With increasingly restrictive emission and energy consumption regulations and a social awareness of the need to protect the environment, EVs are attracting increasing attention from the automotive sector, politicians and consumers. PMSMs, due to their high-power density and efficiency, have been the dominant traction technology since the 1990s. However, these engines are manufactured from rare earth, non-ecological materials and are subject to much controversy. Of all the rare-earth-free machine alternatives, switched reluctance machines (SRMs) are considered the most promising candidates for the next generation of EVs. However, because of the exchange of large amounts of magnetic energy between the windings and the power source, large capacitors need to be incorporated into the DC bus. Based on the analysis carried out, this thesis presents and validates a novel modulation algorithm to solve the problem of high currents in the DC bus of the SRM converter. This approach has been called Synchronized Switching Modulation, which uses a phenomenon of energy exchange between phases to reduce the dependence on the DC bus. This reduction in current results in less thermal stress, which increases the service life of the capacitors. This second aspect is also analysed in the present thesis by carrying out a study on models of service life, accumulated damage and reliability of the capacitors that make up the SRM converter. Finally, in the present thesis a methodology is defined to predict the life of a DC bus capacitor of an SRM converter from the current that passes through it, that is, from the set of operational points (or driving cycle) in which the EV traction train is working.