BMW I01 Product Information page 73

I01￿High-voltage￿Components
4.￿Electrical￿Machine￿Electronics
High-voltage￿power￿management
The￿power￿management￿for￿the￿high-voltage￿electrical￿system￿includes￿two￿subfunctions:￿one￿for
driving￿and￿one￿for￿charging￿mode.￿In￿driving￿mode￿the￿energy￿flows￿from￿the￿high-voltage￿battery
to￿the￿high-voltage￿consumers￿are￿coordinated.￿The￿following￿steps￿are￿performed￿by￿the￿EME￿and
repeated￿constantly:
1 Query￿of￿the￿power￿available￿from￿the￿high-voltage￿battery￿(signal￿source:￿SME)
2 Query￿of￿the￿requested￿power￿from￿the￿electric￿motor￿(signal￿source:￿EDME)
3 Query￿of￿the￿requested￿power￿for￿climate￿control￿(electric￿heating,￿EKK,￿IHKA)
4 Decision￿on￿the￿distribution￿of￿the￿electrical￿power￿and￿communication￿to￿the￿control￿units￿of￿the
consumers.
For￿charging￿mode￿the￿task￿of￿the￿high-voltage￿power￿management￿is￿different:￿It￿controls￿the￿energy
flow￿from￿outside￿the￿vehicle￿via￿the￿EME￿and/or￿the￿convenience￿charging￿electronics￿KLE￿to￿the
high-voltage￿battery￿and￿if￿required￿to￿the￿electric￿heating￿or￿to￿the￿EKK.￿The￿procedure￿constantly
repeated￿in￿the￿EME￿consists￿of￿the￿following￿individual￿steps:
1 Query￿of￿the￿available￿power￿from￿outside￿(signal￿source:￿LIM)
2 Query￿of￿the￿power￿which￿the￿high-voltage￿battery￿can￿use￿(SME)
3 Query￿of￿the￿power￿which￿is￿required￿for￿the￿climate￿control￿(IHKA)
4 Requesting￿the￿necessary￿power￿from￿the￿(EME/KLE)
5 Communication￿of￿the￿available￿partial￿powers￿to￿the￿receiver￿of￿the￿high-voltage￿battery￿(SME
control￿unit)￿and￿heating￿and￿air-conditioning￿system￿(IHKA￿control￿unit).
The￿externally￿available￿power￿cannot￿be￿at￿a￿high￿level;￿it￿is￿restricted￿by￿the￿power￿network￿and￿the
EME/KLE.￿Therefore,￿the￿available￿power￿must￿be￿queried￿first￿before￿it￿can￿be￿distributed.￿The￿high-
voltage￿battery￿cannot￿absorb￿much￿power,￿for￿example￿due￿to￿its￿state￿of￿charge,￿which￿is￿why￿this
value￿is￿also￿queried￿first.￿Depending￿on￿the￿temperature￿of￿the￿high-voltage￿battery￿or￿on￿a￿heating￿or
an￿air-conditioning￿request￿by￿the￿driver,￿the￿heating￿and￿air-conditioning￿system￿also￿needs￿electrical
power,￿whose￿amount￿is￿the￿third￿important￿input￿signal￿for￿the￿high-voltage￿power￿management￿in￿the
charging￿mode.￿Using￿this￿information￿the￿externally￿requested￿power￿is￿controlled￿and￿distributed￿to
the￿consumers.
Voltage￿supply￿for￿other￿high-voltage￿consumers
The￿electrical￿machine￿electronics￿supplies￿voltage￿not￿only￿to￿the￿electrical￿machine.￿The￿high-
voltage￿consumers￿"EKK"￿and￿"electric￿heating"￿also￿receive￿their￿high-voltage￿supply￿from￿the
electrical￿machine￿electronics.
However,￿there￿is￿no￿complex￿control￿function￿in￿the￿electrical￿machine￿electronics.￿Instead,￿the
electrical￿machine￿electronics￿serves￿as￿a￿simple￿distributor￿of￿the￿high-voltage￿direct￿current￿voltage,
which￿is￿provided￿by￿the￿high-voltage￿battery.￿In￿order￿to￿protect￿the￿high-voltage￿cable￿for￿the￿two
high-voltage￿consumers￿against￿overloading￿in￿the￿event￿of￿a￿short￿circuit,￿the￿electrical￿machine
electronics￿contains￿a￿high-voltage￿fuse￿for￿the￿EKK￿and￿a￿high-voltage￿fuse￿for￿the￿electric￿heating.
Both￿high-voltage￿fuses￿have￿a￿nominal￿current￿level￿of￿40 A.
The￿distribution￿and￿the￿electrical￿connection￿of￿the￿fuses￿are￿already￿shown￿in￿the￿chapter￿"High-
voltage￿connections".
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