BMW I01 Product Information page 69

I01￿High-voltage￿Components
4.￿Electrical￿Machine￿Electronics
Operating￿principle￿of￿the￿DC/DC￿converter
Index
1
2
3
4
The￿technology￿of￿the￿DC/DC￿converter￿in￿the￿I01￿would￿also￿enable￿the￿operating￿mode￿"Boost
mode",￿such￿as￿the￿DC/DC￿converter￿in￿the￿F04.￿However,￿this￿operating￿mode￿is￿not￿used￿in￿the￿I01.
Charging￿of￿the￿high-voltage￿battery￿of￿the￿I01￿is￿not￿possible￿using￿energy￿from￿the￿12 V￿vehicle
electrical￿system.
The￿last￿operating￿mode￿of￿the￿DC/DC￿converter￿is￿assumed￿during￿(regular￿or￿quick)￿shutdown￿of￿the
high-voltage￿system.￿For￿the￿shutdown￿of￿the￿high-voltage￿system￿the￿system￿must￿be￿discharged
to￿a￿safe￿voltage￿less￿than￿60 V￿within￿a￿specified￿time.￿The￿DC/DC￿converter￿has￿a￿discharge￿circuit
for￿the￿link￿capacitors.￿First￿of￿all,￿these￿try￿to￿transmit￿the￿energy￿stored￿in￿the￿link￿capacitors￿to
the￿low-voltage￿vehicle￿electrical￿system.￿If￿this￿does￿not￿lead￿to￿a￿sufficiently￿quick￿reduction￿of￿the
voltage,￿the￿discharging￿is￿effected￿via￿an￿active￿resistor.￿This￿way￿the￿high-voltage￿electrical￿system
is￿discharged￿in￿less￿than￿5￿seconds.￿For￿safety￿reasons￿there￿is￿also￿a￿so-called￿passive￿discharge
Explanation
Voltage￿of￿the￿high-voltage￿electrical￿system,￿about￿250 V￿to￿about￿410 V
Down￿conversion
DC/DC￿converter￿in￿the￿EME
Voltage￿of￿the￿low-voltage￿vehicle￿electrical￿system,￿about￿14 V
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