Automotive Power Net Development


Facing the challenges of further efficiency improvement and steadily declining CO2 limits in the automotive sector, the importance of powernet development has grown continuously. In addition to the initially dominant demand for a secure energy supply for the electrical components and a sufficient battery charge, other aspects are becoming more and more relevant. The increasing demand for energy, new comfort and assistance functions, the electrification of auxiliary systems, as well as the automated driving require new impulses in the area of electrical systems and the electrical energy management.

  Generator RWTH Aachen | VKA

In particular, dual battery and dual voltage power supply systems in the low-voltage range promise significantly increasing efficiency without large technological or financial efforts. Depending on the vehicle segment either an extension of the established 12 V micro hybrid technologies or new 48 V mild hybridization concepts are conceivable. Both technologies come with an increased recuperation capability, improved stop-start systems, new functionalities such as sailing or boosting and need comparatively minor adjustments of the drive train. However, they require a lot of further developments in the field of energy management to enable efficient power distribution and high availability of the consumption reducing functions.


HiL Test Bench for Automotive Power Nets

For this purpose, a Hardware-in-the-Loop (HiL) test bench for automotive power nets has been developed at the Center for Mobile Propulsion. By its flexible concept the test bench creates the necessary degrees of freedom for a target-oriented power net development. An adjustable belt drive allows to test a broad range of energy converters from a conventional alternator up to a 48 V belt starter generator. On the electrical side variable dual battery topologies can be simulated. Furthermore, controllable loads can emulate any electrical consumers up to a maximum load current of 1050 A. High-precision measurement technologies provide all relevant mechanical and electrical parameters. The power net test bench is coupled via a dSPACE Scalexio HiL simulator to the virtual test environment. In addition to the test bench control, the vehicle simulation including power management functions is carried out in real time on the simulator. The main interface to the mechanical structure is the speed and load behavior of the drive machines, directly affecting the electrical system by the belt-driven generator.

  HiL - Testbench RWTH Aachen | VKA

The HiL test bench for automotive power nets establishes the necessary conditions for an application-oriented development of energy management functions based on variable load scenarios in realistic driving cycles. Moreover, valid statements on the performance of components, but also on the electrical energy balance and voltage stability of the power supply system are possible by replicating the physical power net. Thus, a significant contribution to the development of advanced automotive power nets can be achieved.



Anforderungen an die robuste Spannungsversorgung in Fahrzeugen mit hybriden Antriebsystemen

Energy balance of 48 V mild hybrid vehicles with electric driven supercharger

Next-Generation Low-Voltage Power Nets - Impacts of Advanced Stop/Start and Sailing Functionalities



Philip Griefnow

Research Associate


+49 241 80 48239