BMW I01 Product Information page 72

I01￿High-voltage￿Components
4.￿Electrical￿Machine￿Electronics
Index
A
B
1
2
3
4
5
6
The￿operating￿mode￿of￿the￿DC/AC￿converter￿is￿defined￿by￿the￿EME￿control￿unit.￿The￿EME￿control
unit￿also￿receives￿the￿setpoint￿values￿(essential￿input￿variables)￿from￿the￿EDME￿control￿unit￿for￿which
torque￿(amount￿and￿sign)￿the￿electrical￿machine￿should￿supply.￿From￿this￿setpoint￿value￿and￿the
current￿operating￿condition￿of￿the￿electrical￿machine￿(engine￿speed￿and￿torque)￿the￿EME￿control
unit￿determines￿the￿operating￿mode￿of￿the￿DC/AC￿converter,￿as￿well￿as￿the￿amplitude￿and￿frequency
of￿the￿phase￿voltages￿for￿the￿electrical￿machine.￿According￿to￿these￿specifications,￿the￿power
semiconductors￿of￿the￿DC/AC￿converter￿are￿activated￿in￿sync.
In￿addition￿to￿the￿DC/AC￿converter,￿the￿power￿electronics￿also￿contains￿current￿sensors￿in￿all￿three
phases￿on￿the￿AC￿voltage￿side￿of￿the￿DC/AC￿converter.￿Using￿the￿signals￿from￿the￿current￿sensor,￿the
EME￿control￿unit￿monitors￿the￿electrical￿power￿which￿is￿used￿in￿the￿power￿electronics￿and￿electrical
machine￿and￿what￿torque￿the￿electrical￿machine￿generates.￿The￿control￿loop￿of￿the￿electrical￿machine
electronics￿is￿closed￿by￿the￿signals￿of￿the￿current￿sensors￿and￿the￿rotor￿position￿sensor￿in￿the￿electrical
machine.
The￿performance￿data￿of￿the￿electrical￿machine￿electronics￿and￿the￿electrical￿machine￿are￿coordinated
in￿development.￿The￿electrical￿machine￿electronics￿must￿be￿able￿to￿provide￿continuous￿electrical
power￿of￿75 kW￿and￿supply￿a￿maximum￿power￿of￿125 kW￿for￿a￿short￿time.￿In￿order￿to￿avoid￿overloading
the￿power￿electronics,￿there￿is￿also￿another￿temperature￿sensor￿at￿the￿DC/AC￿converter.￿If￿an￿excessive
temperature￿of￿the￿power￿semiconductor￿is￿identified￿using￿this￿signal,￿the￿EME￿control￿unit￿reduces
the￿power￿delivered￿to￿the￿electrical￿machine￿in￿order￿to￿protect￿the￿power￿electronics.￿The￿customer
is￿informed￿via￿a￿Check￿Control￿message￿in￿the￿case￿of￿a￿noticeable￿power￿reduction.￿The￿customer
receives￿the￿same￿error￿response￿(power￿reduction)￿and￿the￿same￿Check￿Control￿message￿if￿the
temperature￿of￿the￿electrical￿machine￿exceeds￿the￿permissible￿range.
Check￿Control￿symbol￿for￿power￿reduction￿due￿to￿high￿temperature￿of￿electric￿motor￿components
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Explanation
Schematic￿illustration
Schematic￿diagram￿with￿components
High-voltage￿battery
Operating￿mode￿as￿inverter,￿electrical￿machine￿works￿as￿an￿engine
Operating￿mode￿as￿rectifier,￿electrical￿machine￿works￿as￿an￿alternator
DC/AC￿converter
Current￿sensors
Electrical￿machine