Optimization of a 42V/14V dc-dc converter for vehicular electrical network

The aim of this paper is to present an analytical optimization approach of a 42V-14V converter for the automotive domain. Indeed, the amount of electronic equipment on board of vehicles and the electrical power requirement of motorcars has increased steadily during the past 50 years, starting at about 100 W in 1950 reaching 2 kW in 2000, it will reach 5 kW in 2010. The 14V network is not able to supply enough current for the increasing power requirement. So, a 42V network is generalized [J.G. Kassakian, February 2000]. A special dc/dc converter is therefore needed to interconnect these two networks [M. Hasebe], [C. Larouci et al.], [C. Larouci et al.]. In this context, the paper develops an analytical optimization methodology under constraints of a 42V-14V dc-dc converter. It recommends the use of analytical models to optimize the passive element volume by respecting EMC standards, by minimizing the whole dissipated losses, by constraining the semiconductor junction, the winding and the magnetic circuit temperatures and by insuring the controlled converter stability and a good dynamic performances. The developed optimization procedure is validated by numerical simulation and measures.