In the automotive industry a strong trend towards
electrification is determined. It offers the possibility of a more
flexible actuation of the vehicle systems and can therefore reduce
the fuel consumption and CO₂ emissions for modern vehicles. This is
not only valid for typical drive train components, e.g., for hybrid
or pure electric vehicles, but also for chassis components and
auxiliaries like power-steering pump or air-conditioning
compressor. However, a further electrification is limited by the
14V power net of conventional passenger cars. The high electric
currents required by new/additional electrical components may lead
to increased line losses and instability in the vehicle electrical
system. With the introduction of a medium voltage level (≺60V)
these problems can be circumvented. Nevertheless, the complexity of
the vehicles with strong electrification and several voltage levels
also raise the effort of design and development due to the
multidisciplinary nature of the electrified vehicle systems.
To meet the challenge of the problem mentioned above, the
presented work proposes a modern co-simulation approach to make the
design and evaluation of a vehicle electrical system more
efficient. The simulation process becomes more modular and the
strength of the domain-specific simulation tools can be optimally
utilized. On the example of a hybrid electric vehicle (HEV)
concept, simulation models from different fields of expertise
(electrics, electronics, mechanics and thermodynamics) are
integrated into an overall vehicle simulation model. The specific
simulation tools are coupled via the co-simulation platform ICOS
(Independent Co-Simulation) developed at the Virtual Vehicle
Competence Center (ViF). Following that, the virtual prototype car
is used to analyze the stability behavior of various two-voltage
vehicle electrical system configurations including an electric
double-layer capacitor (EDLC) as energy buffer or active
stabilization with an additional DC/DC converter.