BMW I01 Product Information page 74

I01￿High-voltage￿Components
4.￿Electrical￿Machine￿Electronics
Activation￿of￿the￿parking￿lock
The￿electromechanical￿parking￿lock￿of￿the￿I01￿including￿its￿operating￿principle￿and￿activation￿is
described￿in￿detail￿in￿the￿section￿"Electric￿motor".￿Therefore,￿only￿the￿key￿aspects￿of￿the￿activation￿are
mentioned￿here.￿The￿electrical￿machine￿electronics￿contains￿the￿following￿components￿required￿for
the￿parking￿lock:
• Output￿stage￿for￿the￿activation￿of￿the￿electric￿motor￿in￿the￿parking￿lock￿module
• Current￿sensor￿for￿the￿monitoring￿of￿the￿electric￿motor
• Evaluation￿electronics￿for￿sensor￿signals.
The￿output￿stage￿for￿the￿activation￿of￿the￿electric￿motor￿only￿comprises￿one￿bridge￿circuit￿of￿power
transistors.￿It￿is￿able￿to￿supply￿the￿electric￿motor￿with￿the￿necessary￿current￿of￿about￿3 A￿to￿4 A￿during
the￿operation,￿as￿well￿as￿supply￿the￿high￿starting￿current￿for￿the￿electric￿motor￿of￿up￿to￿10 A.￿The
bridge￿circuit￿is￿designed￿so￿that￿it￿will￿not￿suffer￿damage￿in￿the￿event￿of￿a￿short￿circuit￿at￿the￿output
(current￿limitation).￿In￿order￿to￿protect￿the￿electric￿motor￿and￿the￿line￿against￿overloading,￿the￿EME
control￿unit￿monitors￿the￿current￿level￿of￿the￿output￿stage￿and￿also￿restricts￿it￿if￿required.￿For￿this
purpose,￿the￿output￿stage￿contains￿a￿current￿sensor,￿whose￿signal￿is￿evaluated￿by￿the￿EME￿control
unit.
The￿two￿redundant￿position￿sensors￿in￿the￿parking￿lock￿module￿are￿hall-effect￿sensors.￿The￿EME
control￿unit￿provides￿the￿voltage￿supply￿for￿the￿sensors.￿It￿also￿reads￿in￿the￿signals￿from￿the￿position
sensors,￿validates￿their￿plausibility￿and￿evaluates￿them.￿Using￿the￿signals￿of￿the￿position￿sensors
the￿EME￿control￿unit￿determines￿the￿status￿of￿the￿parking￿lock￿(engaged/disengaged)￿and￿makes
the￿status￿available￿as￿a￿bus￿signal.￿This￿is￿read￿in￿for￿example￿by￿the￿EDME￿control￿unit￿where￿the
transmission￿functions,￿e.g.￿engaging￿the￿drive￿positions,￿are￿calculated.
The￿familiar￿graphic￿from￿the￿chapter￿"Electric￿motor￿>￿Transmission >￿Parking￿lock"￿shows￿the
electrical￿interface￿between￿the￿parking￿lock￿module￿and￿the￿electrical￿machine￿electronics.
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