In this research project, GREAH intends to extend its research work towards increasing the range of electric vehicles by developing and mastering innovative structures of on-board electric energy sources for the supply of the vehicle. Thus, this project fits perfectly with Axis 1 — Electric Powers 3conversation and Transformation" and 2 — Integration and Reliability of the GRR EEM Electronic Network [1]. It also received funding during the GRR EEM 2015 call for projects (EUR 40 000) This project is part of the research work carried out at international level for the development of electric power sources for the supply of electric and/or hybrid vehicles. Indeed, the development of electric vehicles is essentially hampered by their limited autonimity compared to thermal-motor vehicles. This limited range comes from the capacity of the batteries used by most vehicles. Although they use the latest technologies, these batteries are not yet efficient enough to run hundreds of kilometres. To address this, research is carried out in three areas: 1) Improving the energy density of batteries;2) Use of fuel cells;3) Development of energy efficient generators.This last point is based on two technologies that can be considered mature: combustion engines and electric machines. The development of free piston energy converters (CEPL) fits perfectly into the framework. These systems have interesting advantages over conventional generators. Indeed, they allow the obtimisation of combustion through the use of a variable compression rate, and consequently an improvement in the efficiency of combustion, with the possibility of using different types of fuels. In addition, direct conversion reduces the number of moving parts and friction losses, leading to a further improvement in efficiency [2].The free piston energy converter (CEPL) is a multi-physical system [2]-[7].In this type of converter the combustion energy of a fuel is converted into pneumatic [5], hydraulic [6], or electric [7]. This project will focus on the need for multi-disciplinary teams. It requires the mastery of several disciplines: thermodynamic, hydraulic, electromagnetic, power electronics, automatic, etc.We will therefore work on the development of an integrated generator set, with good efficiency, for the feeding of hybrid vehicles series. Several projects for free piston energy converters have been studied in the past [7], [8]. However, given the technological solutions available at the time, these projects only gave rise to prototypes and did not undergo mass production. The idea of this new project is to study this type of system in the light of the technological solutions currently available, taking into account the advances made. This project will lead us to study current scientific issues. The linear electric machine must be capable of operating in engine mode, and generator, so as to improve combustion and increase the efficiency of conversion. In doing so, it is also possible to use different types of fuels. These factors require a particular dimension of the electrical machine, its power supply is its control [9]. Linear tubular machines seem to be best suited for such an application (Figure 2). Their thermal behaviour is a little studied and deserves an in-depth study [9]