42V power system architecture development

With the increaslig demand for more fuel efficiency and environmentally friendly car coupled with the consumers´ drive for more comfort, safety and luxury car has led to the introduction of more electrical and electronic systems to the passenger car. This is further impacted by the current trend in automotive industry to replace mechanical and hydraulic system with their electrical counterparts. The handling capability of the current 14V DC system is getting very close to reaching the limits. To meet the new growing electrical power demands with minimum fuel consumption and minimum environmental effects, the automobile industry is looking into increasing the present voltage threefold, from 14V to 42V for future cars. A shift towards a 42V system will cut the current of the vehicle by a factor of three. With the lower current, the size and cost of power semiconductors can be reduced, allowing for their use in applications that could not use semiconductors before. In this paper, a detailed mathematical model for a 3-phase, 4kW and 42V Lundell alternator average electrical equivalent circuit will be presented along with the DC/DC converter based architectures for dual-voltage systems. The performance of the 42V Lundell alternator with the interleaved six-phase buck dc-to-dc converter system is modelled using Simulink software to assess the effectiveness of the model and its transient behaviour.