BMW I01, Информация о продукте

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I01�High-voltage�Components
12.�Technical�Safety�Precautions
175
2 The�systems�at�the�high-voltage�electrical�system�(EME,�REME,�KLE,�EKK,�EH)�reduce�the
currents�in�the�high-voltage�electrical�system�to�zero
3 Opening�the�switch�contactors�in�the�high-voltage�battery�unit�(controlled�by�SME)
4 Discharging�the�high-voltage�circuit,�i.e.�active�discharging�of�the�link�capacitors�(EME,�REME�and
KLE),�short-circuit�of�the�coils�of�the�electrical�machine�(EME�and�REME),�short-circuit�of�the�coils
of�the�EKK
5 Checking�the�high-voltage�system,�e.g.�as�to�whether�the�contacts�of�the�electromechanical
switch�contactors�were�correctly�opened.
Both�the�after-running�period�after�switching�off�terminal�15�and�the�shutdown�itself�can�last�a�few
minutes.�The�automatic�monitoring�functions�are�a�reason�for�this,�for�example.�The�regular�shutdown
is�interrupted�if�in�the�meantime�either�a�request�for�a�renewed�start-up�is�made�or�a�condition�has
arisen�to�request�a�quick�shutdown.
Quick�shutdown
The�overriding�aim�here�is�to�shut�down�the�high-voltage�system�as�quickly�as�possible.�This�quick
shutdown�is�then�always�carried�out�if�for�safety�reasons�the�voltage�in�the�high-voltage�system�has�to
be�reduced�to�a�safe�value�as�quickly�as�possible.�The�following�list�describes�the�triggering�conditions
and�the�functional�chain�leading�to�the�quick�shutdown.
• Accident:
ACSM�identifies�an�accident.�Depending�on�the�severity�of�the�accident�the�shutdown�of�the
high-voltage�system�is�requested�via�bus�signals.�The�SME�triggers�the�separation�of�the
switch�contactors�in�the�high-voltage�battery.�In�the�case�where�communication�via�a�data�bus
is�faulty�or�not�possible,�the�switch-off�of�the�switch�contactors�is�forced�(hard�opening).�The
switch�contactors�are�supplied�with�voltage�by�terminal�30C.�Through�the�separation�of�the
safety�battery�terminal�from�the�positive�terminal�of�the�12 V�battery,�the�voltage�supply�of�the
switch�contactors�is�also�interrupted�and�their�contacts�open�automatically.
The�EME�and�the�REME�also�receive�bus�signals�for�switching�off�the�high-voltage�system.
Both�control�units�immediately�trigger�the�active�short�circuit�of�the�electrical�machines�(short-
circuit�of�the�coils�of�the�corresponding�electrical�machine�via�the�power�semiconductor�of�the
AC/DC�converter)�and�the�active�link�capacitors�are�discharged.�If�communication�via�the�data
bus�is�not�possible,�the�shutdown�request�is�sent�via�the�separate�lines�between�ASCM�and
EME,�as�well�as�between�ACSM�and�REME.
• Overload�current�monitoring:
With�help�of�current�sensors�in�the�high-voltage�battery�unit�the�current�level�in�the�high-
voltage�electrical�system�is�monitored.�If�too�high�a�current�level�is�identified,�the�SME�control
unit�causes�a�hard�opening�of�the�electromechanical�switch�contactors.�Considerable�wear
occurs�to�the�contacts�of�the�switch�contactors�as�a�result�of�this�opening�under�a�high
current,�which�must�be�accepted�to�protect�the�other�components�from�damage.
• Protection�in�the�event�of�a�short�circuit:
In�the�high-voltage�battery�unit�there�is�an�overload�current�fuse�which�interrupts�the�high-
voltage�circuit�in�the�event�of�a�short�circuit.
• Critical�cell�state: