In motor vehicles or other means of transportation, on- board networks form the networking and communication infrastructure for all electrical and electronic components of a vehicle. Such an on-board network connects the on-board computer with the control units, sensors and actuators via a field bus and supplies and provides the supply voltage for energy-consuming components such as the cooling system, seat heating, fan, compressor and other consumers. The classic supply system is the 12 V on-board network, which is increasingly being supplemented by on-board networks with higher voltages.
The concept of on-board networks
On-board networks are implemented in bus topology, controlled by Telematics Control Units( TCU). The control units communicate with each other and with the connected sensors/actuators via these fieldbuses. The various fieldbus systems such as CAN bus, LIN bus or FlexRay communicate with each other via gateways. The fieldbus clusters in turn consist of several Electronic Control Units( ECU) connected to one or more fieldbuses.
In order to meet the various requirements for safety-related functions, infotainment or real-time behavior, several fieldbus systems are often used. For example, sensor- actuator networks, real-time networks or those for multimedia applications. As with other networks, on-board networks can be subdivided into the physical structure with the corresponding transmission media, the communication structure with its communication protocols, and the application. In an on-board network, the control units functionally correspond to the nodes of a classical network, which fulfills certain functionalities that can be retrieved by slaves.
On-board networks with higher supply voltages
In the mid-1990s, there were various activities in Europe and the U.S. for a 42-V on board network and later for the 48-V onboard network to supply powerful components such as electrical units, engines, electric heaters, air-conditioning compressors and other components, with an output of several kilowatts. Higher supply voltages have cost advantages and support effective power distribution. As a result, cable cross-sections can be reduced and simple connectors can be used. This trend is followed by the high-voltage on-board power supplies used in hybrid electric vehicles(HEVs) and electric vehicles(EVs), which have supply voltages of 400 V. If power of more than 10 kW is required for powertrains, currents of more than 250 A must be provided. Future luxury- class e-vehicles are even expected to operate at voltages of up to 1,000 V. These on-board networks are known as HV on-board networks; their supply voltages depend on the vehicle concept - EV, HEV, BEV, PEV, etc. - and on the vehicle type. - and on the vehicle type.