TABLE OF CONTENTS In a conventional vehicle architecture, all the electric loads are supplied by a 14 V DC link connected to a 12 V battery and to an engine-driven alternator. The most common electric loads are: ignition system, lighting system, and starter electric motor. Additional electric loads include power steering motors, anti-lock motors, fans and pumps, air conditioning, active suspension actuators, catalyst heaters, throttle actuators, etc. In common passenger cars today the electric power demand is around 1 kW. Luxury cars may have a maximum electrical load of 2 kW. However, current predictions suggest that the electrical load in automobiles will increase in the next years up to 6 10 kW [116].
In this context of "more electric cars" technology, the conventional architecture might be complemented with a higher voltage DC link, typically at 42 V. In this way it will be possible to introduce new electric loads, e.g. the coolant pump that in the conventional architecture is driven by the engine. The payback usually is a higher flexibility in the operation as well as the possibility of gaining higher efficiency and reliability. The advent of a 42 V system would also facilitate the possibility of introducing the integrated starter/alternator (ISA) concept, i.e., a "mild" hybrid configuration for effective stop-and-go operation and some degree of regenerative braking [200].
To manage the presence of electric sources at different voltage levels, various solutions have been proposed. They are roughly classifiable in: (1) multilevel systems, in which a single high-voltage...
