿coils￿of￿the￿stator￿were￿open￿and￿no￿voltage￿is￿applied￿from￿outside.￿There
is￿in￿fact￿voltage,￿generated￿by￿the￿electrical￿machine￿electronics￿–￿however,￿this￿is￿adjusted￿in￿the
amplitude,￿frequency￿and￿phase￿so￿that￿the￿rotor￿can￿rotate￿without￿a￿load￿(torque￿0 Nm).
The￿difference￿between￿the￿drive￿positions￿N￿and￿P￿is￿solely￿in￿the￿condition￿of￿the￿parking￿lock
module.￿In￿N￿it￿is￿disengaged,￿in￿P￿it￿is￿engaged.
Power￿management￿function
For￿historical￿reasons￿and￿due￿to￿an￿indirect￿relation￿to￿the￿drive￿functions,￿other￿functions￿are
integrated￿in￿the￿drive￿control￿units,￿especially￿in￿the￿EDME￿control￿unit.
For￿many￿years￿the￿electrical￿power￿management￿of￿conventional￿vehicles￿has￿been￿integrated￿as
a￿function￿in￿the￿engine￿control.￿The￿evaluation￿of￿the￿12 V￿battery￿state￿of￿charge￿via￿the￿IBS￿and
the￿consumer￿shutdown￿are￿examples￿for￿this￿power￿management￿function.￿This￿tradition￿is￿also
continued￿in￿the￿I01:￿The￿EDME￿control￿unit￿performs￿the￿power￿management￿function￿for￿the￿low-
voltage￿vehicle￿electrical￿system.￿The￿power￿management￿in￿the￿low-voltage￿vehicle￿electrical￿system
includes￿the￿following￿subfunctions:
• Determination￿of￿the￿current￿energy￿requirement￿of￿the￿electrical￿consumers￿(signals￿in￿the
form￿of￿bus￿signals,￿e.g.￿switch-on￿status￿of￿exterior￿lights￿by￿the￿Body￿Domain￿Controller
BDC)
• Determination￿of￿state￿of￿health,￿state￿of￿charge￿and￿charge￿current/discharge￿current￿of￿the
12 V￿battery￿(signals￿from￿the￿IBS)
• Controling￿the￿power￿of￿the￿DC/DC￿converter
• Monitoring￿of￿the￿standby￿current
• Switch-off￿of￿terminals￿or￿consumers￿in￿order￿to￿protect￿the￿12 V￿battery￿against￿heavy
discharge.
The￿task￿of￿the￿conventional￿12 V￿alternator￿is￿assumed￿in￿the￿I01￿by￿the￿DC/DC￿converter￿in￿the
electrical￿machine￿electronics.￿Depending￿on￿the￿power￿required,￿the￿power￿management￿in￿the
EDME￿requests￿corresponding￿power￿from￿the￿electrical￿machine￿electronics￿via￿bus￿signals.
3.3.3.￿Electrical￿Digital￿Motor￿Electronics￿(EDME)
The￿designation￿"Electrical￿Digital￿Motor￿Electronics￿(EDME)"￿reflects￿the￿electric￿motor￿in￿the￿I01
(in￿comparison￿to￿the￿conventional￿drive￿with￿a￿combustion￿engine).￿The￿manufacturer￿of￿the￿EDME
control￿unit￿is￿"Delphi￿Electronics￿Group".￿The￿manufacturer's￿internal￿designation￿is￿"DCM 3.8"￿–￿this
Delphi￿engine￿control￿unit￿is￿already￿used￿by￿other￿vehicle￿manufacturers￿and￿was￿adapted￿for￿the￿I01
in￿terms￿of￿the￿electrical￿interfaces.
The￿installation￿location￿is￿shown￿in￿the￿following￿graphic:
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