Abstract
In these papers are presented the structure and particularities of two types of d.c. converters witch can be used in the electric system of automotives with engine, electric vehicles or hybrid vehicles.
The equivalent circuits of buck and boost converters deduced from the energetical reasons and the analyze of the power transfer through those converters are presented. To the analyze of the power transfer are done considering two functioning regimes of the D.C. electrical converters: constant frequency and variable duty factor respectively constant duty factor and variable frequency.
In the final part of the papers are presented the conclusions resulted from the analyze of the practical obtained results.