High-voltage system energy management, function

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High-voltage system energy management, general points

The high-voltage system energy management manages provision (supply) and consumption (household) of the electrical energy. The goal is a low energy consumption and an optimal charging process.

The 12 V on-board electrical system is charged over the DC/DC converter in the power electronics control unit. The DC/DC converter operates here like an alternator in a conventional internal combustion vehicle.

 Detailed information about the 12 V on-board electrical system is contained in the function description "energy management function".

The following components are involved in the high-voltage energy management:

 Electric motor drive

 Battery management system control unit

 onboard charger

 Electric vehicle communications module control unit (for code (B54) COM-MODULE (traffic data and condition of the battery))

 Drivetrain control unit

 Power electronics control unit

 Charger feed-in socket

The interlock signal is generated by the battery management system control unit to recognize discontinuities in the high-voltage on-board electrical system and is looped over the interlock loop through components shown in the picture.

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If the interlock loop is interrupted, for example through disconnection of a CN, opening of the contactor in the high-voltage battery module occurs through discontinuity of the power supply (circuit 30C). Opening of the contactor leads to power down of the high-voltage on-board electrical system.

An active rapid discharge is also integrated into the high-voltage components since the high-voltage on-board electrical system is not de-energized is immediately after opening the contactor due to condensers in the high-voltage components.

The active rapid discharge achieves a direct voltage of U < 60 V after just t = 2 to 5 s.

If the interlock loop is interrupted during driving mode, shutoff of the high-voltage on-board electrical system only takes place after the next vehicle stop when the selector lever is set to the position "N" for vehicle standstill or the vehicle key is turned to the position Off.

 The high-voltage on-board electrical system must also be switched to remove voltage in order to perform service work without endangering an engineer by an electric shock. To do this the Service Disconnect can be drawn whereby the interlock loop is also interrupted.

The high-voltage system energy management comprises the following partial functions, which are described in separate documents:

 Energy management of high-voltage system in driving mode, function

 Energy management of high-voltage system in charging mode, function