CAN AN AC (ALTERNATING-CURRENT) ELECTRICAL SYSTEM REPLACE THE PRESENTDC SYSTEM IN THE AUTOMOBILE - AN INVESTIGATIVE FEASIBILITY STUDY - PART I - SYSTEM ARCHITECTURE

In the aerospace industry, the 400-Hz ac system replaced the de system , and the latest trend in aerospace industry involves a combination of mixed ac and de electrical system applications. With more and more eq uipment in the newer automobiles and a corresponding increase in power requirement, it is anticipated that in the not too distant future hig her voltage and/or some different architecture will be necessary in or der to have an efficient electrical system. The question addressed in this paper is whether an alternative single-or three-phase ac electric al distribution and load system could replace the present de system an d, if so, what kind of architecture should be used. In this paper, fir st the electrical system architecture is described. Other issues discu ssed include the comparison of relative cost and size issues arising d ue to: 1) additional dc-ac power electronic converter hardware; 2) cha nges in the wiring system; and 3) the use of induction motors which ca n adequately handle the motor loads without any added power and/or con trol electronics at certain chosen frequency(ies), It is shown that fo r a three-phase system there will be a net total saving. The benefits of the ac system are not just based on cost, but on reliability and ro bustness as well. It seems that a replacement of the present electrica l system with a three-phase ac system could be a reasonable step towar d alternative electrical system selections.