Multidomain modeling has become more and more important, especially since integrated design strategies have imposed themselves for reaching higher standards in system efficiency and precision. This research deals with electromechanical systems with large multibody structure and tight interaction between electrical and mechanical parts. In the first part of this work, the author present an in depth confrontation of existing unified modeling theories: Bond Graphs, Linear Graphs and Virtual Work Principle. A simple example is used to illustrate the use of these theories and their application on multibody systems is discussed. A new modeling strategy is proposed in the second part of this text. On the basis of a symbolic implementation of dedicated formalisms, the author proposes to generate the symbolic submodels for the mechanical and the electrical parts separately and to couple the obtained equations into one global symbolic model, provided to the numerical integrator. This modeling strategy is then applied to several applications. Firstly, simple electrical circuits and electromechanical systems are considered in order to validate the tools which were developed during this work. The validation was achieved by comparison with existing modeling tools and also with experimental measurements. Secondly, more complex industrial applications are presented : 1. a parking gate system, consisting in a flexible barrier mounted on a six-bar mechanism driven by a three phase induction motor, 2. an articulated railway bogie actuated by two induction motors.